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.
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0
文章
Dummer. ゛☀
2017年09月15日
Small silver patches and black dots on the leaves. Feeding thrips can also turn petals on flowers brown. New growth can be distorted, browning and curled.
Plants affected
Virtually all garden plants can be affected, from ornamental species, to fruit, vegetable, and cereal crops. Flowers and leaves of plants are most affected.
About Thrips
Thrips are sometimes known as thunderflies or thunderbugs.
There are over 3000 recorded species worldwide, with over 150 in the UK.
They are typically small, slender, dark-coloured insects about 2mm long or less and usually have two pairs of feather-like wings.
Thrips rasp through upper leaf cells to feed on plant sap, causing a silvering appearance.
Thrip droppings are minute black specks on the leaves.
Thrips have six lifecycle stages including egg, larvae, pupa and adult.
Larvae and pupae can be a lighter colour than adults.
Females have a serrated tube for laying eggs into plant tissue.
They are predominantly a summer pest, favouring warm temperatures and dry conditions.
Thundery conditions trigger swarming.
Some species can transmit viruses such as tomato spotted wilt virus.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Thrips
Pyrethrins
Methiocarb
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Release the predatory mite Amblyseius cucumeris, and predatory bug Orius laevigatus.
Spray organic plant oils approved for use on plants.
Remove and destroy infested leaves, particularly silvery areas where eggs are present.
Prevention
Thoroughly clean greenhouses at the end of the season to remove any over-wintering thrips.
Use sticky traps to monitor the first appearance of thrips. Blue coloured traps are thought to be more effective than other colours.
Netting and fleeces can be used as a barrier between plants.
Plants affected
Virtually all garden plants can be affected, from ornamental species, to fruit, vegetable, and cereal crops. Flowers and leaves of plants are most affected.
About Thrips
Thrips are sometimes known as thunderflies or thunderbugs.
There are over 3000 recorded species worldwide, with over 150 in the UK.
They are typically small, slender, dark-coloured insects about 2mm long or less and usually have two pairs of feather-like wings.
Thrips rasp through upper leaf cells to feed on plant sap, causing a silvering appearance.
Thrip droppings are minute black specks on the leaves.
Thrips have six lifecycle stages including egg, larvae, pupa and adult.
Larvae and pupae can be a lighter colour than adults.
Females have a serrated tube for laying eggs into plant tissue.
They are predominantly a summer pest, favouring warm temperatures and dry conditions.
Thundery conditions trigger swarming.
Some species can transmit viruses such as tomato spotted wilt virus.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Thrips
Pyrethrins
Methiocarb
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Release the predatory mite Amblyseius cucumeris, and predatory bug Orius laevigatus.
Spray organic plant oils approved for use on plants.
Remove and destroy infested leaves, particularly silvery areas where eggs are present.
Prevention
Thoroughly clean greenhouses at the end of the season to remove any over-wintering thrips.
Use sticky traps to monitor the first appearance of thrips. Blue coloured traps are thought to be more effective than other colours.
Netting and fleeces can be used as a barrier between plants.
0
0
文章
Dummer. ゛☀
2017年09月15日
Yellowing or reddening of leaves, discoloured or aborting fruits and flowers, and poor plant growth. Fruits can become misshapen and display brown leathery patches.
Plants affected
All plants can be affected.
About Nutrient deficiency
In order to develop and complete their life-cycle without sustaining damage to new growth, flowers or fruit, plants require nutrients.
To maximise efficiency, nutrient supply to plants should be balanced to meet individual needs.
The main nutrients required are carbon, nitrogen, oxygen, hydrogen, phosphorous and potassium.
In addition to these, a number of less essential nutrients known as secondary nutrients are used by a plant to optimise its growth.
There are also many micro nutrients used in tiny amounts by specific plant species.
Main nutrients contribute to production of chlorophyll, fruit set and yield, defence against adverse environmental conditions, leaf loss, and certain diseases. They also aid in the healthy growth of roots, leaves and flowers.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Nutrient deficiency
Nitrogen, potassium and phosphorous fertilisers.
Calcium ammonium nitrate
Ammonium nitrate
Urea
Potassium chloride
Potassium sulphate
Calcium carbonate
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Incorporating farmyard manure, composted plant material, leaf mould and other natural sources of nutrients will ensure healthy plant growth.
Prevention
Establish a regular feeding programme for all potted and hanging basket plants, and those grown in a greenhouse.
Apply a suitable liquid feed to your garden plants at regular intervals when watering.
