文章
Dummer. ゛☀
2017年09月18日
Injury due to salt is most common on landscape plants growing adjacent to highways, streets, sidewalks, and driveways that are regularly salted during the winter for ice control. Most of the salt used for deicing purposes is sodium chloride, ordinary rock salt or table salt. On highways, the major problem to plants is caused by salt spray kicked up by fast moving traffic on wet, salted roads. The salt spray is deposited on adjacent plants causing dehydration of evergreen leaves. In the city, the major problem is salt runoff washing into the soil. Salt in the soil may be absorbed by the roots and cause direct toxic effects.
Symptoms and Diagnosis
Salt spray causes bud death and twig dieback. Subsequent shoot growth at the branch base produces clusters of twigs known as "witches' brooms." Symptoms typically become evident in the spring. In evergreens and conifers, salt spray causes leaf browning or yellowing, needle tip flecking, and twig dieback. Salt in the soil is slower acting and may not affect plants for several years. Symptoms include an initial blue green cast to the foliage, marginal leaf burn or needle tip burn, reduction in leaf, flower and fruit size, premature fall coloration and defoliation, stunting, and a general lack of vigor. The symptoms often become evident in late summer or during periods of hot dry weather.
Integrated Pest Management Strategies
1. Reduce salt use. The most important method of preventing salt injury to plants is reducing the amount of salt used for deicing. Pure salt should never be applied. Salt should always be mixed with an abrasive such as sand, cinders, or ash. This combines the melting power of the salt with the grittiness of the abrasive so less total salt is needed. Commercial deicing products containing calcium chloride may be used instead of rock salt. These products will not damage the soil but will still injure plants, so they too should be mixed with abrasives and applied with the same precautions.
2. Apply salt carefully. Application should be limited to high risk locations such as high speed roads, intersections, hills, steps, and walkways. Avoid spilling or applying in heaps.
3. Leach salted soils. If salt has already entered the soil, water these areas heavily in the spring to help leach the salt out of the soil. This method, however, is only effective on well-drained soils. It is not effective on fine textured, compacted soils where water does not drain readily.
4. Protect plants. Plants may be protected from salt spray by placing materials such as plastic, burlap, plywood, or window screen on or in front of them. This provides a physical barrier that prevents salt spray from contacting the plant.
5. Avoid planting in drainageways or in areas where runoff collects. Salt spray damage can be avoided by planting trees and shrubs away from the spray drift zone, at least 50 feet from a highway or further if downwind. Plants vary in their sensitivity to salt. It should be emphasized that even tolerant plants are not immune to injury.
Symptoms and Diagnosis
Salt spray causes bud death and twig dieback. Subsequent shoot growth at the branch base produces clusters of twigs known as "witches' brooms." Symptoms typically become evident in the spring. In evergreens and conifers, salt spray causes leaf browning or yellowing, needle tip flecking, and twig dieback. Salt in the soil is slower acting and may not affect plants for several years. Symptoms include an initial blue green cast to the foliage, marginal leaf burn or needle tip burn, reduction in leaf, flower and fruit size, premature fall coloration and defoliation, stunting, and a general lack of vigor. The symptoms often become evident in late summer or during periods of hot dry weather.
Integrated Pest Management Strategies
1. Reduce salt use. The most important method of preventing salt injury to plants is reducing the amount of salt used for deicing. Pure salt should never be applied. Salt should always be mixed with an abrasive such as sand, cinders, or ash. This combines the melting power of the salt with the grittiness of the abrasive so less total salt is needed. Commercial deicing products containing calcium chloride may be used instead of rock salt. These products will not damage the soil but will still injure plants, so they too should be mixed with abrasives and applied with the same precautions.
2. Apply salt carefully. Application should be limited to high risk locations such as high speed roads, intersections, hills, steps, and walkways. Avoid spilling or applying in heaps.
3. Leach salted soils. If salt has already entered the soil, water these areas heavily in the spring to help leach the salt out of the soil. This method, however, is only effective on well-drained soils. It is not effective on fine textured, compacted soils where water does not drain readily.
4. Protect plants. Plants may be protected from salt spray by placing materials such as plastic, burlap, plywood, or window screen on or in front of them. This provides a physical barrier that prevents salt spray from contacting the plant.
5. Avoid planting in drainageways or in areas where runoff collects. Salt spray damage can be avoided by planting trees and shrubs away from the spray drift zone, at least 50 feet from a highway or further if downwind. Plants vary in their sensitivity to salt. It should be emphasized that even tolerant plants are not immune to injury.
0
0
文章
Dummer. ゛☀
2017年09月18日
Pestalotiopsis is a type of needle blight fungal disease that is primarily found on arborvitae (Thuja). It is usually considered a secondary disease that attacks foliage that has been injured or weakened by unfavorable weather or growing conditions. The disease may kill the smaller twigs where the infected needles died.
Symptoms and Diagnosis
The blight usually starts at the tip of the foliage and progresses towards the leaf base. Affected foliage color progresses from green to yellowish, then to a dark brown that looks almost black. Twig tips can also turn brown and have black, pimple-like, pinhead size, fungal fruiting structures dotting the surface. Usually, killed foliage is near the base of the plant where foliage is relatively dense. The plants may appear scorched.
Life Cycle
Infections can occur at anytime of year. However, spring is the most likely time because favorable weather conditions exist and plants are showing stress from winter conditions.
Integrated Pest Management Strategies
1. Avoid over crowding plants to allow for sufficient sunlight and air circulation.
2. Keep plants healthy with good cultural practices. Follow proper watering, fertilization practices and minimize any mechanical and snow/ice damage, etc. that could cause an entry point for the fungus.
3. Prune out dead foliage and twigs as soon as possible.
4. Application of fungicides should not be necessary. If necessary in certain circumstances (e.g. a nursery), copper fungicides are registered for this use as a preventative. Always read and follow product label directions before application to plants.
Symptoms and Diagnosis
The blight usually starts at the tip of the foliage and progresses towards the leaf base. Affected foliage color progresses from green to yellowish, then to a dark brown that looks almost black. Twig tips can also turn brown and have black, pimple-like, pinhead size, fungal fruiting structures dotting the surface. Usually, killed foliage is near the base of the plant where foliage is relatively dense. The plants may appear scorched.
Life Cycle
Infections can occur at anytime of year. However, spring is the most likely time because favorable weather conditions exist and plants are showing stress from winter conditions.
Integrated Pest Management Strategies
1. Avoid over crowding plants to allow for sufficient sunlight and air circulation.
2. Keep plants healthy with good cultural practices. Follow proper watering, fertilization practices and minimize any mechanical and snow/ice damage, etc. that could cause an entry point for the fungus.
3. Prune out dead foliage and twigs as soon as possible.
4. Application of fungicides should not be necessary. If necessary in certain circumstances (e.g. a nursery), copper fungicides are registered for this use as a preventative. Always read and follow product label directions before application to plants.
0
0
成长记
cclecombe
2017年09月17日
Picked up some rooting powder today so ive applied it to the root growing on my monstera clipping.
0
0
文章
Dummer. ゛☀
2017年09月17日
Don’t assume that you’re limited to growing succulents in traditional flower pots. Because they’re so flexible, they can be grown in just about any container. We’ve even seen succulents planted in a shoe. Below are some options for unique potted succulent ideas.
Hollow out some logs or stumps and fill them with soil. Plant the succulents inside for an inexpensive, natural look. An old birdbath or fountain makes a wonderful home for these plants. So do old watering cans. Because succulents don’t require ample amounts of water, you can plant them into furniture. Remove the center slat of a farmhouse table and replace it with a succulent garden. Grow succulents along the center of your coffee table. Smaller containers make your succulent garden portable. Use it as the centerpiece one night at dinner, then move it to your foyer to greet you with freshness when you enter the house.
Hollow out some logs or stumps and fill them with soil. Plant the succulents inside for an inexpensive, natural look. An old birdbath or fountain makes a wonderful home for these plants. So do old watering cans. Because succulents don’t require ample amounts of water, you can plant them into furniture. Remove the center slat of a farmhouse table and replace it with a succulent garden. Grow succulents along the center of your coffee table. Smaller containers make your succulent garden portable. Use it as the centerpiece one night at dinner, then move it to your foyer to greet you with freshness when you enter the house.
1
2
文章
Dummer. ゛☀
2017年09月17日
Mushrooms growing in lawns are common occurrences especially during rainy weather. They live off decaying organic matter in the soil, often decaying tree roots, and are not harmful to the lawn. They will naturally disappear as they age or they may be collected and composted, knocked down with a rake or hoe, or mowed over with your lawnmower. Mushrooms should never be collected and eaten unless you are expert in their identification. To the novice gardener, many poisonous mushrooms can look very similar to edible ones. Don’t take a chance.
Mushrooms that develop in a ring in the lawn are called fairy rings. They will be the focus of the remainder of this sheet.
Fairy rings are caused by many different soilinhabiting fungi of the class Basidiomycetes. These fungi can cause the development of rings or arcs of deep green grass as well as unthrifty or dead grass.
Fairy ring fungi do not attack grass directly, but break down organic matter in the soil. As a result, nitrogen is released which the grass uses, causing it to grow and develop a contrasting green ring. In cases where the mycelia of the fungus get very dense and inhibit water movement into the soil, grass in the arc may turn brown. Mycelia may also deplete soil nutrients and produce toxic levels of hydrogen cyanide. The mushrooms that appear after rainfall are the fruiting bodies of the fungus.
The organic matter fairy rings break down is often old tree stumps, roots, logs, lumber, and other larger pieces of organic material in the soil below the lawn. Once this material is depleted, the fairy ring will disappear. This may take considerable time. Several fairy rings may appear relatively close together, especially on lawns that exist on sites that were previously wooded areas. When this occurs, it becomes noticeable that fairy rings do not cross each other, as fungal activity ceases when fungi from different rings contact each other.
Symptoms and Diagnosis
Dark green circles, arcs, or rings of thick, fastgrowing grass develop anytime from green-up in the spring (most common) until the first hard frost in the fall. These rings are most commonly between 2 and 15 feet in diameter, although they may be larger or smaller. Mushrooms or puffballs may appear under wet conditions in the same ring pattern. In some cases, a ring of brown or dead grass may appear.
Life Cycle
Approximately 50 species of fungi are known to form fairy rings in turf, with Marasmius oreades, Agaricus campestris, Lycoperdon spp., and Scleroderma spp. being the most common. These fungi decompose organic debris in the soil and thatch.
Fairy ring starts from a piece of mycelium or spore at a single point feeding in the thatch layer or on soil organic matter. The uniform outward growth of the fungus results in the development of rings.
Under certain conditions, and with certain fairy ring fungi, a ring of dead grass develops. Some of the responsible fungi have been shown to penetrate and kill root cells resulting in dead rings of grass. In addition, the mycelia of some fairy ring fungi are reported to be hydrophobic, creating a waterimpervious layer resulting in drought-stress problems for the grass. Once the soil under this mycelial layer becomes dry, it is very difficult to wet, and the roots of the grass plant die.
Integrated Pest Management Strategies
1. Fertilizer. Use of a nitrogen fertilizer can mask the symptoms of fairy ring by causing the rest of the lawn to green up. Using a soil needle (deep root feeder) to aerate and irrigate dead and dying rings is recommended.
2. Removal. Fairy ring development can be traced to buried organic debris. Undecomposed tree roots, wood scraps from construction projects, and other organic debris are commonly colonized by the fairy ring fungi and should be removed before establishing a new lawn. Use clean, ring-free sod for a new or renovated lawn.
Destroying existing turf may be required in persistent cases. Discard or kill a strip of sod 1 to 2 feet wide on each side of the zone of lush turf with a non-selective herbicide. Cultivate the area repeatedly to thoroughly mix the ring and nonring soil. Eliminate dry spots by soaking the cultivated area with water. Reseed or install clean, ring-free sod.
