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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
Succulents are a popular gardening trend that won’t be dying anytime soon. Enthusiasts love their geometric forms and exquisite, often intricate patterns and details. No longer viewed as just a desert or house plant, succulents can grow and actually thrive in various climates, depending on the type of succulent. In regions affected by drought, they are a smart, drought-tolerant alternative to thirsty lawns and other water-guzzling plants. With very little effort, succulents can look so good. But they still require attention. Discover how to not only keep them alive, but get them to thrive.
1. Don’t Overwater Them You love your succulents so much, you want to water them every other day to make them grow plump and lush. But what you’ll get is a soft, shriveled, squishy mess. Overwatering is a bigger problem for succulents than underwatering. Roots can rot. If it’s too late, look for healthy tissue, take some cuttings, and allow the cut end to callus (seal itself) and then replant it. Get rid of the soil in which the oversaturated succulent was in. 2. Don’t Neglect Them Succulents and cacti: those are the desert-like plants that don’t need to be watered, like, ever—right? Wrong. Their watering needs are minimal, but they still need it to survive. If you live in a region that doesn’t get much rain, water succulents regularly during their periods of active growth. This would be spring through fall. Container plants can be watered about once a week. Occasionally, let the hose drench the pot until water flows out, to remove built-up salts from the soil. 3. Group Plants with Similar Water Needs In other words, don’t plant succulents next to super-fussy perennials that require rich soil and frequent watering. Ideally, you want to have a drought-tolerant, low-water area in your garden, a moderate water area, and so on. It just makes things easier for you and your plants will be happier. 4. The Right Soil Cactus and succulent-mix soil is available by the bag at nurseries and home centers. While it’s useful for container plants, especially those that will be used as houseplants, it’s not always practical or necessary for succulents planted in the garden. Learn more about the type of soil that’s in your yard, and add amendments to make it fast-draining and on the dryer side. While some succulents are so forgiving and will grow almost anywhere, even in clay, it’s best to give them optimal growing conditions for healthy roots and beautiful plants.
5. Shed Some Light Most succulents need a mix of sunlight and shade to grow healthy. One extreme or the other is not going to result in a beautiful, happy plant. Learn about your particular succulent’s light requirements, and find the best place in your yard or space in which it plant it. A hint: the color of the plant is a tip-off to its light needs. For example, shade-loving succulents are usually in hues of yellow and green. Sun lovers are more reddish and orange. 6. Protect from Frost Succulents go dormant during the winter months, when they don’t need to be watered. In fact, watering them during dormant season can make their roots more susceptible to rot, and kill them. What they really like is a cool and dry climate. If your area is experiencing lots of rain, and your succulents are in pots, move them under eaves to avoid over-saturation, or bring them inside. Frost is another matter. Pay attention to freeze warnings. Cover with a cloth or plant under a tree, which protects succulents during the winter and summer. 7. Put Them in the Ground Some people think that succulents are houseplants, and when they are grown outdoors, must be relegated to containers and pots. While they look great in a well-designed container arrangement, succulents, just like any other plant, love to be planted in garden beds where they can be fruitful and multiply. In warmer regions that don’t experience freezing temperatures during the winter, succulents will do just fine growing in the ground or raised beds. Some are so forgiving of soil conditions that they can grow almost anywhere that has at least some soil to which they can attach their roots. 8. Allow to Callus Before Transplanting Succulents are one of the easiest plants to propagate: just take a snippet, some leaves, a stem, offset, or “baby” and plop into the soil or another pot. But before you do, allow the stem to callus-over for a few days to prevent rot. This can be done by either placing cuttings or a paper towel and leaving them for up to five days, or putting them in a container or other place where you will remember to replant them. 9. Get Rid of Harmful Insects One thing is certain: your succulent or cacti is not looking good. Symptoms include: buds that won’t open, distorted growth, cotton-like attachments to roots, tiny insects on new growth, paprika-like dots on leaves, brown bumps on stems, collapsed outer leaves, holes in leaves. The culprit? Insects. Some gardeners believe that hardy succulents and cacti are resistant to insects–not so. Consult a master gardener site online or get one of the books about succulents and cacti to help you identify the symptom, insect, and solution.
10. Protect from Disease One sign of disease in succulents is an orangeish, cancerous-like growth near or on the stem. It has probably become infected by a microscopic mite. To treat: remove the infected tissue and put the succulent in a separate container until new, healthy growth appears. To prevent spreading to other plants, remember to clean your tools after using them on infected succulents.
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
Othonna is a genus of more than 100 African plants in the Sunflower family (Asteraceae). These are evergreen or deciduous geophytes, dwarf succulents or shrubs concentrated in the Western Cape Province of South Africa and also in southern Namibia. A few species occur in summer rainfall parts of southern Africa. The genus is closely allied to Senecio and can be distinguished principally by details of the involucre. The form or habit of Othonnas is very diverse. Leaf diversity is also notable in this genus. A few species possess highly succulent leaves (Othonna capensis, Othonna sedifolia) but most have bifacial leaves that are only slightly succulent. Size and shape is variable, with most species having leaves in the 0.4 to 4 inches (1 to 10 cm) long range. The bright yellow (occasionally white or purple) flowers are the most distinguishing characteristic of the genus and the flowering times differ from different species. Some flower just before beginning their summer rest, and others flower after beginning growth in the fall.