Apply a suitable granular feed to your lawn at seasonal intervals as indicated.
Incorporate slow release fertiliser granules into all compost used for potting plants.
Dig sources of plant nutrients such as garden compost or well-rotted manure into flower beds and vegetable patches, or place around the bases of existing plants.
Scarify, top-dress, and aerate lawns at the beginning and end of growing seasons.
Plants affected
All plants can be affected.
About Nutrient deficiency
In order to develop and complete their life-cycle without sustaining damage to new growth, flowers or fruit, plants require nutrients.
To maximise efficiency, nutrient supply to plants should be balanced to meet individual needs.
The main nutrients required are carbon, nitrogen, oxygen, hydrogen, phosphorous and potassium.
In addition to these, a number of less essential nutrients known as secondary nutrients are used by a plant to optimise its growth.
There are also many micro nutrients used in tiny amounts by specific plant species.
Main nutrients contribute to production of chlorophyll, fruit set and yield, defence against adverse environmental conditions, leaf loss, and certain diseases. They also aid in the healthy growth of roots, leaves and flowers.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Nutrient deficiency
Nitrogen, potassium and phosphorous fertilisers.
Calcium ammonium nitrate
Ammonium nitrate
Urea
Potassium chloride
Potassium sulphate
Calcium carbonate
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Incorporating farmyard manure, composted plant material, leaf mould and other natural sources of nutrients will ensure healthy plant growth.
Prevention
Establish a regular feeding programme for all potted and hanging basket plants, and those grown in a greenhouse.
Apply a suitable liquid feed to your garden plants at regular intervals when watering.
Apply a suitable granular feed to your lawn at seasonal intervals as indicated.
Incorporate slow release fertiliser granules into all compost used for potting plants.
Dig sources of plant nutrients such as garden compost or well-rotted manure into flower beds and vegetable patches, or place around the bases of existing plants.
Scarify, top-dress, and aerate lawns at the beginning and end of growing seasons.
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文章
Dummer. ゛☀
2017年09月15日
When attacks are severe, foliage will be peppered with small holes and pits, and growth may be reduced. The tissue around damaged areas will become dry and discoloured.
Plants affected
Many plants from the Brassica family are attacked, as well as a small number of ornamentals.
About
Adult beetles are up to 3mm long, usually shiny black in colour and may have light coloured stripes down their wing casing.
Larvae are small white coloured grubs with brown heads and pairs of fleshy legs.
Eggs are tiny opaque yellow elliptical forms, and are laid around plant roots.
Adults usually have long, hinged hind legs that enable them to jump like fleas.
Over-wintering takes place as adults, either beneath the soil surface or amongst plant debris around the base of the plant.
Adults re-emerge in early spring to feed and mate.
During dry periods in April/May, feeding can be severe and may result in plants dying. During this time adults can be seen jumping on and around infested plants.
Eggs are laid towards the end of May/ early June, and will hatch a few days later.
The larvae will begin to feed immediately after hatching. Mainly on plant roots, although some larvae feed on leaves.
Pupation occurs in late summer, with second generation adults emerging during autumn.
Treatment
Chemical
Rotenone
Pyrethrins
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Fleeces can be used to protect new seedlings from infestation.
Encourage insectivorous birds by hanging boxes and feeders.
Use yellow sticky traps to catch adults.
Prevention
Flea beetles prefer dry conditions, so keep plants well watered.
Remove all plant debris from the base of your plants, to reduce over-wintering sites.
Try “trap planting” by growing more susceptible hosts between your primary plants.
Plants affected
Many plants from the Brassica family are attacked, as well as a small number of ornamentals.
About
Adult beetles are up to 3mm long, usually shiny black in colour and may have light coloured stripes down their wing casing.
Larvae are small white coloured grubs with brown heads and pairs of fleshy legs.
Eggs are tiny opaque yellow elliptical forms, and are laid around plant roots.
Adults usually have long, hinged hind legs that enable them to jump like fleas.
Over-wintering takes place as adults, either beneath the soil surface or amongst plant debris around the base of the plant.
Adults re-emerge in early spring to feed and mate.
During dry periods in April/May, feeding can be severe and may result in plants dying. During this time adults can be seen jumping on and around infested plants.
Eggs are laid towards the end of May/ early June, and will hatch a few days later.
The larvae will begin to feed immediately after hatching. Mainly on plant roots, although some larvae feed on leaves.
Pupation occurs in late summer, with second generation adults emerging during autumn.