3. Thatch. Eliminate thatch buildup with a dethatching program.
4. Fungicides. Some fungicides are available for suppression of fairy ring, however, they may be only temporary as the decaying material may still be present.
Organic Strategies
Strategies 2 and 3 are strictly organic approaches. Using an appropriate organic fertilizer would be a viable organic approach to Strategy 1.
Mushrooms that develop in a ring in the lawn are called fairy rings. They will be the focus of the remainder of this sheet.
Fairy rings are caused by many different soilinhabiting fungi of the class Basidiomycetes. These fungi can cause the development of rings or arcs of deep green grass as well as unthrifty or dead grass.
Fairy ring fungi do not attack grass directly, but break down organic matter in the soil. As a result, nitrogen is released which the grass uses, causing it to grow and develop a contrasting green ring. In cases where the mycelia of the fungus get very dense and inhibit water movement into the soil, grass in the arc may turn brown. Mycelia may also deplete soil nutrients and produce toxic levels of hydrogen cyanide. The mushrooms that appear after rainfall are the fruiting bodies of the fungus.
The organic matter fairy rings break down is often old tree stumps, roots, logs, lumber, and other larger pieces of organic material in the soil below the lawn. Once this material is depleted, the fairy ring will disappear. This may take considerable time. Several fairy rings may appear relatively close together, especially on lawns that exist on sites that were previously wooded areas. When this occurs, it becomes noticeable that fairy rings do not cross each other, as fungal activity ceases when fungi from different rings contact each other.
Symptoms and Diagnosis
Dark green circles, arcs, or rings of thick, fastgrowing grass develop anytime from green-up in the spring (most common) until the first hard frost in the fall. These rings are most commonly between 2 and 15 feet in diameter, although they may be larger or smaller. Mushrooms or puffballs may appear under wet conditions in the same ring pattern. In some cases, a ring of brown or dead grass may appear.
Life Cycle
Approximately 50 species of fungi are known to form fairy rings in turf, with Marasmius oreades, Agaricus campestris, Lycoperdon spp., and Scleroderma spp. being the most common. These fungi decompose organic debris in the soil and thatch.
Fairy ring starts from a piece of mycelium or spore at a single point feeding in the thatch layer or on soil organic matter. The uniform outward growth of the fungus results in the development of rings.
Under certain conditions, and with certain fairy ring fungi, a ring of dead grass develops. Some of the responsible fungi have been shown to penetrate and kill root cells resulting in dead rings of grass. In addition, the mycelia of some fairy ring fungi are reported to be hydrophobic, creating a waterimpervious layer resulting in drought-stress problems for the grass. Once the soil under this mycelial layer becomes dry, it is very difficult to wet, and the roots of the grass plant die.
Integrated Pest Management Strategies
1. Fertilizer. Use of a nitrogen fertilizer can mask the symptoms of fairy ring by causing the rest of the lawn to green up. Using a soil needle (deep root feeder) to aerate and irrigate dead and dying rings is recommended.
2. Removal. Fairy ring development can be traced to buried organic debris. Undecomposed tree roots, wood scraps from construction projects, and other organic debris are commonly colonized by the fairy ring fungi and should be removed before establishing a new lawn. Use clean, ring-free sod for a new or renovated lawn.
Destroying existing turf may be required in persistent cases. Discard or kill a strip of sod 1 to 2 feet wide on each side of the zone of lush turf with a non-selective herbicide. Cultivate the area repeatedly to thoroughly mix the ring and nonring soil. Eliminate dry spots by soaking the cultivated area with water. Reseed or install clean, ring-free sod.
3. Thatch. Eliminate thatch buildup with a dethatching program.
4. Fungicides. Some fungicides are available for suppression of fairy ring, however, they may be only temporary as the decaying material may still be present.
Organic Strategies
Strategies 2 and 3 are strictly organic approaches. Using an appropriate organic fertilizer would be a viable organic approach to Strategy 1.
0
0
文章
Dummer. ゛☀
2017年09月17日
Annual winter weeds germinate in the fall and winter and grow actively in spring. Gardeners are often surprised how quickly these weeds can seemingly pop up overnight in their yards and gardens, being unaware that they may have been growing slowly all winter long. After they flower in spring they die and disappear for the summer only to return in fall or winter when new seeds germinate.
Some of the more common annual winter weeds in the Midwest are henbit, deadnettle, common chickweed, annual bluegrass, wild mustards, prickly lettuce, Persian speedwell, horseweed, cheatgrass and rabbitfoot clover. Some people do not consider these plants as weeds, as some can also be used for food or have been used for medicinal purposes.
Deadnettle and Henbit
Deadnettle (Lamium purpureum) and henbit (Lamium amplexicaule) are often confused. These winter weeds are both in the mint family and have square stems with opposite leaves. Both plants have pink/purple flowers and can reach 16 inches high but more commonly reach only about 6 inches high in the Midwest. Henbit has circular or rounded leaves with rounded teeth on the leaf margin. Deadnettle has triangular shaped leaves and less deeply lobed than henbit and at times the upper leaves are purple or red. Both plants are decumbent in youth but more upright with age. Flowers appear in whorls in the leaf axis of upper leaves from March to May and are tube-like with 2 lips.
Common Chickweed
Common chickweed (Stellaria media) is a winter annual with a shallow fibrous root which grows in moist, cool shaded areas. The bright green leaves are about ½ inch long, smooth, pointed at the tip, and elliptic in shape. They have opposite branching, slender, creeping stems which root at the nodes. The white flowers of chickweed are ½ inch in diameter and star-shaped with five deeply notched petals. Flowering occurs from early spring to fall. Chickweed reproduces by seed and rooting at the nodes on prostrate stems. The fruit contains many seeds within a dry capsule which splits when mature, shaking out the seeds onto the soil. Seeds will germinate at any time of the year but particularly in spring and autumn. Seeds are dispersed in mud on footwear and tires as well as by animals. Chickweed is found in turfgrass as well as nursery, cultivated horticultural, and agricultural crops. It is a host of several damaging virus diseases of crop plants which can be carried in the chickweed seeds.
Annual Bluegrass
Annual bluegrass (Poa annua) is one of the most common weeds in the United States. It is a native of Europe. Golf courses consider it a particular problem. It is identified by its boat-shaped leaf tips which curve up like the bow of a boat. Annual bluegrass is upright growing (growing 3-12" high) and can be noticed by its pale green spring appearance. It can produce 100 seeds in 8 weeks. It germinates when the temperature falls below 70 degrees and throughout the winter. It usually dies in the summer.
Prickly Lettuce
Prickly lettuce (Lactuca serriola) is in the aster family. It can grow up to 5’ tall. Sometimes this winter weed can be a biennial. It has creamy yellow aster-like flowers. Butterfly larvae feed on this plant. Alternate leaves branch off the main stem. There is a prominent midvein on each leaf which contains a row of spines on the bottom surface. Several edible lettuces, such as crisphead, butterhead, cos, Romaine, loose leaf or bunching, and stem lettuce or celtuce were all derived from this species.
Persian speedwell
Persian speedwell (Veronica persica) is a winter annual with slender, weak stems that grow along the ground but turn up at the tips. In shaded areas it tends to grow more upright. The stems are covered with finely pointed, flattened hairs. The hairy leaf blades are oval to roundish with rounded teeth around the edges. The lower leaves are arranged oppositely and occur on petioles, but the upper leaves occur on the more erect flowering stems, are arranged alternately, and do not have petioles. The flowers occur singly on long, slender flower stalks which arise from the leaf axils. The small flowers are usually light blue in color with darker blue lines and a pale blue to white center. Prior to flowering, the speedwells are often misidentified as ground ivy, henbit, or purple deadnettle. However, ground ivy does not have hairy leaves and both henbit and purple deadnettle have leaves that are arranged oppositely along the flowering stem. Speedwell is primarily a weed of lawns, turfgrass, landscapes, nurseries, and winter small grains.
Horseweed
Horseweed or mare's tail (Conya canadensis) can grow to 6 1/2 ’ tall. A mature plant has alternate leaves that have no petiole. Young leaves are egg-shaped with toothed margins but mature leaves are 3-4 inches long, hairy, and oblanceolate in shape (broader and rounded at the apex, and tapering at the base.) Plant has a taproot. Small inconspicuous flower heads are at the top of the central stem. Flowers are about 1/4 inch in diameter, with white or slightly pink ray flowers. This is a composite flower and there are many tiny disk flowers in the flower head (like daisies and coneflowers). In the early stages, this plant resembles shepherd’s purse or Virginia pepperweed. The fruit (or seed) is a 1/16 inch long achene that does not split open when it is ripe. It tapers from the apex with many small bristles that aid in wind dispersal. This plant is susceptible to aster yellows.
Cheatgrass
Cheatgrass (Bromus tectorum) is a winter annual that has a fine feathery appearance, with slender light-green stems drooping at the tips where the seeds form. Seed spikelets and their bristles can be 2 inches long. Mature grass grows to 30 inches and turns first purple, and then brown, as it dries. Cheatgrass occurs throughout most of the United States and is on state noxious weed lists in 43 states. It grows on rangelands, pastures, prairies, fields, eroded sites and roadsides. Cheatgrass can alter ecosystems by maintaining dominance for years on sites where native vegetation has been eliminated or severely reduced due to grazing, cultivation, or fire. Moreover, it increases the frequency and timing of wildfires. At maturity the sharp-pointed bristly sections can injure wildlife species by working into the nose, ears, mouth, or eyes. Spikelets can also cling to clothing.
Rabbitfoot Clover
Rabbitfoot clover (Trifolium arvense) is in the pea family. This winter weed has a multi-branched growth habit and is 4-16 inches tall. It came from Eurasia and is naturalized now. Both stems and leaves are densely hairy. Leaves consist of 3 narrow leaflets with minute teeth-like projections at the tip. Flowers are small and pink to purple in color. They are clustered in grayish soft and silky cylinder-shaped heads. It flowers in the spring, and reproduces by seed. Rabbitfoot clover is found in the Southeast United States, west to Louisiana and north to Missouri. Rabbitfoot clover contributes nitrogen to the soil, as do other clovers, but it grows in unimproved sandy soils in semi-arid grasslands.
Bedstraw
Bedstraw (Galium aparine) is a winter annual with square stems and short, downward pointing hooks on the stem corners. The stems are weakly branched, prostrate on the ground or climbing on other plants producing a tangled mass. The rough hairy leaves grow in whorls of six to eight. The tiny white flowers have four-lobed pointed petals on long flower stalks. Bedstraw is found in moist shady areas, thickets, valleys, roadsides, waste ground, under trees, and clearings. The hooked spines of the stems, leaves and seeds cling to just about everything and are difficult to remove. The burr-like seeds are produced in pairs and are covered with hooked hairs. This clinging characteristic minimized matting when bedstraw was used as a mattress filling.
Shepherd's Purse and other mustards
Shepherd’s purse (Capsella bursa-pastoris) is a winter annual with erect stems that grow 3 to 18 inches tall from a basal rosette quite similar to that of a dandelion. The rosette grows to be 4 to 8 inches in diameter. Shepherd’s purse has alternate leaves with the lower leaves more deeply lobed than the upper leaves. The flowers are small and white, appearing in clusters at the top of the stalk from early spring to early winter. Each flower has four petals and develops into a heart-shaped or triangular seedpod which, when the pod dries, splits in half releasing the mature seeds. The seedpods are supposed to resemble the purses of ancient shepherds. It does best in sunny, rich, disturbed soil, but it will also grow in partly shaded, extremely poor soils.. It can be found in flowerbeds, lawns, sidewalk cracks and along the edges of sidewalks and paths.
Integrated Pest Mangement Strategies
1. Encourage grass. Keep lawn areas thick and mulch flowerbeds to help prevent weed seeds from germinating.
2. Removal. Dig or pull the weeds in the winter or spring before they flower and set seed for the next year.
3. Good sanitation. Use good cultural and sanitation practices to prevent the spread of weeds. Small weed seeds can be spread by machines, clothing, pets, and by contaminated seed.
4. Use chemical herbicides. For established weeds the best time to apply herbicides is early spring when the weeds are actively growing but before they go to seed. Herbicides containing Dicamba and/or MCPA or MCPP are more effective than 2,4-D alone. After you have identified the weed you have, check product labels or resource materials to see which herbicides are most effective for that weed or combination of weeds. Use herbicides with caution around desirable plants that may be damaged. Read label directions and cautions carefully.
5. Use pre-emergent herbicide. To prevent germination of the seeds of these winter annuals, apply a pre-emergent herbicide, such as, Gallery in late summer or early fall before the weed seeds have germinated.
Some of the more common annual winter weeds in the Midwest are henbit, deadnettle, common chickweed, annual bluegrass, wild mustards, prickly lettuce, Persian speedwell, horseweed, cheatgrass and rabbitfoot clover. Some people do not consider these plants as weeds, as some can also be used for food or have been used for medicinal purposes.
Deadnettle and Henbit
Deadnettle (Lamium purpureum) and henbit (Lamium amplexicaule) are often confused. These winter weeds are both in the mint family and have square stems with opposite leaves. Both plants have pink/purple flowers and can reach 16 inches high but more commonly reach only about 6 inches high in the Midwest. Henbit has circular or rounded leaves with rounded teeth on the leaf margin. Deadnettle has triangular shaped leaves and less deeply lobed than henbit and at times the upper leaves are purple or red. Both plants are decumbent in youth but more upright with age. Flowers appear in whorls in the leaf axis of upper leaves from March to May and are tube-like with 2 lips.
Common Chickweed
Common chickweed (Stellaria media) is a winter annual with a shallow fibrous root which grows in moist, cool shaded areas. The bright green leaves are about ½ inch long, smooth, pointed at the tip, and elliptic in shape. They have opposite branching, slender, creeping stems which root at the nodes. The white flowers of chickweed are ½ inch in diameter and star-shaped with five deeply notched petals. Flowering occurs from early spring to fall. Chickweed reproduces by seed and rooting at the nodes on prostrate stems. The fruit contains many seeds within a dry capsule which splits when mature, shaking out the seeds onto the soil. Seeds will germinate at any time of the year but particularly in spring and autumn. Seeds are dispersed in mud on footwear and tires as well as by animals. Chickweed is found in turfgrass as well as nursery, cultivated horticultural, and agricultural crops. It is a host of several damaging virus diseases of crop plants which can be carried in the chickweed seeds.
Annual Bluegrass
Annual bluegrass (Poa annua) is one of the most common weeds in the United States. It is a native of Europe. Golf courses consider it a particular problem. It is identified by its boat-shaped leaf tips which curve up like the bow of a boat. Annual bluegrass is upright growing (growing 3-12" high) and can be noticed by its pale green spring appearance. It can produce 100 seeds in 8 weeks. It germinates when the temperature falls below 70 degrees and throughout the winter. It usually dies in the summer.
Prickly Lettuce
Prickly lettuce (Lactuca serriola) is in the aster family. It can grow up to 5’ tall. Sometimes this winter weed can be a biennial. It has creamy yellow aster-like flowers. Butterfly larvae feed on this plant. Alternate leaves branch off the main stem. There is a prominent midvein on each leaf which contains a row of spines on the bottom surface. Several edible lettuces, such as crisphead, butterhead, cos, Romaine, loose leaf or bunching, and stem lettuce or celtuce were all derived from this species.
Persian speedwell
Persian speedwell (Veronica persica) is a winter annual with slender, weak stems that grow along the ground but turn up at the tips. In shaded areas it tends to grow more upright. The stems are covered with finely pointed, flattened hairs. The hairy leaf blades are oval to roundish with rounded teeth around the edges. The lower leaves are arranged oppositely and occur on petioles, but the upper leaves occur on the more erect flowering stems, are arranged alternately, and do not have petioles. The flowers occur singly on long, slender flower stalks which arise from the leaf axils. The small flowers are usually light blue in color with darker blue lines and a pale blue to white center. Prior to flowering, the speedwells are often misidentified as ground ivy, henbit, or purple deadnettle. However, ground ivy does not have hairy leaves and both henbit and purple deadnettle have leaves that are arranged oppositely along the flowering stem. Speedwell is primarily a weed of lawns, turfgrass, landscapes, nurseries, and winter small grains.
Horseweed
Horseweed or mare's tail (Conya canadensis) can grow to 6 1/2 ’ tall. A mature plant has alternate leaves that have no petiole. Young leaves are egg-shaped with toothed margins but mature leaves are 3-4 inches long, hairy, and oblanceolate in shape (broader and rounded at the apex, and tapering at the base.) Plant has a taproot. Small inconspicuous flower heads are at the top of the central stem. Flowers are about 1/4 inch in diameter, with white or slightly pink ray flowers. This is a composite flower and there are many tiny disk flowers in the flower head (like daisies and coneflowers). In the early stages, this plant resembles shepherd’s purse or Virginia pepperweed. The fruit (or seed) is a 1/16 inch long achene that does not split open when it is ripe. It tapers from the apex with many small bristles that aid in wind dispersal. This plant is susceptible to aster yellows.
Cheatgrass
Cheatgrass (Bromus tectorum) is a winter annual that has a fine feathery appearance, with slender light-green stems drooping at the tips where the seeds form. Seed spikelets and their bristles can be 2 inches long. Mature grass grows to 30 inches and turns first purple, and then brown, as it dries. Cheatgrass occurs throughout most of the United States and is on state noxious weed lists in 43 states. It grows on rangelands, pastures, prairies, fields, eroded sites and roadsides. Cheatgrass can alter ecosystems by maintaining dominance for years on sites where native vegetation has been eliminated or severely reduced due to grazing, cultivation, or fire. Moreover, it increases the frequency and timing of wildfires. At maturity the sharp-pointed bristly sections can injure wildlife species by working into the nose, ears, mouth, or eyes. Spikelets can also cling to clothing.
Rabbitfoot Clover
Rabbitfoot clover (Trifolium arvense) is in the pea family. This winter weed has a multi-branched growth habit and is 4-16 inches tall. It came from Eurasia and is naturalized now. Both stems and leaves are densely hairy. Leaves consist of 3 narrow leaflets with minute teeth-like projections at the tip. Flowers are small and pink to purple in color. They are clustered in grayish soft and silky cylinder-shaped heads. It flowers in the spring, and reproduces by seed. Rabbitfoot clover is found in the Southeast United States, west to Louisiana and north to Missouri. Rabbitfoot clover contributes nitrogen to the soil, as do other clovers, but it grows in unimproved sandy soils in semi-arid grasslands.
Bedstraw
Bedstraw (Galium aparine) is a winter annual with square stems and short, downward pointing hooks on the stem corners. The stems are weakly branched, prostrate on the ground or climbing on other plants producing a tangled mass. The rough hairy leaves grow in whorls of six to eight. The tiny white flowers have four-lobed pointed petals on long flower stalks. Bedstraw is found in moist shady areas, thickets, valleys, roadsides, waste ground, under trees, and clearings. The hooked spines of the stems, leaves and seeds cling to just about everything and are difficult to remove. The burr-like seeds are produced in pairs and are covered with hooked hairs. This clinging characteristic minimized matting when bedstraw was used as a mattress filling.
Shepherd's Purse and other mustards
Shepherd’s purse (Capsella bursa-pastoris) is a winter annual with erect stems that grow 3 to 18 inches tall from a basal rosette quite similar to that of a dandelion. The rosette grows to be 4 to 8 inches in diameter. Shepherd’s purse has alternate leaves with the lower leaves more deeply lobed than the upper leaves. The flowers are small and white, appearing in clusters at the top of the stalk from early spring to early winter. Each flower has four petals and develops into a heart-shaped or triangular seedpod which, when the pod dries, splits in half releasing the mature seeds. The seedpods are supposed to resemble the purses of ancient shepherds. It does best in sunny, rich, disturbed soil, but it will also grow in partly shaded, extremely poor soils.. It can be found in flowerbeds, lawns, sidewalk cracks and along the edges of sidewalks and paths.
Integrated Pest Mangement Strategies
1. Encourage grass. Keep lawn areas thick and mulch flowerbeds to help prevent weed seeds from germinating.
2. Removal. Dig or pull the weeds in the winter or spring before they flower and set seed for the next year.
3. Good sanitation. Use good cultural and sanitation practices to prevent the spread of weeds. Small weed seeds can be spread by machines, clothing, pets, and by contaminated seed.
4. Use chemical herbicides. For established weeds the best time to apply herbicides is early spring when the weeds are actively growing but before they go to seed. Herbicides containing Dicamba and/or MCPA or MCPP are more effective than 2,4-D alone. After you have identified the weed you have, check product labels or resource materials to see which herbicides are most effective for that weed or combination of weeds. Use herbicides with caution around desirable plants that may be damaged. Read label directions and cautions carefully.
5. Use pre-emergent herbicide. To prevent germination of the seeds of these winter annuals, apply a pre-emergent herbicide, such as, Gallery in late summer or early fall before the weed seeds have germinated.
0
0
文章
Dummer. ゛☀
2017年09月17日
A weed is a plant that is not valued where it is growing and is usually of vigorous growth, especially one that tends to overgrow or choke out more desirable plants. Summer annual weeds emerge in the spring or early summer, grow during the summer, produce seed in mid to late summer, and are killed by frost in the fall. Following are some of the more common summer annual weeds for the St. Louis area. General control measures are listed at the end of this article.
GRASSES
Barnyardgrass
Barnyardgrass (Echinochloa crus-galli) is a summer annual grass that germinates from seeds from late winter or early spring throughout the summer. The stems are usually erect, thick, without hairs, often branched at the lower nodes, and may be tinted red to maroon at the base. The stems may reach 5 feet in height. The smooth, hairless leaves are rolled in the bud and contain neither ligules nor auricles. The dark green leaves, which range from 4 to 20 inches in length, have a distinct white midvein range. The seed head is green to reddish purple, with conspicuous, short stiff bristles or barbed spikelets. The roots are fibrous. Under close mowing, the broad, compressed purple sheaths of barnyardgrass lie flat on the ground and spread in a semicircular pattern. Barnyardgrass is found in moist soils, especially soils high in nutrients.
Crabgrass
Crabgrass, large and smooth (Digitaria sanguinalis, Digitaria ischaemum) are pale green summer annuals that has a prostrate or ascending growth habit. The two main species of crabgrass that occur in Missouri are smooth and large. Smooth crabgrass may be distinguished from large crabgrass by the absence of hairs on the leaves and sheath. Also smooth crabgrass does not root at the nodes like large crabgrass. Both species have a long, jagged membranous ligule and have no auricles. Crabgrass forms dense, unsightly patches that smother desirable turf grasses. Germination occurs when soil temperatures consistently reach 55 degrees F and is generally killed at the first frost. A crabgrass plant which needs warm soils and sunlight can produce 150,000 seeds. The seed head is composed of 2-6 branches (spikes) at the top of the stems forming 2 rows along the spike.
To control early in the season, use a pre-emergent herbicide as soon as soil temperatures reach 55 degrees F for a period of four days about the time forsythia blooms. A pre-emergent herbicide is recommended even if some crabgrass plants have germinated. There will still be crabgrass seed in the soil and the herbicide can prevent further infestation. Do not aerate after a pre-emergent herbicide application. For crabgrass control after germination, use a post-emergent selective grass herbicide.