Treatment
Chemical
Rotenone
Pyrethrins
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Fleeces can be used to protect new seedlings from infestation.
Encourage insectivorous birds by hanging boxes and feeders.
Use yellow sticky traps to catch adults.
Prevention
Flea beetles prefer dry conditions, so keep plants well watered.
Remove all plant debris from the base of your plants, to reduce over-wintering sites.
Try “trap planting” by growing more susceptible hosts between your primary plants.
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文章
Dummer. ゛☀
2017年09月15日
Distorted, yellowing or slowed growth on plants can often be a sign of scale insects. These look like tiny brown or orange blobs and can often be found on the undersides of the leaves near the veins, on the stems or in the leaf joints. They produce sticky honeydew as they feed which can cause the foliage on infested plants to become sticky and covered with dark sooty mould.
Plants affected
Scales are usually pests of ornamental plants and can be especially troublesome in greenhouses. Over 300 species of ornamental plants are known hosts.
About Scale insects
Scale insects are small sap-sucking insects, so called because they produce an umbrella-like waxy coating or 'scale' over their soft bodies.
They're often difficult to detect on plants, although leaf yellowing or sticky honeydew deposits can be the first signs of infestation.
Scale insects may appear as small, flattened white, yellow or brown 'discs' or 'blobs', on stems or on the underside of leaves near the veins.
Scale insects are divided into two families - soft scale (Coccidae) and hard scale (Diaspididae).
Soft scales can breed all year round on protected crops and produce large amounts of sugary honeydew when they feed on the plant's sap. This honeydew attracts sooty moulds that grow on the leaves.
Hard scales lay eggs under their scales which hatch into nymphs or 'crawlers' after the female dies in early summer.
The nymphs can move short distances on a plant, but disperse long distances on the wind or on animals.
Hard scale don't produce large amounts of honeydew.
Female scale insect nymphs become immobile once they find a suitable feeding site and become adults.
Males are rarely seen but are often winged and midge-like in appearance.
The 'scale' produced by these insects can remain on a plant for a long time after they're dead.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Scale insects
Pyrethrum
Natural fatty acids
Rape seed oil
Tar oil wash (for use on deciduous trees and roses in December)
Thiacloprid (for use with outdoor fruit crops)
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Check bought plants thoroughly. If an infestation is in the early stages, the scales can be cleaned off using a brush and water, or just a thumbnail.
Biological control is available in the form of a tiny wasp which parasitises soft scales, Metaphycus helvolus. This can be purchased for release into the greenhouse but requires good light and temperatures of at least 22°C (72°F) to be effective.
The small predatory ladybird Chilocorus nigritus can also be purchased, that feeds on hard scale species. Lacewing larvae also control scale.
Prevention
Check plants regularly for signs of scale infestation and deal with them as soon as they appear.
Keep the environment clear of weeds because these often harbour the pest.
Monitor plants for signs of scale, such as leaf drop, honeydew or sooty mould.
Look out for ants running up and down the plants, 'milking' the honeydew.
Avoid using broad spectrum insecticides which will kill beneficial insects as well as scale.
Destroy any leaves that have been removed from an infested plant because these can harbour many mobile juvenile scales.
Plants affected
Scales are usually pests of ornamental plants and can be especially troublesome in greenhouses. Over 300 species of ornamental plants are known hosts.
About Scale insects
Scale insects are small sap-sucking insects, so called because they produce an umbrella-like waxy coating or 'scale' over their soft bodies.
They're often difficult to detect on plants, although leaf yellowing or sticky honeydew deposits can be the first signs of infestation.
Scale insects may appear as small, flattened white, yellow or brown 'discs' or 'blobs', on stems or on the underside of leaves near the veins.
Scale insects are divided into two families - soft scale (Coccidae) and hard scale (Diaspididae).
Soft scales can breed all year round on protected crops and produce large amounts of sugary honeydew when they feed on the plant's sap. This honeydew attracts sooty moulds that grow on the leaves.
Hard scales lay eggs under their scales which hatch into nymphs or 'crawlers' after the female dies in early summer.
The nymphs can move short distances on a plant, but disperse long distances on the wind or on animals.
Hard scale don't produce large amounts of honeydew.
Female scale insect nymphs become immobile once they find a suitable feeding site and become adults.
Males are rarely seen but are often winged and midge-like in appearance.
The 'scale' produced by these insects can remain on a plant for a long time after they're dead.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Scale insects
Pyrethrum
Natural fatty acids
Rape seed oil
Tar oil wash (for use on deciduous trees and roses in December)
Thiacloprid (for use with outdoor fruit crops)
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Check bought plants thoroughly. If an infestation is in the early stages, the scales can be cleaned off using a brush and water, or just a thumbnail.