Fall Panicum
Fall panicum (Panicum dichotomiflorum) is known as smooth witchgrass. It has a zigzag appearance as the buds turn out at the nodes. It has a very rounded stem, grows to 7’ and there is a purple tinge to its inflorescence. Sometimes it is confused with Johnson grass or barnyard grass, but fall panicum has a hairy ligule. Also its first true leaf has hairs on the underside of the blade, Johnson grass and barnyard grass do not.
Witchgrass
Panicum capillare is known as witchgrass or tickle grass. Culms are erect or spreading at the base. They are hollow, and pubescent at the nodes. They grow from 8 to 28” inches tall. The inflorescence is often ½ the length of the entire plant. It is purplish at maturity. It is softly hairy and the seeds are 1/16 of an inch. The head breaks off easily and rolls away in the wind, like a tumbleweed.
Goosegrass
Goosegrass (Elusine indica) is a prostrate-growing summer annual weed that grows in a clump. The leaves are distinctly folded in the bud and may be smooth or have a few sparse hairs at the base of the leaf. Goosegrass can be identified by the whitish stems at the base that are extremely compressed and flattened. The ligule is toothed and membranous with a cut in the center. There are no auricles. Goosegrass seed heads contain 3-7 spikes that form at the tip of the stalk. The seeds are attached in a zipper appearance on the spike. Goosegrass germinates about two weeks later than smooth crabgrass. Goosegrass can tolerate heavy traffic, dry compacted soils and low mowing heights.
Sandbur
Sandbur (Cenchrus longispinus) is a low-growing summer annual weed which is found in dense spreading patches most commonly in sandy soils. It roots at the nodes on the stems if they touch the ground. The leaves are folded in the bud, ¼ inch wide, and tapering to a point. The ligule is a short fringe of hairs and the auricles are absent. The seed head is a single spike with 6 to 20 rounded burs which contain 2 seeds in each bur. Sandbur seeds catch on clothing and animal fur and the barbed burs can easily pierce the skin and cause injury to livestock and people. Plants growing low to the ground can still produce burs. After a frost, entire plants become straw-colored, but stems with burs can persist through the winter. Seed dispersal occurs by animals, farm equipment, tires and in contaminated hay. Water is also important for seed dispersal, as burs float and may be carried for miles in irrigations ditches and other waterways.
Yellow Foxtail
Yellow foxtail (Setaria glauca) is a summer annual found especially in the Midwest and Eastern parts of the United States. It germinates when soil temperatures reach 65 degrees. Leaves are rolled in the bud. The ligule is a fringe of hairs. Auricles are absent. The collar is narrow and continuous. The blade contains hairs near the ligule. It has an upright growth pattern. The seed head is a bushy spike which resembles the tail of a fox.
BROADLEAFS
Black Medic
Black medic (Medicago lupulina) is a summer annual that can act as a perennial. The leaf is similar to other legumes, but the center leaflet is on a separate petiole. The flower is a compressed cluster of bright yellow flowers in the shape of a globular spike on short branches. The seed pod turns black at maturity. It will produce seeds at normal mowing heights. It can be confused with lespedeza (Kummerowia striata) unless it is blooming. Lespedeza has a bright blue flower.
Carpetweed
Carpetweed (Mollugo verticillata) is a summer annual with smooth prostrate branching stems forming circular mats. It is light green in color, the leaves are lanceolate in shape, widest in the middle and narrow at tip and base. Leaves form whorls containing 3-8 leaves. The flowers are white, have 5 petals, and form clusters of 2-5 flowers. Flowers are formed in the leaf axils. It spreads by seed, and is found throughout North America. Carpetweed germinates much later than other summer weeds. It grows quickly, especially in thin turf. Mowing misses it. It prefers rich moist soils, but it can establish itself in dry, sandy soil.
Lambsquarter
Lambsquarter (Chenopodium album) is an erect growing summer annual that may appear highly branched in a mowed setting. The immature leaves appear to be covered with a white mealy substance, especially on the underside of the leaf. The first pair of leaves are opposite, and subsequent leaves are alternate along the stems. Leaf margins vary, but usually are irregularly lobed. The root of lambsquarter is a short, branched taproot. The flowers are found in small green clusters and lack petals. The clusters of flowers form in terminal spikes. Lambsquarter spreads by black seeds that germinate in the late spring to early summer. Each plant produces thousands of tiny seeds that may remain viable for years. When lambsquarter is abundant, it is reported to cause hay fever symptoms.
Mallow
Mallow (Hibiscus trionum) is a summer annual-- it is also called “flower of an hour”. There is a winter annual mallow, it is usually called the common mallow. H. trionum is grown in Europe as an ornamental. It is upright 10-18”. It is covered with hairs. The leaves are deeply cleft with 3-5 coarsely toothed lobes on long petioles. The lower stems and petioles are red to purple in color. It has a fibrous root system with a weak taproot. It has a showy flower. It is light sulfur-yellow in color with a deep red to purple center. It does last 2-3 hours then the petals drop. It spreads by seed. The seed can be dormant for 50 years. It is found throughout the U.S. Mallow can infest nurseries, orchards, roadsides, cultivated fields and open areas. It tolerates drought, alkaline soil, and gravelly soils.
Pigweed
Pigweed is actually toxic to pigs and cows. This summer annual has alternate leaves. There are 10 pigweeds (Amaranthus) identified through the corn belt area: redroot, smooth, rough pigweed, Powell, tumble, prostrate, spiny, tall, sandhill and another one. The difference is in the flower. The leaves are alternate, the seeds (1/25”) are shiny, round and flat. The plant can reach 2-4’ for the smaller ones and up to 61/2’ for the larger ones.
Prostrate knotweed
Prostrate knotweed (Polygonum aviculare) is a summer annual which resembles a grass with long, dark leaves as the seedling emerges. Later, it forms a flat mat up to 2 to 3 feet in diameter on slender wiry stems that emerge from a tap root. There are papery sheath or ocrea at each node that give the stems a knotted or swollen appearance. The alternate leaves are small and narrowly oval, dull and bluish green, and 1 ¼ inches long by 1/3 inch wide. The flowers are small pink to white and form in clusters in the leaf axis. Knotweed is found in compacted, infertile soil or thin turf in the sun. Smartweed is a close relative of knotweed, but it has a purple ocrea encircling the stem. Spotted spurge may be confused with knotweed, but the spurges do not have an ocrea and emit a milky sap when cut, unlike prostrate knotweed.
Puncturevine
Puncturevine (Tribulus terrestris) is a summer annual weed with multiple stems prostrate along the ground. Stems may be up to five feet long originating from a taproot. Leaves are compound pinnate with four to eight pairs of hairy leaflets. Each leaflet is less than ½ inch long. The small yellow flowers have five petals and are about 1/3 inch wide. The flowers, which consist of 5 petals, produce hard, spiny, five-lobed fruit. Bloom is in late spring and early summer. At maturity the fruit breaks into tack-like structures each containing 2 to 4 seeds. Seed nutlets disperse by adhering to tires, shoes and clothing of people, fur, feathers, and feet of animals. These burs can injure people and animals and can damage bike and car tires. Foliage is toxic to livestock, especially sheep, when consumed in quantity. The fruit is used medicinally in India.
Purslane
Purslane (Portulaca oleracea) is a prostrate mat-forming summer annual that can reach up to 24 inches long. It has multi-branched red stems that root at the nodes wherever they contact the soil surface. The smooth, thick, fleshy leaves are usually alternate and are often clustered near the ends of the branches. The entire plant is very succulent and resembles a jade plant. Purslane is common to disturbed soil, new seedlings, sidewalk crevices and mulched planting beds. It prefers high light and warm conditions. This plant reproduces by seeds that are formed in a capsule with a lid that flips open in the spring. Solitary yellow flowers with 5 petals will only open with sunny conditions from May to September. Purslane’s use as a medicinal herb to treat dysentery, headache, and stomach ache dates back 2000 years. It was also used as a salad green by the Australian aborigines, by the Chinese, French, Italians, and the English.
Ragweed
Ragweed (Ambrosia artemisifolia) is a summer annual that produces pollen. One weed equals 1 billion grains of pollen, 100 million tons of pollen are produced per year. It grows up to 5’ tall. Opposite leaves are egg-shaped in outline and once or twice compound (pinnatified), they are hairy on their upper surface and margin. Leaves can be up to 6” long, The erect stems have long rough hairs. The fruit is an achene, which resembles a queen’s crown. It has a shallow taproot. There is a giant ragweed (Ambrosia tridida) which grows up to 14’ high. No animal eats ragweed.
Spurge
Prostrate spurge (Euphorbia supine) and spotted spurge (Euphorbia maculate) are summer annual weeds. Spotted spurge has a more erect growth habit than prostrate spurge. Prostrate spurge forms dense mats with its stems radiating out from a shallow taproot. Both species have similar leaves, which are small and oblong with an irregular maroon to purple spot in their center. However, the leaves of spotted spurge are slightly larger than those of prostrate spurge. Both spurges have leaves that grow opposite on the stem, but spotted spurge has fewer leaves per stem. When the leaves of both spurges are broken or injured they emit a milky white sap (similar to dandelion). Prostrate spurge roots at the nodes, but spotted spurge does not. Both spurges reproduce from seed. The flower of spotted spurge is small and green in color. Prostrate spurge has inconspicuous small, pinkish white flowers in the leaf axils.
Vervain
Vervain (Verbena officinalis) is known as the herb of enchantment. It is used medically in 30 complaints. Supposedly vervain staunched the wounds of Christ on the Mount of Calvary. It has a slightly bitter taste and it has no scent. Vervain is rarely perennial, the leaves are numerous, opposite, lanceolate to ovate ½ to 3” long. It is pinnately toothed, it can have 3 lobes, with the center lobe larger than the others. The leaves are hairy on both surfaces. The flower is a dense terminal spike 1-8” long, usually ascending. The flower is blue or purple with 5 lobes, the tiny flowers are almost hidden by conspicuous hairy bracts.
Integrated Pest Management Strategies for Summer Annual Weeds
1. Use good cultural practices to prevent the spread of summer annual weeds. Maintain a dense actively growing turf through proper mowing, fertilizing and watering practices. Most lawns should be cut at least 2 inches or higher. Watering deeply (4-6 inches) just before the turf begins to wilt is a sound approach. Frequent light watering promotes weak turf with shallow roots which are more susceptible to insect and disease attacks as well as weed invasion. Complete soil testing is the key to proper liming and fertilization. Cultural practices for the control of summer annual weeds are aimed at shading and crowding the young weed seedlings by producing a dense sod.
2. Dig up the weeds.
3. Coring and traffic control reduce compaction and encourage desirable turfgrass growth. Mulch flower beds to control weeds.
4. Use chemical herbicides. Use a post-emergent herbicide when the weed is young, usually three to four leaf stage. It is best to control summer annual weeds in late spring or early summer when they are young. They are easier to control at that time and both warm season and cool season turfgrasses have a greater chance to recover the areas previously occupied by weeds. There are also some pre-emergent herbicides available which form a chemical barrier in the soil and prevent the weeds from emerging. Check herbicide labels to verify that the herbicide you have chosen is effective in controlling your problem weed and when and how to apply.
GRASSES
Barnyardgrass
Barnyardgrass (Echinochloa crus-galli) is a summer annual grass that germinates from seeds from late winter or early spring throughout the summer. The stems are usually erect, thick, without hairs, often branched at the lower nodes, and may be tinted red to maroon at the base. The stems may reach 5 feet in height. The smooth, hairless leaves are rolled in the bud and contain neither ligules nor auricles. The dark green leaves, which range from 4 to 20 inches in length, have a distinct white midvein range. The seed head is green to reddish purple, with conspicuous, short stiff bristles or barbed spikelets. The roots are fibrous. Under close mowing, the broad, compressed purple sheaths of barnyardgrass lie flat on the ground and spread in a semicircular pattern. Barnyardgrass is found in moist soils, especially soils high in nutrients.
Crabgrass
Crabgrass, large and smooth (Digitaria sanguinalis, Digitaria ischaemum) are pale green summer annuals that has a prostrate or ascending growth habit. The two main species of crabgrass that occur in Missouri are smooth and large. Smooth crabgrass may be distinguished from large crabgrass by the absence of hairs on the leaves and sheath. Also smooth crabgrass does not root at the nodes like large crabgrass. Both species have a long, jagged membranous ligule and have no auricles. Crabgrass forms dense, unsightly patches that smother desirable turf grasses. Germination occurs when soil temperatures consistently reach 55 degrees F and is generally killed at the first frost. A crabgrass plant which needs warm soils and sunlight can produce 150,000 seeds. The seed head is composed of 2-6 branches (spikes) at the top of the stems forming 2 rows along the spike.
To control early in the season, use a pre-emergent herbicide as soon as soil temperatures reach 55 degrees F for a period of four days about the time forsythia blooms. A pre-emergent herbicide is recommended even if some crabgrass plants have germinated. There will still be crabgrass seed in the soil and the herbicide can prevent further infestation. Do not aerate after a pre-emergent herbicide application. For crabgrass control after germination, use a post-emergent selective grass herbicide.
Fall Panicum
Fall panicum (Panicum dichotomiflorum) is known as smooth witchgrass. It has a zigzag appearance as the buds turn out at the nodes. It has a very rounded stem, grows to 7’ and there is a purple tinge to its inflorescence. Sometimes it is confused with Johnson grass or barnyard grass, but fall panicum has a hairy ligule. Also its first true leaf has hairs on the underside of the blade, Johnson grass and barnyard grass do not.
Witchgrass
Panicum capillare is known as witchgrass or tickle grass. Culms are erect or spreading at the base. They are hollow, and pubescent at the nodes. They grow from 8 to 28” inches tall. The inflorescence is often ½ the length of the entire plant. It is purplish at maturity. It is softly hairy and the seeds are 1/16 of an inch. The head breaks off easily and rolls away in the wind, like a tumbleweed.
Goosegrass
Goosegrass (Elusine indica) is a prostrate-growing summer annual weed that grows in a clump. The leaves are distinctly folded in the bud and may be smooth or have a few sparse hairs at the base of the leaf. Goosegrass can be identified by the whitish stems at the base that are extremely compressed and flattened. The ligule is toothed and membranous with a cut in the center. There are no auricles. Goosegrass seed heads contain 3-7 spikes that form at the tip of the stalk. The seeds are attached in a zipper appearance on the spike. Goosegrass germinates about two weeks later than smooth crabgrass. Goosegrass can tolerate heavy traffic, dry compacted soils and low mowing heights.
Sandbur
Sandbur (Cenchrus longispinus) is a low-growing summer annual weed which is found in dense spreading patches most commonly in sandy soils. It roots at the nodes on the stems if they touch the ground. The leaves are folded in the bud, ¼ inch wide, and tapering to a point. The ligule is a short fringe of hairs and the auricles are absent. The seed head is a single spike with 6 to 20 rounded burs which contain 2 seeds in each bur. Sandbur seeds catch on clothing and animal fur and the barbed burs can easily pierce the skin and cause injury to livestock and people. Plants growing low to the ground can still produce burs. After a frost, entire plants become straw-colored, but stems with burs can persist through the winter. Seed dispersal occurs by animals, farm equipment, tires and in contaminated hay. Water is also important for seed dispersal, as burs float and may be carried for miles in irrigations ditches and other waterways.
Yellow Foxtail
Yellow foxtail (Setaria glauca) is a summer annual found especially in the Midwest and Eastern parts of the United States. It germinates when soil temperatures reach 65 degrees. Leaves are rolled in the bud. The ligule is a fringe of hairs. Auricles are absent. The collar is narrow and continuous. The blade contains hairs near the ligule. It has an upright growth pattern. The seed head is a bushy spike which resembles the tail of a fox.
BROADLEAFS
Black Medic
Black medic (Medicago lupulina) is a summer annual that can act as a perennial. The leaf is similar to other legumes, but the center leaflet is on a separate petiole. The flower is a compressed cluster of bright yellow flowers in the shape of a globular spike on short branches. The seed pod turns black at maturity. It will produce seeds at normal mowing heights. It can be confused with lespedeza (Kummerowia striata) unless it is blooming. Lespedeza has a bright blue flower.
Carpetweed
Carpetweed (Mollugo verticillata) is a summer annual with smooth prostrate branching stems forming circular mats. It is light green in color, the leaves are lanceolate in shape, widest in the middle and narrow at tip and base. Leaves form whorls containing 3-8 leaves. The flowers are white, have 5 petals, and form clusters of 2-5 flowers. Flowers are formed in the leaf axils. It spreads by seed, and is found throughout North America. Carpetweed germinates much later than other summer weeds. It grows quickly, especially in thin turf. Mowing misses it. It prefers rich moist soils, but it can establish itself in dry, sandy soil.
Lambsquarter
Lambsquarter (Chenopodium album) is an erect growing summer annual that may appear highly branched in a mowed setting. The immature leaves appear to be covered with a white mealy substance, especially on the underside of the leaf. The first pair of leaves are opposite, and subsequent leaves are alternate along the stems. Leaf margins vary, but usually are irregularly lobed. The root of lambsquarter is a short, branched taproot. The flowers are found in small green clusters and lack petals. The clusters of flowers form in terminal spikes. Lambsquarter spreads by black seeds that germinate in the late spring to early summer. Each plant produces thousands of tiny seeds that may remain viable for years. When lambsquarter is abundant, it is reported to cause hay fever symptoms.
Mallow
Mallow (Hibiscus trionum) is a summer annual-- it is also called “flower of an hour”. There is a winter annual mallow, it is usually called the common mallow. H. trionum is grown in Europe as an ornamental. It is upright 10-18”. It is covered with hairs. The leaves are deeply cleft with 3-5 coarsely toothed lobes on long petioles. The lower stems and petioles are red to purple in color. It has a fibrous root system with a weak taproot. It has a showy flower. It is light sulfur-yellow in color with a deep red to purple center. It does last 2-3 hours then the petals drop. It spreads by seed. The seed can be dormant for 50 years. It is found throughout the U.S. Mallow can infest nurseries, orchards, roadsides, cultivated fields and open areas. It tolerates drought, alkaline soil, and gravelly soils.
Pigweed
Pigweed is actually toxic to pigs and cows. This summer annual has alternate leaves. There are 10 pigweeds (Amaranthus) identified through the corn belt area: redroot, smooth, rough pigweed, Powell, tumble, prostrate, spiny, tall, sandhill and another one. The difference is in the flower. The leaves are alternate, the seeds (1/25”) are shiny, round and flat. The plant can reach 2-4’ for the smaller ones and up to 61/2’ for the larger ones.
Prostrate knotweed
Prostrate knotweed (Polygonum aviculare) is a summer annual which resembles a grass with long, dark leaves as the seedling emerges. Later, it forms a flat mat up to 2 to 3 feet in diameter on slender wiry stems that emerge from a tap root. There are papery sheath or ocrea at each node that give the stems a knotted or swollen appearance. The alternate leaves are small and narrowly oval, dull and bluish green, and 1 ¼ inches long by 1/3 inch wide. The flowers are small pink to white and form in clusters in the leaf axis. Knotweed is found in compacted, infertile soil or thin turf in the sun. Smartweed is a close relative of knotweed, but it has a purple ocrea encircling the stem. Spotted spurge may be confused with knotweed, but the spurges do not have an ocrea and emit a milky sap when cut, unlike prostrate knotweed.
Puncturevine
Puncturevine (Tribulus terrestris) is a summer annual weed with multiple stems prostrate along the ground. Stems may be up to five feet long originating from a taproot. Leaves are compound pinnate with four to eight pairs of hairy leaflets. Each leaflet is less than ½ inch long. The small yellow flowers have five petals and are about 1/3 inch wide. The flowers, which consist of 5 petals, produce hard, spiny, five-lobed fruit. Bloom is in late spring and early summer. At maturity the fruit breaks into tack-like structures each containing 2 to 4 seeds. Seed nutlets disperse by adhering to tires, shoes and clothing of people, fur, feathers, and feet of animals. These burs can injure people and animals and can damage bike and car tires. Foliage is toxic to livestock, especially sheep, when consumed in quantity. The fruit is used medicinally in India.
Purslane
Purslane (Portulaca oleracea) is a prostrate mat-forming summer annual that can reach up to 24 inches long. It has multi-branched red stems that root at the nodes wherever they contact the soil surface. The smooth, thick, fleshy leaves are usually alternate and are often clustered near the ends of the branches. The entire plant is very succulent and resembles a jade plant. Purslane is common to disturbed soil, new seedlings, sidewalk crevices and mulched planting beds. It prefers high light and warm conditions. This plant reproduces by seeds that are formed in a capsule with a lid that flips open in the spring. Solitary yellow flowers with 5 petals will only open with sunny conditions from May to September. Purslane’s use as a medicinal herb to treat dysentery, headache, and stomach ache dates back 2000 years. It was also used as a salad green by the Australian aborigines, by the Chinese, French, Italians, and the English.
Ragweed
Ragweed (Ambrosia artemisifolia) is a summer annual that produces pollen. One weed equals 1 billion grains of pollen, 100 million tons of pollen are produced per year. It grows up to 5’ tall. Opposite leaves are egg-shaped in outline and once or twice compound (pinnatified), they are hairy on their upper surface and margin. Leaves can be up to 6” long, The erect stems have long rough hairs. The fruit is an achene, which resembles a queen’s crown. It has a shallow taproot. There is a giant ragweed (Ambrosia tridida) which grows up to 14’ high. No animal eats ragweed.
Spurge
Prostrate spurge (Euphorbia supine) and spotted spurge (Euphorbia maculate) are summer annual weeds. Spotted spurge has a more erect growth habit than prostrate spurge. Prostrate spurge forms dense mats with its stems radiating out from a shallow taproot. Both species have similar leaves, which are small and oblong with an irregular maroon to purple spot in their center. However, the leaves of spotted spurge are slightly larger than those of prostrate spurge. Both spurges have leaves that grow opposite on the stem, but spotted spurge has fewer leaves per stem. When the leaves of both spurges are broken or injured they emit a milky white sap (similar to dandelion). Prostrate spurge roots at the nodes, but spotted spurge does not. Both spurges reproduce from seed. The flower of spotted spurge is small and green in color. Prostrate spurge has inconspicuous small, pinkish white flowers in the leaf axils.
Vervain
Vervain (Verbena officinalis) is known as the herb of enchantment. It is used medically in 30 complaints. Supposedly vervain staunched the wounds of Christ on the Mount of Calvary. It has a slightly bitter taste and it has no scent. Vervain is rarely perennial, the leaves are numerous, opposite, lanceolate to ovate ½ to 3” long. It is pinnately toothed, it can have 3 lobes, with the center lobe larger than the others. The leaves are hairy on both surfaces. The flower is a dense terminal spike 1-8” long, usually ascending. The flower is blue or purple with 5 lobes, the tiny flowers are almost hidden by conspicuous hairy bracts.
Integrated Pest Management Strategies for Summer Annual Weeds
1. Use good cultural practices to prevent the spread of summer annual weeds. Maintain a dense actively growing turf through proper mowing, fertilizing and watering practices. Most lawns should be cut at least 2 inches or higher. Watering deeply (4-6 inches) just before the turf begins to wilt is a sound approach. Frequent light watering promotes weak turf with shallow roots which are more susceptible to insect and disease attacks as well as weed invasion. Complete soil testing is the key to proper liming and fertilization. Cultural practices for the control of summer annual weeds are aimed at shading and crowding the young weed seedlings by producing a dense sod.