Biological control is available in the form of a tiny wasp which parasitises soft scales, Metaphycus helvolus. This can be purchased for release into the greenhouse but requires good light and temperatures of at least 22°C (72°F) to be effective.
The small predatory ladybird Chilocorus nigritus can also be purchased, that feeds on hard scale species. Lacewing larvae also control scale.
Prevention
Check plants regularly for signs of scale infestation and deal with them as soon as they appear.
Keep the environment clear of weeds because these often harbour the pest.
Monitor plants for signs of scale, such as leaf drop, honeydew or sooty mould.
Look out for ants running up and down the plants, 'milking' the honeydew.
Avoid using broad spectrum insecticides which will kill beneficial insects as well as scale.
Destroy any leaves that have been removed from an infested plant because these can harbour many mobile juvenile scales.
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文章
Dummer. ゛☀
2017年09月15日
Distorted and misshapen leaves, flowers, buds and fruit growth. The leaf tissue around affected areas may become brown and eventually die.
Plants affected
Many different garden plants are affected including fruits, vegetables, ornamentals, trees and weeds.
About Capsid bugs
Capsid bugs feed on plant sap and in doing so cause deformation of plant material.
There are many different species of capsid bugs in the UK.
Capsids are also known as mirid bugs.
Some species of capsid also feed on other small insects.
Adults vary in colour from green to red/ brown, around 6mm in length, and have a long, slender feeding tube.
Young are similar in shape and colour, but smaller and wingless.
When disturbed they fall down onto the soil as a defence.
When feeding they inject saliva which is toxic to plants.
There can be one or two generations per year depending on the species.
Eggs are laid into cracks in tree bark, woody stems, and at the base of hedges. They hatch in late spring.
Depending on species, over-wintering takes place as eggs or as adults in plant debris.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Capsid bugs
Pyrethrins
Pyrethroids
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 in spring.
Remove and destroy adults by hand.
Winter wash trees to destroy eggs.
Prevention
Keep areas around plants free from plant debris.
Remove weeds around plants.
Plants affected
Many different garden plants are affected including fruits, vegetables, ornamentals, trees and weeds.
About Capsid bugs
Capsid bugs feed on plant sap and in doing so cause deformation of plant material.
There are many different species of capsid bugs in the UK.
Capsids are also known as mirid bugs.
Some species of capsid also feed on other small insects.
Adults vary in colour from green to red/ brown, around 6mm in length, and have a long, slender feeding tube.
Young are similar in shape and colour, but smaller and wingless.
When disturbed they fall down onto the soil as a defence.
When feeding they inject saliva which is toxic to plants.
There can be one or two generations per year depending on the species.
Eggs are laid into cracks in tree bark, woody stems, and at the base of hedges. They hatch in late spring.
Depending on species, over-wintering takes place as eggs or as adults in plant debris.
Treatment
Chemical
Products containing the following chemical ingredients are all effective on Capsid bugs
Pyrethrins
Pyrethroids
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 in spring.
Remove and destroy adults by hand.
Winter wash trees to destroy eggs.
Prevention
Keep areas around plants free from plant debris.
Remove weeds around plants.
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文章
Dummer. ゛☀
2017年09月15日
Mature plants can exhibit wilting, discoloured leaves. Younger and newly transplanted plants can show slower growth, and may eventually be killed.
Plants affected
Virtually all Brassica plants are attacked as well as some ornamentals.
About
Adults are similar in appearance and size to common house flies.
Larvae are white, legless grubs up to 1cm long, and can be found in the soil around plant roots.
Pupae are reddish brown, and are also found in the soil.
After over-wintering, adults emerge from pupal cases in late April / May to mate, and lay small white eggs in the soil at the base of plants.
Eggs will hatch in about a week and the tiny white larvae will begin feeding on the roots of susceptible plants.
After around a month of feeding, the larvae will pupate below the soil surface.
A second generation of adults will emerge in June / July, and a third later in the autumn.
Damage to older plants from larval feeding rarely results in death, although yields may be reduced.
Treatment
Organic
Regularly cultivate soil to expose larvae and pupae to predators. Chickens are particularly good for this, if you have access to them. Allow them onto the land during the winter, when they will happily consume the larvae.
Encourage insectivorous birds by hanging boxes and feeders.
Encourage predatory ground beetles by providing suitable winter shelters.