2. Dig up the weeds.
3. Coring and traffic control reduce compaction and encourage desirable turfgrass growth. Mulch flower beds to control weeds.
4. Use chemical herbicides. Use a post-emergent herbicide when the weed is young, usually three to four leaf stage. It is best to control summer annual weeds in late spring or early summer when they are young. They are easier to control at that time and both warm season and cool season turfgrasses have a greater chance to recover the areas previously occupied by weeds. There are also some pre-emergent herbicides available which form a chemical barrier in the soil and prevent the weeds from emerging. Check herbicide labels to verify that the herbicide you have chosen is effective in controlling your problem weed and when and how to apply.
0
0
文章
Dummer. ゛☀
2017年09月16日
Cyclamen and broad mites are microscopic mites (less than 0.02mm in length) that deform and distort the growing tips of plants that can result in stunted tips, curled leaves and lack of flowering. Cyclamen mites can be a pest of garden strawberry plants and both can be serious pests of a wide range of plants including: African violet, cyclamen, begonia, snapdragon, impatien, gerbera, ivy, and many indoor tropical plants.
Symptoms and Diagnosis
The mites are generally not detected until after they have caused significant damage and then only with the aid of a dissecting microscope. Hand lenses are usually not powerful enough to see these small mites. Mites are closely related to spiders and likewise adults have 4 pairs of legs. Larvae, however, have only 3 pairs.
Cyclamen mites are usually greenish and transparent and less than 1 mm in size. Their eggs are smooth and more apt to be found hidden in folds of plant tissue. They like to hide in buds or tips of new growth. They avoid light and prefer high humidity and cool (60 degrees F.) temperatures. Their feeding results in stunted growth with leaves generally curling upward. Leaves become stiffened and brittle (black in the case of delphiniums) and flowers are deformed or reduced.
Broad mites are smaller than cyclamen mites, broader, and are faster moving. Adult females are straw colored. Broad mites have a white stripe down their back, but the easiest way to differentiate the two may be by their eggs. Broad mites eggs have many small white bumps on them and are usually observed in more open locations. Typically adults cause deformed shoots and leaves, which usually curl downward, and reduced flowering. Bronzing or purpling of the leaves commonly occurs on the underside of leaves where the mites feed. Broad mites reproduce most prolifically at temperatures between 70 and 80 degrees F.
Lifecycle
Cyclamen mites can complete their lifecycle in only 1 to 3 weeks depending upon conditions. Adults can overwinter out of doors as far north as Canada in protected locations and complete many generations a year.
Broad mites can complete their lifecycle in only one week and also have a resting, pupal stage. They can overwinter in greenhouses or on indoor plants but is doubtful they can overwinter out or doors in Missouri. Meaning that each year new infestations out of doors develop from plants that have been overwintered indoors or from infested plants obtained from a nursery or garden center.
Integrated Pest Management
1. Dispose of infested plants. Since these mites can be difficult to control and reproduce rapidly, disposing of infested plants is often wise.
2. Sanitation. Examine newly purchases plant in the spring and reject them if they have curled or deformed tips and shoots that may be signs of mites.
3. Heat treatment. Cyclamen and broad mites are heat sensitive and can be killed if immersed in 110 degree F water for 30 minutes. These temperatures are generally low enough to cause little damage to most plants but water temperature must be maintained properly and the whole plant, pot and all, needs to be immersed. Removing heavily infested shoots first may make this process easier.
4. Treat with miticidal/ insecticidal soap or horticultural oil. To be effective the spray must completely cover the insects so apply liberally and make sure the spray reaches under leaves and into shoot tips where the mites hide.
5. Use chemical sprays. Dicofol (Kelthane) a broad-spectrum miticide can give good control. Follow label instructions.
Symptoms and Diagnosis
The mites are generally not detected until after they have caused significant damage and then only with the aid of a dissecting microscope. Hand lenses are usually not powerful enough to see these small mites. Mites are closely related to spiders and likewise adults have 4 pairs of legs. Larvae, however, have only 3 pairs.
Cyclamen mites are usually greenish and transparent and less than 1 mm in size. Their eggs are smooth and more apt to be found hidden in folds of plant tissue. They like to hide in buds or tips of new growth. They avoid light and prefer high humidity and cool (60 degrees F.) temperatures. Their feeding results in stunted growth with leaves generally curling upward. Leaves become stiffened and brittle (black in the case of delphiniums) and flowers are deformed or reduced.
Broad mites are smaller than cyclamen mites, broader, and are faster moving. Adult females are straw colored. Broad mites have a white stripe down their back, but the easiest way to differentiate the two may be by their eggs. Broad mites eggs have many small white bumps on them and are usually observed in more open locations. Typically adults cause deformed shoots and leaves, which usually curl downward, and reduced flowering. Bronzing or purpling of the leaves commonly occurs on the underside of leaves where the mites feed. Broad mites reproduce most prolifically at temperatures between 70 and 80 degrees F.
Lifecycle
Cyclamen mites can complete their lifecycle in only 1 to 3 weeks depending upon conditions. Adults can overwinter out of doors as far north as Canada in protected locations and complete many generations a year.
Broad mites can complete their lifecycle in only one week and also have a resting, pupal stage. They can overwinter in greenhouses or on indoor plants but is doubtful they can overwinter out or doors in Missouri. Meaning that each year new infestations out of doors develop from plants that have been overwintered indoors or from infested plants obtained from a nursery or garden center.
Integrated Pest Management
1. Dispose of infested plants. Since these mites can be difficult to control and reproduce rapidly, disposing of infested plants is often wise.
2. Sanitation. Examine newly purchases plant in the spring and reject them if they have curled or deformed tips and shoots that may be signs of mites.
3. Heat treatment. Cyclamen and broad mites are heat sensitive and can be killed if immersed in 110 degree F water for 30 minutes. These temperatures are generally low enough to cause little damage to most plants but water temperature must be maintained properly and the whole plant, pot and all, needs to be immersed. Removing heavily infested shoots first may make this process easier.
4. Treat with miticidal/ insecticidal soap or horticultural oil. To be effective the spray must completely cover the insects so apply liberally and make sure the spray reaches under leaves and into shoot tips where the mites hide.
5. Use chemical sprays. Dicofol (Kelthane) a broad-spectrum miticide can give good control. Follow label instructions.
0
0
文章
Dummer. ゛☀
2017年09月16日
Aphids are a very large and diverse group of insects that plague the garden especially during the beginning and end of the growing season. At least 4,000 aphid species have been identified; variations in color, size, and appearance make it impossible to generalize.
Symptoms and Diagnosis
Aphid damage may appear as pale yellow spots on leaves, leaves that are curled, puckered, or stunted, and/or distorted blossoms. Look for aphids at the beginning of the growing season. They should be especially abundant on stems and buds where nitrogen concentrations are higher. Aphids multiply more rapidly with high nitrogen levels. Another sign to look for is a sooty black layer on the leaves. Because aphids suck more plant sap than they can use, they exude honeydew onto leaf surfaces. Envied by honeybees and ants, this honeydew substance is very sweet and molds quickly.
Life Cycle
Females lay eggs toward the end of the growing season in the bark or bud scales of their favorite plant. When the eggs hatch the following spring, the nymphs are all female and are called "stem mothers". These females will give live birth to daughters without mating. Toward the end of the growing season, males are produced, mating occurs, and the eggs will again overwinter in the plant material.
Integrated Pest Management Strategies
1. Through good horticultural practices, aphids can be minimized. One step is to control the amount of nitrogen added to the garden. By using slowrelease fertilizers such as ammonium or urea-based fertilizers, compost, decomposed manure, fish emulsion, or liquid seaweed, you slow the rate at which the aphids can reproduce. Another step is to prune moderately in winter and early spring, saving the heavy pruning for midgrowing season. This prevents the aphids from destroying fresh growth in early spring. The last step is to encourage a continuum of flowers that will attract the aphids’ natural predators— ladybugs and praying mantis.
2. Try spraying the aphids off the plants with plain water, or remove them by hand with a cloth.
3. Insecticidal soap can be used, but in moderation, as it will kill beneficial insects as well as the aphids.
4. Insecticidal baits that contain boric acid can be used to control the ants, which have a symbiotic relationship with the aphids. The ants protect the aphids and get the honeydew that they ooze in return. Use caution; boric acid is toxic to people and animals. Ant barriers placed at the base of infested plants is another way to discourage ants and allow predators to attack the aphid population.
5. Silica Aerogel/Pyrethrin is a product that will dissolve the cuticle layer on the insect causing it to dehydrate and die.
6. Use chemical insecticides. Pesticides registered for use include carbaryl (Sevin), disulfoton (Disyston), malathion, bifenthrin, imidacloprid, permethrin, petroleum oil, and pyrethrins.
Symptoms and Diagnosis
Aphid damage may appear as pale yellow spots on leaves, leaves that are curled, puckered, or stunted, and/or distorted blossoms. Look for aphids at the beginning of the growing season. They should be especially abundant on stems and buds where nitrogen concentrations are higher. Aphids multiply more rapidly with high nitrogen levels. Another sign to look for is a sooty black layer on the leaves. Because aphids suck more plant sap than they can use, they exude honeydew onto leaf surfaces. Envied by honeybees and ants, this honeydew substance is very sweet and molds quickly.
Life Cycle
Females lay eggs toward the end of the growing season in the bark or bud scales of their favorite plant. When the eggs hatch the following spring, the nymphs are all female and are called "stem mothers". These females will give live birth to daughters without mating. Toward the end of the growing season, males are produced, mating occurs, and the eggs will again overwinter in the plant material.
Integrated Pest Management Strategies
1. Through good horticultural practices, aphids can be minimized. One step is to control the amount of nitrogen added to the garden. By using slowrelease fertilizers such as ammonium or urea-based fertilizers, compost, decomposed manure, fish emulsion, or liquid seaweed, you slow the rate at which the aphids can reproduce. Another step is to prune moderately in winter and early spring, saving the heavy pruning for midgrowing season. This prevents the aphids from destroying fresh growth in early spring. The last step is to encourage a continuum of flowers that will attract the aphids’ natural predators— ladybugs and praying mantis.
2. Try spraying the aphids off the plants with plain water, or remove them by hand with a cloth.
3. Insecticidal soap can be used, but in moderation, as it will kill beneficial insects as well as the aphids.
4. Insecticidal baits that contain boric acid can be used to control the ants, which have a symbiotic relationship with the aphids. The ants protect the aphids and get the honeydew that they ooze in return. Use caution; boric acid is toxic to people and animals. Ant barriers placed at the base of infested plants is another way to discourage ants and allow predators to attack the aphid population.
5. Silica Aerogel/Pyrethrin is a product that will dissolve the cuticle layer on the insect causing it to dehydrate and die.
6. Use chemical insecticides. Pesticides registered for use include carbaryl (Sevin), disulfoton (Disyston), malathion, bifenthrin, imidacloprid, permethrin, petroleum oil, and pyrethrins.
0
0
文章
Dummer. ゛☀
2017年09月16日
Rust, Puccinia heterospora, is a fungal disease that infects leaves and stems of hollyhock. Lower leaves show the condition first, and the disease progresses upward during the growing season. The extent and severity depend on weather conditions.
Symptoms and Diagnosis
First symptoms appear on the leaves as individual, yellow, circular spots about one-eighth inch in size that enlarge to one-quarter inch or more in diameter. On the underside of the leaves, swellings or blisters soon emerge within these spots. At this stage, the symptoms resemble insect or mite galls found on many other plants; however, such galls are rare on hollyhock. The swellings continue to develop and in a few more days, they release masses of reddishbrown spores, covering the entire undersurface of the leaf.
You can easily identify the disease in the field by the round pustules that are covered by loosely attached red spores. Leaves that are heavily infected eventually turn gray or tan and die. Rust spots may also occur on the stems and leaf petioles and occasionally on green flower parts.
Life Cycle
The reddish spores are easily spread by splashing water, rain, and wind. The fungus overwinters in plant debris and possibly in overwintering, living plant tissue. Symptoms will appear very early the following spring when weather conditions are favorable.
Hollyhock rust is not extremely common throughout the state. Fortunately, we can usually enjoy colorful hollyhocks in spite of the disease, though the foliage may become unattractive in wet years.
Integrated Pest Management Strategies
1. Use disease-free plants.Start plants from seeds and place them some distance from infected stock.
2. Improve air circulation. Space plants out in a dry sunny location so that moisture is quickly evaporated from the foliage.
3. Keep plants healthy. Maintain the plants in a vigorous growing condition through a good fertility program. Irrigate during dry periods but keep the foliage dry, if possible.
4.Remove infested material. Remove old plant material and bury, burn, or compost it at the end of the flowering season. Picking off the first infected leaves as they appear may also be helpful. However, this practice alone often is not successful in controlling rust.
5. Control weeds. Destroy common mallow weeds in the vicinity as they may be hosts to the rust disease and a source of hollyhock infection.
6. Use fungicides if necessary. Consider using fungicides to supplement cultural control methods. Direct the applications primarily at the lower surface of the leaves and treat at approximately 7 to 10 day intervals. Reapply if rainfall exceeds 1/2 inch during the period. Pesticides registered for use include chlorothalonil (Daconil), sulfur, mancozeb, and maneb. All are protective fungicides and prevent rather than eradicate the fungus. Start using a fungicide prior to the first sign of disease development.
Symptoms and Diagnosis
First symptoms appear on the leaves as individual, yellow, circular spots about one-eighth inch in size that enlarge to one-quarter inch or more in diameter. On the underside of the leaves, swellings or blisters soon emerge within these spots. At this stage, the symptoms resemble insect or mite galls found on many other plants; however, such galls are rare on hollyhock. The swellings continue to develop and in a few more days, they release masses of reddishbrown spores, covering the entire undersurface of the leaf.
You can easily identify the disease in the field by the round pustules that are covered by loosely attached red spores. Leaves that are heavily infected eventually turn gray or tan and die. Rust spots may also occur on the stems and leaf petioles and occasionally on green flower parts.
Life Cycle
The reddish spores are easily spread by splashing water, rain, and wind. The fungus overwinters in plant debris and possibly in overwintering, living plant tissue. Symptoms will appear very early the following spring when weather conditions are favorable.
Hollyhock rust is not extremely common throughout the state. Fortunately, we can usually enjoy colorful hollyhocks in spite of the disease, though the foliage may become unattractive in wet years.
Integrated Pest Management Strategies
1. Use disease-free plants.Start plants from seeds and place them some distance from infected stock.
2. Improve air circulation. Space plants out in a dry sunny location so that moisture is quickly evaporated from the foliage.
3. Keep plants healthy. Maintain the plants in a vigorous growing condition through a good fertility program. Irrigate during dry periods but keep the foliage dry, if possible.
4.Remove infested material. Remove old plant material and bury, burn, or compost it at the end of the flowering season. Picking off the first infected leaves as they appear may also be helpful. However, this practice alone often is not successful in controlling rust.
5. Control weeds. Destroy common mallow weeds in the vicinity as they may be hosts to the rust disease and a source of hollyhock infection.
6. Use fungicides if necessary. Consider using fungicides to supplement cultural control methods. Direct the applications primarily at the lower surface of the leaves and treat at approximately 7 to 10 day intervals. Reapply if rainfall exceeds 1/2 inch during the period. Pesticides registered for use include chlorothalonil (Daconil), sulfur, mancozeb, and maneb. All are protective fungicides and prevent rather than eradicate the fungus. Start using a fungicide prior to the first sign of disease development.
0
0
文章
Dummer. ゛☀
2017年09月16日
This creeping juniper (Juniperus) died from overwatering
Overwatering is one of the more common causes of plant problem. Heavy and poorly drained soils are susceptible to becoming waterlogged. Roots growing in waterlogged soil may die because they cannot absorb the oxygen needed to function normally. The longer the air is cut off, the greater the root damage. The dying roots decay and cannot supply the plants with nutrients and water. Damage caused by over watering is frequently misdiagnosed as pest damage. However, pest damage rarely causes roots to concentrate near the surface of the soil. Plants stressed or injured by waterlogging can become abnormally susceptible to certain fungal pathogens. Phytophthora spp. for example, cause root rot most often in soils that are periodically waterlogged.
Symptoms and Diagnosis
Plants growing in soil that is too wet suffer from a lack of oxygen which leads to the death of roots and a loss of vigor in the plant. Stunted slow growth with yellowing leaves is a symptom of over watering. Plants may suffer from leaf scorch or leaf burn. Water soaked spots and blisters (Oedema) may appear on stems and leaves. The crown of the plant may rot. Damaged roots have little defense against the entrance of rot causing soil organisms. And so the plant dies of root rot.
Integrated Pest Management Strategies
1. Deep watering encourages roots to go deep down in the soil to where it is moist and a lot cooler. Water less frequently but for longer periods, so water reaches deep into soil. Good thorough watering promotes healthier plants.
2. Investigate using water conserving drip emitters or soaker hoses on a timer. Adjust watering frequency and amounts based on season, temperature and amount of rainfall. Overhead watering uses more water and can promote fungal disease. Also make sure you don't have leaking irrigation pipes or downspouts that are keeping the soil too wet in a location.
3. Add mulch to individual plants or beds. Add organic matter such as compost or rotted manure to plantings ---organic matter can improve drainage in heavy clay soils. Take care to keep mulch away from stems.
4. Use appropriate plants. Evaluate your site for new plantings. Choose plants with the appropriate water and cultural needs that will thrive on your site. Use water loving plants for moist poorly drained soils. Also consider native plants, which generally adapt better, have lower water demands and fewer pest problems.
5. Water only when necessary. Most plants will normally wilt in hot sun and may recover on their own later in the day as the sun moves. Make sure soil is not too wet based on the needs of particular plants before watering; you may end up by over watering.
6. A dry surface is not always a sign of water need. The surface generally dries out first and is not a true indicator of what is going on down deep near the plant root. Make use of a hand trowel or soil probe to check for moisture. Check for overwatering by digging into root zone or knocking a small potted plant out of its container. Soil that has been too long without oxygen usually smells sour or rotten.
7. Give priority to watering newly planted trees and shrubs. Young plants have not had sufficient time to establish deep root systems, and depend on surface water for survival. Do not let the root balls of newly planted trees and shrubs dry out completely or become too saturated. Before watering use a soil probe or a hand trowel. Remember that when plants are fully established, they will require less water.
Overwatering is one of the more common causes of plant problem. Heavy and poorly drained soils are susceptible to becoming waterlogged. Roots growing in waterlogged soil may die because they cannot absorb the oxygen needed to function normally. The longer the air is cut off, the greater the root damage. The dying roots decay and cannot supply the plants with nutrients and water. Damage caused by over watering is frequently misdiagnosed as pest damage. However, pest damage rarely causes roots to concentrate near the surface of the soil. Plants stressed or injured by waterlogging can become abnormally susceptible to certain fungal pathogens. Phytophthora spp. for example, cause root rot most often in soils that are periodically waterlogged.
Symptoms and Diagnosis
Plants growing in soil that is too wet suffer from a lack of oxygen which leads to the death of roots and a loss of vigor in the plant. Stunted slow growth with yellowing leaves is a symptom of over watering. Plants may suffer from leaf scorch or leaf burn. Water soaked spots and blisters (Oedema) may appear on stems and leaves. The crown of the plant may rot. Damaged roots have little defense against the entrance of rot causing soil organisms. And so the plant dies of root rot.
Integrated Pest Management Strategies
1. Deep watering encourages roots to go deep down in the soil to where it is moist and a lot cooler. Water less frequently but for longer periods, so water reaches deep into soil. Good thorough watering promotes healthier plants.
2. Investigate using water conserving drip emitters or soaker hoses on a timer. Adjust watering frequency and amounts based on season, temperature and amount of rainfall. Overhead watering uses more water and can promote fungal disease. Also make sure you don't have leaking irrigation pipes or downspouts that are keeping the soil too wet in a location.
3. Add mulch to individual plants or beds. Add organic matter such as compost or rotted manure to plantings ---organic matter can improve drainage in heavy clay soils. Take care to keep mulch away from stems.
4. Use appropriate plants. Evaluate your site for new plantings. Choose plants with the appropriate water and cultural needs that will thrive on your site. Use water loving plants for moist poorly drained soils. Also consider native plants, which generally adapt better, have lower water demands and fewer pest problems.
5. Water only when necessary. Most plants will normally wilt in hot sun and may recover on their own later in the day as the sun moves. Make sure soil is not too wet based on the needs of particular plants before watering; you may end up by over watering.
6. A dry surface is not always a sign of water need. The surface generally dries out first and is not a true indicator of what is going on down deep near the plant root. Make use of a hand trowel or soil probe to check for moisture. Check for overwatering by digging into root zone or knocking a small potted plant out of its container. Soil that has been too long without oxygen usually smells sour or rotten.
7. Give priority to watering newly planted trees and shrubs. Young plants have not had sufficient time to establish deep root systems, and depend on surface water for survival. Do not let the root balls of newly planted trees and shrubs dry out completely or become too saturated. Before watering use a soil probe or a hand trowel. Remember that when plants are fully established, they will require less water.
0
0
文章
Dummer. ゛☀
2017年09月16日
Hail can severely damage all plants. The severity of the damage depends on the size of the hailstones and the time of the year that the hailstorm occurs. The later in the growing season that hail damage occurs the less time plants have to recover and store energy for the winter.
Symptoms and Diagnosis
On annuals and perennials leaves, stems and flowers may be shredded, torn and knocked off. On trees and shrubs leaves, twigs and branches may be tattered, split and broken. Fruit may be pitted and knocked to the ground. The scars from hail damage to trees occur on the upper side of branches and on the side of the trunk facing the storm. The tree may take a very long time to recover. The damage increases the vulnerability of the tree to decay causing fungi and insect activity.
Integrated Pest Management Strategies
1. Evaluate damage. Assess the damage to the plants and estimate how long they have left to recover from the damage before the onset of winter.
2. Cleanup. Severely damaged trees and shrubs with broken branches should have them removed promptly. Less severe wounds may slowly heal naturally over a period of time. Damaged fruit should be removed. Do not fertilize hail damaged trees.
3. Fertilize. If the damage is early in the growing season, annuals and perennials may benefit from a light application of fertilizer. Immediately remove any damaged leaves from these plants.
4. Replace. Annuals and perennials that do not show signs of recovery within a week should be replaced with new plants.
5. Give good after care. Water the damaged plants during the growing season giving them at least one inch of water each week.
6. Mulch. Applying two to three inches of mulch around the base of damaged plants may help them survive during the winter.
Symptoms and Diagnosis
On annuals and perennials leaves, stems and flowers may be shredded, torn and knocked off. On trees and shrubs leaves, twigs and branches may be tattered, split and broken. Fruit may be pitted and knocked to the ground. The scars from hail damage to trees occur on the upper side of branches and on the side of the trunk facing the storm. The tree may take a very long time to recover. The damage increases the vulnerability of the tree to decay causing fungi and insect activity.
Integrated Pest Management Strategies
1. Evaluate damage. Assess the damage to the plants and estimate how long they have left to recover from the damage before the onset of winter.
2. Cleanup. Severely damaged trees and shrubs with broken branches should have them removed promptly. Less severe wounds may slowly heal naturally over a period of time. Damaged fruit should be removed. Do not fertilize hail damaged trees.
3. Fertilize. If the damage is early in the growing season, annuals and perennials may benefit from a light application of fertilizer. Immediately remove any damaged leaves from these plants.