Prevention
Fleeces and netting can be used around bedding plants to prevent flies laying eggs. Alternatively, lay 15cm discs of carpet, plastic or cardboard around the base of plants.
Use sticky traps around plants to trap adults, and to monitor the first signs of pest presence.
A four year crop rotation will help stop larvae populations from building up in the soil. In simple terms, after growing brassicas, do not grow more brassicas in the same place for at least four years.
Plants affected
Virtually all Brassica plants are attacked as well as some ornamentals.
About
Adults are similar in appearance and size to common house flies.
Larvae are white, legless grubs up to 1cm long, and can be found in the soil around plant roots.
Pupae are reddish brown, and are also found in the soil.
After over-wintering, adults emerge from pupal cases in late April / May to mate, and lay small white eggs in the soil at the base of plants.
Eggs will hatch in about a week and the tiny white larvae will begin feeding on the roots of susceptible plants.
After around a month of feeding, the larvae will pupate below the soil surface.
A second generation of adults will emerge in June / July, and a third later in the autumn.
Damage to older plants from larval feeding rarely results in death, although yields may be reduced.
Treatment
Organic
Regularly cultivate soil to expose larvae and pupae to predators. Chickens are particularly good for this, if you have access to them. Allow them onto the land during the winter, when they will happily consume the larvae.
Encourage insectivorous birds by hanging boxes and feeders.
Encourage predatory ground beetles by providing suitable winter shelters.
Prevention
Fleeces and netting can be used around bedding plants to prevent flies laying eggs. Alternatively, lay 15cm discs of carpet, plastic or cardboard around the base of plants.
Use sticky traps around plants to trap adults, and to monitor the first signs of pest presence.
A four year crop rotation will help stop larvae populations from building up in the soil. In simple terms, after growing brassicas, do not grow more brassicas in the same place for at least four years.
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文章
Dummer. ゛☀
2017年09月15日
Colonies of aphids can be found in clusters on soft new growth of a wide variety of plants. Buds, tips of stems and the undersides of leaves are all good places to look. Aphids come in many different colours from common greenfly and blackfly to yellows, browns and whites. Many species are specific to one group of plants but they all need to be dealt with in a similar way.
Plants affected
From time to time, aphids may attack almost any garden plant.
About
Adult aphids are rarely more than 3mm long and are elliptical in shape.
Large colonies can cover areas on the youngest sections of stems, and the undersides of leaves and sometimes on flower-buds.
During the warmer months aphids give birth to as many as five live young a day, so large colonies can develop very quickly.
When the colonies become over-populated, they move to different locations by producing winged aphids.
During the cooler months, aphids mate and produce eggs which over-winter.
Aphids feed on plant sap and excrete plant sugars as honeydew.
Honeydew often covers the leaves of a plant and then becomes infested with black sooty moulds.
Treatment
Chemical
Lambda-cyhalothrin and deltamethrin are both contact insecticides which are effective only when sprayed directly onto the aphids. A suitable systemic insecticide is thiacloprid which is taken in through the leaves and is taken up by the feeding aphids. Naturally occurring insecticides such as pyrethrum and fatty acids can also be used.
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Encourage natural predators such as ladybirds and lacewings and insectivorous birds.
Have patience – when aphid populations peak, predatory insects will soon move in. Often this is when people lose their nerve and turn to sprays and, in doing so, kill all the natural predators too.
Don’t over-feed plants. Too much fertilizer will lead to lots of soft, sappy growth which will encourage aphid attacks.
Consider planting a sacrificial crop near to vegetables. For example, nasturtiums which attract black-fly away from brassicas.
Infestations in greenhouses or conservatories can be effectively treated with a biological control such as ladybird larvae.
Plants affected
From time to time, aphids may attack almost any garden plant.
About
Adult aphids are rarely more than 3mm long and are elliptical in shape.
Large colonies can cover areas on the youngest sections of stems, and the undersides of leaves and sometimes on flower-buds.
During the warmer months aphids give birth to as many as five live young a day, so large colonies can develop very quickly.
When the colonies become over-populated, they move to different locations by producing winged aphids.
During the cooler months, aphids mate and produce eggs which over-winter.
Aphids feed on plant sap and excrete plant sugars as honeydew.
Honeydew often covers the leaves of a plant and then becomes infested with black sooty moulds.
Treatment
Chemical
Lambda-cyhalothrin and deltamethrin are both contact insecticides which are effective only when sprayed directly onto the aphids. A suitable systemic insecticide is thiacloprid which is taken in through the leaves and is taken up by the feeding aphids. Naturally occurring insecticides such as pyrethrum and fatty acids can also be used.
Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic
Encourage natural predators such as ladybirds and lacewings and insectivorous birds.
Have patience – when aphid populations peak, predatory insects will soon move in. Often this is when people lose their nerve and turn to sprays and, in doing so, kill all the natural predators too.
Don’t over-feed plants. Too much fertilizer will lead to lots of soft, sappy growth which will encourage aphid attacks.
Consider planting a sacrificial crop near to vegetables. For example, nasturtiums which attract black-fly away from brassicas.
Infestations in greenhouses or conservatories can be effectively treated with a biological control such as ladybird larvae.
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成长记
Dunia Carrillo
2017年09月13日
Update the growth of this plant in just 2 days that it was in a dark room. Just incredibly exciting!
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文章
Dummer. ゛☀
2017年09月13日
Citrus mealybugs, first identified in the U.S. in 1879 can infest and destroy greenhouse and outdoor crops of plant hosts such as Tulips, Cannas, Begonias, Narcissus and Coleus.
Identification
Host plants may be dropping leaves, have distorted growth or areas of mold and waxy cottony secretions. Although they are tiny, less than 5 mm long (25.4 mm per inch), wingless female mealybugs with peripheral body filaments or winged males with tail filaments may be lurking and munching in plant crevices, looking as if they had been rolled in flour and ready to be tossed into a micro-sized frying pan.
Damage
The mealybugs suck out the host plants sap, injecting toxic saliva and secreting honeydew that grows mold and a cottony wax that can disfigure flowers and make them unsuitable for the market, dining room table or kitchen windowsill. Ants who feast on the tasty honeydew ferry the wingless females to neighboring plants.
Control
A first and final defense is to destroy the infested plants as mealybug infestations can be fatal to the host plant if left untreated. A second and less radical approach is to employ beneficial insects, such as Mealybug Destroyer beetles which feed voraciously on the pests and can be purchased from commercial suppliers.
Note: Like the pest insect, these beetles do not survive cold weather so they must either be released into greenhouses, outdoors in temperate climates or outdoors during warm seasons in colder climes. In addition, birds will prey on the beetles outdoors.
Also, spreading bone meal at the base of any plants or wrapping the trunk in cloth may discourage ants from visiting and spreading the tenacious pests.
Neighborhood Watch
Other botanical derivatives such as Rotenone and Pyrethrum have been effective in some applications and controls that work in one location may not work in another, so ask other local organic gardeners or the county extension service for suggestions.
Identification
Host plants may be dropping leaves, have distorted growth or areas of mold and waxy cottony secretions. Although they are tiny, less than 5 mm long (25.4 mm per inch), wingless female mealybugs with peripheral body filaments or winged males with tail filaments may be lurking and munching in plant crevices, looking as if they had been rolled in flour and ready to be tossed into a micro-sized frying pan.
Damage
The mealybugs suck out the host plants sap, injecting toxic saliva and secreting honeydew that grows mold and a cottony wax that can disfigure flowers and make them unsuitable for the market, dining room table or kitchen windowsill. Ants who feast on the tasty honeydew ferry the wingless females to neighboring plants.
Control
A first and final defense is to destroy the infested plants as mealybug infestations can be fatal to the host plant if left untreated. A second and less radical approach is to employ beneficial insects, such as Mealybug Destroyer beetles which feed voraciously on the pests and can be purchased from commercial suppliers.
Note: Like the pest insect, these beetles do not survive cold weather so they must either be released into greenhouses, outdoors in temperate climates or outdoors during warm seasons in colder climes. In addition, birds will prey on the beetles outdoors.
Also, spreading bone meal at the base of any plants or wrapping the trunk in cloth may discourage ants from visiting and spreading the tenacious pests.
Neighborhood Watch
Other botanical derivatives such as Rotenone and Pyrethrum have been effective in some applications and controls that work in one location may not work in another, so ask other local organic gardeners or the county extension service for suggestions.
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文章
Dummer. ゛☀
2017年09月13日
HESE small, soft-bodied, pear-shaped insects cluster densely on tender new growth and the undersides of leaves to suck plant juices. Plants often can withstand some aphid feeding with no adverse effect, but badly infested plants develop distorted growth and leaves may turn yellow or drop off.