4. Replace. Annuals and perennials that do not show signs of recovery within a week should be replaced with new plants.
5. Give good after care. Water the damaged plants during the growing season giving them at least one inch of water each week.
6. Mulch. Applying two to three inches of mulch around the base of damaged plants may help them survive during the winter.
0
0
文章
Dummer. ゛☀
2017年09月15日
Narrow brown, white or opaque snaking trails in leaves often with round blistered patches. There may be clusters of white dots on leaves where the adults have been feeding.
Plants affected
A wide range of vegetable crops growing indoors or outdoors, especially tomatoes and peppers.
About Leaf miner flies
There are many species of leaf miner flies in the UK.
Adults are usually small, dark-coloured flies around 5mm long.
Some of the more destructive species have a characteristic yellow spot on their backs, and others have dark-patterned wings.
Eggs are laid on or into the upper or lower surfaces of leaves and hatch about a week later.
Larvae are grubs about 1cm long, usually white in colour, and feed on the tissue between the leaf surfaces. This creates the distinctive mined trails across the leaf surface.
As larvae grow the mined trails become wider.
Larvae feed for two to three weeks before pupating.
Pupation sites vary with species, either within or on leaves, or in the soil.
Some species over-winter as pupae whereas others feed continuously until spring.
There may be one or many generations per year depending on the species.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Leaf miner flies
Methiocarb
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Regularly inspect plants all year round.
Remove and destroy infested leaves.
Crush larvae at the end of tunnels in leaves by hand.
In greenhouses, release the parasitic wasps Dacnusa sibirica and Diglyphus isaea.
Prevention
Remove any heavily infested plants.
Hang yellow sticky traps to monitor the fist sign of the flies.
Encourage insectivorous birds by hanging bird boxes and feeders.
Keep weeds under control, particularly groundsel and sowthistle as these are wild hosts.
Plants affected
A wide range of vegetable crops growing indoors or outdoors, especially tomatoes and peppers.
About Leaf miner flies
There are many species of leaf miner flies in the UK.
Adults are usually small, dark-coloured flies around 5mm long.
Some of the more destructive species have a characteristic yellow spot on their backs, and others have dark-patterned wings.
Eggs are laid on or into the upper or lower surfaces of leaves and hatch about a week later.
Larvae are grubs about 1cm long, usually white in colour, and feed on the tissue between the leaf surfaces. This creates the distinctive mined trails across the leaf surface.
As larvae grow the mined trails become wider.
Larvae feed for two to three weeks before pupating.
Pupation sites vary with species, either within or on leaves, or in the soil.
Some species over-winter as pupae whereas others feed continuously until spring.
There may be one or many generations per year depending on the species.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Leaf miner flies
Methiocarb
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Regularly inspect plants all year round.
Remove and destroy infested leaves.
Crush larvae at the end of tunnels in leaves by hand.
In greenhouses, release the parasitic wasps Dacnusa sibirica and Diglyphus isaea.
Prevention
Remove any heavily infested plants.
Hang yellow sticky traps to monitor the fist sign of the flies.
Encourage insectivorous birds by hanging bird boxes and feeders.
Keep weeds under control, particularly groundsel and sowthistle as these are wild hosts.
0
0
文章
Dummer. ゛☀
2017年09月15日
Found in all apple-growing areas of the world, the codling moth (Cydia pomonella) is considered to be one of the most destructive pests of apples. Adults are gray to brown moths with a 3/4 inch wingspan. They have a chocolate-colored patch at the tip of each forewing and coppery transverse markings.
Codling moth larvae are pink or creamy white caterpillars with mottled brown heads that tunnel through apples directly to the core. As they feed, they push out mounds of fecal material, called frass, which gathers around the entrance hole. Damage lowers the market value of the fruit and makes it unfit for human consumption. Alternate host plants include pears, crabapples, walnuts and stone fruits.
Note: The codling moth was introduced to North America by the colonists more than 200 years ago and is now one of the leading pests in home orchards.
Life Cycle
Full grown larvae pass through the winter in a cocoon beneath loose bark or in orchard litter. Pupation takes place in the spring. Moths begin emerging about the time that apple trees are in bloom and lay an average of 50 to 60 eggs on leaves, twigs and fruits. Once eggs hatch the larvae feed briefly on leaves, then damage fruit by boring into the centers. Larvae feed for three weeks, then leave to seek a suitable place to spin cocoons. There are two generations per year.
Control
Scrape loose bark in early spring to remove overwintering cocoons and then spray All Seasons® horticultural oil to eradicate eggs and first generation early instar stages.
Beneficial nematodes are microscopic, worm-like parasites that actively hunt, penetrate and destroy immature stages of this pest. Spray on trunks and main branches, and also over the soil out to the drip line for a 60% to 90% mortality in pre-pupae.
Use pheromone traps to determine the peak flight period for moths, then release trichogramma wasps to attack eggs. Pheromone traps will also help reduce male moths where populations are low and trees are isolated.
Surround WP — a wettable kaolin clay — can be used to deter a broad range of fruit tree pests (and diseases), and will reduce codling moth damage by 50-60%. Apply before moths arrive and continue for 6-8 weekly applications, or until the infestation is over.
In areas of severe infestation, spray plant-derived insecticides when 75% of petals have fallen, followed by three sprays at 1-2 week intervals. These natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
Codling moth larvae are pink or creamy white caterpillars with mottled brown heads that tunnel through apples directly to the core. As they feed, they push out mounds of fecal material, called frass, which gathers around the entrance hole. Damage lowers the market value of the fruit and makes it unfit for human consumption. Alternate host plants include pears, crabapples, walnuts and stone fruits.
Note: The codling moth was introduced to North America by the colonists more than 200 years ago and is now one of the leading pests in home orchards.
Life Cycle
Full grown larvae pass through the winter in a cocoon beneath loose bark or in orchard litter. Pupation takes place in the spring. Moths begin emerging about the time that apple trees are in bloom and lay an average of 50 to 60 eggs on leaves, twigs and fruits. Once eggs hatch the larvae feed briefly on leaves, then damage fruit by boring into the centers. Larvae feed for three weeks, then leave to seek a suitable place to spin cocoons. There are two generations per year.
Control
Scrape loose bark in early spring to remove overwintering cocoons and then spray All Seasons® horticultural oil to eradicate eggs and first generation early instar stages.
Beneficial nematodes are microscopic, worm-like parasites that actively hunt, penetrate and destroy immature stages of this pest. Spray on trunks and main branches, and also over the soil out to the drip line for a 60% to 90% mortality in pre-pupae.
Use pheromone traps to determine the peak flight period for moths, then release trichogramma wasps to attack eggs. Pheromone traps will also help reduce male moths where populations are low and trees are isolated.
Surround WP — a wettable kaolin clay — can be used to deter a broad range of fruit tree pests (and diseases), and will reduce codling moth damage by 50-60%. Apply before moths arrive and continue for 6-8 weekly applications, or until the infestation is over.
In areas of severe infestation, spray plant-derived insecticides when 75% of petals have fallen, followed by three sprays at 1-2 week intervals. These natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
0
0
文章
Dummer. ゛☀
2017年09月15日
Found in warmer growing climates, mealybugs are soft-bodied, wingless insects that often appear as white cottony masses on the leaves, stems and fruit of plants. They feed by inserting long sucking mouthparts, called stylets, into plants and drawing sap out of the tissue. Damage is not often significant at low pest levels. However, at higher numbers they can cause leaf yellowing and curling as the plant weakens. Feeding is usually accompanied by honeydew, which makes the plant sticky and encourages the growth of sooty moulds. Mealybugs are a common greenhouse pest that affect ornamentals, houseplants, avocados and fruits.
Adults (1/10 — 1/4 inch long) are soft, oval distinctly segmented insects that are usually covered with a white or gray mealy wax. Small nymphs, called crawlers, are light yellow and free of wax. They are active early on, but move little once a suitable feeding site is found.
Note: There are approximately 275 species of mealybugs known to occur throughout the United States.
Life Cycle
Adult females deposit 300-600 eggs within an excreted, compact, waxy cottony-appearing mass mostly found on the underside of leaves (these egg cases can be confused with downy mildew). Egg laying is continues for about 2 weeks with the female dying shortly after all eggs are laid. Hatching occurs within 1-3 weeks and the small active yellow nymphs begin migrating over the plant in search of feeding sites on which to settle. As they feed, they secrete honeydew and a waxy coating begins to form over their bodies. Female nymphs pass through three stages (instars) with a generation taking as little as one month, depending on temperature. Male nymphs pass through five instars. They do not feed after the first two instars and exist solely to fertilize the females. In the greenhouse, continuous and overlapping generations occur throughout the year. There is little winter survival outside of greenhouses in the North.
Mealybug Control
Prune out light infestations or dab insects with a Q-tip dipped in rubbing alcohol.
Do not over water or overfertilize — mealybugs are attracted to plants with high nitrogen levels and soft growth.
Commercially available beneficial insects, such as ladybugs, lacewing and the Mealybug Destroyer (Cryptolaemus montrouzieri), are important natural predators of this pest.
Use the Bug Blaster to hose off plants with a strong stream of water and reduce pest numbers. Washing foliage regularly with a leaf shine — made from neem oil — will help discourage future infestations.
Safer® Insecticidal Soap will work fast on heavy infestations. A short-lived natural pesticide, it works by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours. Apply 2.5 oz/ gallon of water when insects are present, repeat every 7-10 day as needed.
Neem oil disrupts the growth and development of pest insects and has repellent and anti-feedant properties. Best of all, it’s non-toxic to honey bees and many other beneficial insects. Mix 1 oz/ gallon of water and spray every 7-14 days, as needed.
Fast-acting botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
Washing foliage regularly with a leaf shine will help discourage future infestations.
Adults (1/10 — 1/4 inch long) are soft, oval distinctly segmented insects that are usually covered with a white or gray mealy wax. Small nymphs, called crawlers, are light yellow and free of wax. They are active early on, but move little once a suitable feeding site is found.
Note: There are approximately 275 species of mealybugs known to occur throughout the United States.
Life Cycle
Adult females deposit 300-600 eggs within an excreted, compact, waxy cottony-appearing mass mostly found on the underside of leaves (these egg cases can be confused with downy mildew). Egg laying is continues for about 2 weeks with the female dying shortly after all eggs are laid. Hatching occurs within 1-3 weeks and the small active yellow nymphs begin migrating over the plant in search of feeding sites on which to settle. As they feed, they secrete honeydew and a waxy coating begins to form over their bodies. Female nymphs pass through three stages (instars) with a generation taking as little as one month, depending on temperature. Male nymphs pass through five instars. They do not feed after the first two instars and exist solely to fertilize the females. In the greenhouse, continuous and overlapping generations occur throughout the year. There is little winter survival outside of greenhouses in the North.
Mealybug Control
Prune out light infestations or dab insects with a Q-tip dipped in rubbing alcohol.
Do not over water or overfertilize — mealybugs are attracted to plants with high nitrogen levels and soft growth.
Commercially available beneficial insects, such as ladybugs, lacewing and the Mealybug Destroyer (Cryptolaemus montrouzieri), are important natural predators of this pest.
Use the Bug Blaster to hose off plants with a strong stream of water and reduce pest numbers. Washing foliage regularly with a leaf shine — made from neem oil — will help discourage future infestations.
Safer® Insecticidal Soap will work fast on heavy infestations. A short-lived natural pesticide, it works by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours. Apply 2.5 oz/ gallon of water when insects are present, repeat every 7-10 day as needed.
Neem oil disrupts the growth and development of pest insects and has repellent and anti-feedant properties. Best of all, it’s non-toxic to honey bees and many other beneficial insects. Mix 1 oz/ gallon of water and spray every 7-14 days, as needed.
Fast-acting botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
Washing foliage regularly with a leaf shine will help discourage future infestations.
0
0