Sometimes it takes close inspection to discover an aphid infestation. They blend in so well with foliage that you may not spot them at first glance, even though hundreds are present. Many species of aphids feed on home garden plants; these insects range in color from pale green, pink, or black to red or yellow. Size is typically 1/16″–1/4″. Adult aphids are generally wingless, but winged adults will appear when overcrowded. Immature aphids (nymphs) closely resemble adults.
Both adults and nymphs feed on a wide variety of plants, including most edibles and ornamentals. In small numbers aphids do little damage, but they are able to reproduce rapidly and can quickly become a more serious problem. Also, as they feed, aphids secrete a sweet fluid called honeydew that can attract ants; sooty black fungus may grow on coated leaves. Aphids are common throughout the U.S.
Prevention and control
When fertilizing your garden, avoid applying too much nitrogen, which can stimulate plants to grow too rapidly and produce a flush of exactly the kind of tender new growth that aphids love.
Attract and release beneficial insects, such as ladybugs and lacewings, which will be happy to devour a bountiful supply of aphids.
Use a spray with neem oil, which is derived from the seed of the neem tree. It controls a wide variety of common garden insect pests such as aphids as well as fungal diseases.
Use a strong spray of water from your hose to dislodge aphids from affected plants. This will reduce their numbers dramatically. Recheck the plants a few days later and repeat the treatment if needed. (Keep in mind that water sprays will also kill beneficial insects.)
Sometimes it takes close inspection to discover an aphid infestation. They blend in so well with foliage that you may not spot them at first glance, even though hundreds are present. Many species of aphids feed on home garden plants; these insects range in color from pale green, pink, or black to red or yellow. Size is typically 1/16″–1/4″. Adult aphids are generally wingless, but winged adults will appear when overcrowded. Immature aphids (nymphs) closely resemble adults.
Both adults and nymphs feed on a wide variety of plants, including most edibles and ornamentals. In small numbers aphids do little damage, but they are able to reproduce rapidly and can quickly become a more serious problem. Also, as they feed, aphids secrete a sweet fluid called honeydew that can attract ants; sooty black fungus may grow on coated leaves. Aphids are common throughout the U.S.
Prevention and control
When fertilizing your garden, avoid applying too much nitrogen, which can stimulate plants to grow too rapidly and produce a flush of exactly the kind of tender new growth that aphids love.
Attract and release beneficial insects, such as ladybugs and lacewings, which will be happy to devour a bountiful supply of aphids.
Use a spray with neem oil, which is derived from the seed of the neem tree. It controls a wide variety of common garden insect pests such as aphids as well as fungal diseases.
Use a strong spray of water from your hose to dislodge aphids from affected plants. This will reduce their numbers dramatically. Recheck the plants a few days later and repeat the treatment if needed. (Keep in mind that water sprays will also kill beneficial insects.)
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文章
Dummer. ゛☀
2017年09月13日
Water-soaked spots on blossoms or leaves are an early symptom of this fungal disease. A cottony white growth may develop on the spots. White mold attacks many types of edible plants, including beans, peas, potatoes, soybeans, carrots and cabbage. White mold gradually spreads to all above-ground plant parts. Infected tissues wilt, yellow and die. Cool, wet weather favors the development of the disease. The fungus overwinters in the soil.
Prevention and Control
Choose disease-resistant varieties when possible.
Space plants and rows widely so that plants remain dry as much as possible.
Avoid handling plants when wet.
Water early in the day so plants dry before nightfall. Use drip irrigation or soaker hoses rather than overhead watering.
Minimize the use of nitrogen fertilizers.
Uproot and destroy diseased plants as soon as you notice them.
Prevention and Control
Choose disease-resistant varieties when possible.
Space plants and rows widely so that plants remain dry as much as possible.
Avoid handling plants when wet.
Water early in the day so plants dry before nightfall. Use drip irrigation or soaker hoses rather than overhead watering.
Minimize the use of nitrogen fertilizers.
Uproot and destroy diseased plants as soon as you notice them.
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文章
Dummer. ゛☀
2017年09月13日
A powdery white growth on leaves is the first evidence of this fungal disease, which affects beans, cucumbers, squash, pumpkins, lettuce, peas and many other kinds of plants. The fungus can spread to flowers and fruit. New growth and succulent plant tissues are particularly vulnerable to infection. Infected areas eventually turn yellow and dry up; severe infection can weaken or even kill entire plants.
Unlike other fungal diseases, powdery mildew does not require wet foliage for infection to occur, although it does require high humidity. It can spread quickly in warm, dry climates. The fungus overwinters on plant debris.
Prevention and Control
Plant powdery mildew-resistant varieties, such as Super Sugar Snap pea.
Water plants as needed to prevent moisture stress.
Keep plants well spaced and weeded to optimize air flow around the leaves.
Avoid excess nitrogen fertilizer, especially late in the growing season.
Unlike other fungal diseases, powdery mildew does not require wet foliage for infection to occur, although it does require high humidity. It can spread quickly in warm, dry climates. The fungus overwinters on plant debris.
Prevention and Control
Plant powdery mildew-resistant varieties, such as Super Sugar Snap pea.
Water plants as needed to prevent moisture stress.
Keep plants well spaced and weeded to optimize air flow around the leaves.
Avoid excess nitrogen fertilizer, especially late in the growing season.
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Dummer. ゛☀
2017年09月13日
Early symptoms of late blight infection include irregular olive or gray water-soaked lesions on the leaves and stems of tomatoes and potatoes. Both crops are vulnerable to this fungal disease at every stage of their growth cycle. A mildew-like white mold may also develop on or near these lesions. The disease spreads rapidly and can kill crops within a week of infection. (Late blight fungus, Phytophthora infestans, was the cause of the potato famine in Ireland in the 1850s.)
Unlike early blight, late blight does not cause the plant’s leaves to drop off; leaves usually remain attached even after they’ve turned brown and dried up. On tomato plants, infected fruits develop large sunken areas. These may not appear until after harvest. On potato plants, infection of leaves doesn't necessarily mean that tubers will be diseased. Tubers become infected by late blight when fungal spores wash down through the soil or tubers come in contact with foliage at harvest.
To prevent this from happening, remove and destroy all potato foliage and wait a week before harvesting to allow the tuber skins to cure. Monitor potatoes in storage for dry brownish rotted areas; disease symptoms may not appear until after harvest.
Wet weather with cool nights and warm days favors the spread of late blight. In warm parts of the United States, the pathogen can overwinter in soil and plant debris. In cold-winter areas, it survives only in potato tubers left in the soil, though the fungal spores move easily and quickly on the wind, spreading northward each growing season.
Prevention and Control
As a preventive measure, use Actinovate®, an organic fungicide. Add a copper-based product, such as our ready-to-spray Copper Fungicide, when late blight is present.
Buy certified disease-free seed and transplants. Seek out late blight-resistant varieties of tomatoes and potatoes.
Keep plant foliage as dry as possible; use drip irrigation or soaker hoses rather than overhead watering. Space plants generously to ensure good air circulation.
Uproot and destroy any volunteer tomato or potato plants that sprout in your garden.
Plants that become infected with late blight can rarely be saved. As the disease advances, the number of fungal spores produced multiplies rapidly. Remove infected plants from your garden as soon as possible. Bury deeply in the soil or put them in a plastic bag for disposal.
Be thorough when harvesting potatoes. Destroy any infected tubers that you find.
Unlike early blight, late blight does not cause the plant’s leaves to drop off; leaves usually remain attached even after they’ve turned brown and dried up. On tomato plants, infected fruits develop large sunken areas. These may not appear until after harvest. On potato plants, infection of leaves doesn't necessarily mean that tubers will be diseased. Tubers become infected by late blight when fungal spores wash down through the soil or tubers come in contact with foliage at harvest.
To prevent this from happening, remove and destroy all potato foliage and wait a week before harvesting to allow the tuber skins to cure. Monitor potatoes in storage for dry brownish rotted areas; disease symptoms may not appear until after harvest.
Wet weather with cool nights and warm days favors the spread of late blight. In warm parts of the United States, the pathogen can overwinter in soil and plant debris. In cold-winter areas, it survives only in potato tubers left in the soil, though the fungal spores move easily and quickly on the wind, spreading northward each growing season.
Prevention and Control
As a preventive measure, use Actinovate®, an organic fungicide. Add a copper-based product, such as our ready-to-spray Copper Fungicide, when late blight is present.
Buy certified disease-free seed and transplants. Seek out late blight-resistant varieties of tomatoes and potatoes.
Keep plant foliage as dry as possible; use drip irrigation or soaker hoses rather than overhead watering. Space plants generously to ensure good air circulation.
Uproot and destroy any volunteer tomato or potato plants that sprout in your garden.
Plants that become infected with late blight can rarely be saved. As the disease advances, the number of fungal spores produced multiplies rapidly. Remove infected plants from your garden as soon as possible. Bury deeply in the soil or put them in a plastic bag for disposal.
Be thorough when harvesting potatoes. Destroy any infected tubers that you find.
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