Growing Conditions and General Care Othonna plants have a variable range of habitats, some grow in a very hot, arid regions, but they avoid the intense desiccating rays of the north and west sun, growing between rocks in southern slopes. A few species, by contrary, grow in strong direct sunlight in arid situations that become very hot and dry as well as saturated for a few weeks during their growing period. All Othonnas grow in very open situations with plenty of free air circulation all around. Othonnas fleshy leaves and daisy-like flowers make them excellent in a desert or rock garden (where hardy), or indoors as houseplants or greenhouse specimens. Othonnas tend to be fairly hardy but some of them as Othonna cacalioides can be extremely difficult in cultivation if you do not give them the right conditions: space to develop radicular system, better to keep them in flat pots. In summer protect plants from direct sunlight. In growing season they like to be moist, fresh and plenty light. They don’t like temperatures below 50°F (10°C). In the warmer months Othonnas go into their dormancy period, stop watering, place them in a shaded, cooler area, away from getting direct sunlight and with good air circulation, relatively dry. In the fall, sometime around early to mid October when nights cool down, the plants may start growing on their own, but a good soaking will help them to leaf out. A typical succulent soil mix should be suitable for growing Othonnas but additional drainage material would be recommended.
Propagation Start seed in spring at 64 to 70°F (18 to 21°C). Plants can also be propagated from basal or semi-ripe cuttings in late summer using bottom heat.
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
The genus Aztekium contains three species of small globular cacti native to a small region in the Mexican Sierra Madre. Discovered in 1929 by F. Ritter, this genus was thought to be monotypic (with Aztekium ritteri) until a second species (Aztekium hintonii) was discovered by George S. Hinton in 1991. A further species, Aztekium valdesii, was discovered in 2011 by M.A. Alvarado Vázquez in the Sierra Madre Oriental mountains.
The genus name is dedicated to the Aztec people, due to the resemblance between the plant’s shape and certain Aztec sculptures. Aztekium only grows in cracks in steep cliff faces filled with gypsum or limestone gravel and silt. The plants can look quite gnarly in the wild but carefully cultivated specimens are quite beautiful. Aztekium species offset slowly but generously in cultivation.
Growing Conditions and General Care Aztekium are by far the most challenging and difficult cacti to grow. They are having extremely slow growth, probably the slowest of the entire cactus family. They usually take several years for growth to be even noticeable. Once a specimen is established on its own roots it is no trouble to keep it, and becomes an easy plant to manage. Because of the difficulty of cultivation, Aztekiums are most often grafted to hardier stock. They need good drainage and regular water in summer. Water carefully from below in summer and keep nearly totally dry in winter. If grafted the plants can take a little more water. Just remember the graft stock is also a cactus and will rot if over watered. Provide shade from midday through the afternoon. A little morning sun is OK. If successful you’ll have tiny, white or pale pink, funnel-shaped flowers atop the plants intermittently throughout the spring and summer.
Propagation They are usually propagated by seeds. The seeds are extremely fine and germinate readily, but the seed germination rate is very low (less than 5%).
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
Adenia is a genus of flowering plants in the Passion-flower family (Passifloraceae). It is distributed in the Old World tropics and subtropics. The centers of diversity are in Madagascar, eastern and western tropical Africa, and Southeast Asia. The genus name comes from “aden”, reported as the Arabic name for the plant by Peter Forsskål, the author of the genus. Adenias have some very interesting characteristics. They are excellent members of the caudiciform succulents and some species can attain a base of more than 6.6 feet (2 m) wide. Most Adenia plants are vine growers and form a large canopy of heart shaped leaves that shade the base. Most Adenias have green trunks and branches. Some species have overlaid reds, browns, or purples that add to the beauty of the caudex. Adenias typically flower in the spring before the leaves appear.
Growing Conditions and General Care Adenia plants are summer growers and can be watered and fed regularly if planted in fast draining soil. Let the soil dry between watering if you are in a humid climate. Most of your growth will be during the warm season and the plant will have the most leaves. The plant will also grow best with the leaves exposed to bright light, but the caudex shaded. During the cool months protect the plant from frost to keep it alive. The plant normally rests during this period and water should be kept to a minimum. However, you can keep the plant active, if you can keep it above 50 degrees Fahrenheit (10 degrees Celsius). Their sap is poisonous, and they should be handled with caution, particularly when pruning.
Propagation Most cuttings do not produce a caudex so it is best to propagate by seeds. Adenias are either male or female so one of each is required to produce seeds.
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
Succulents are typically well-suited to indoor living. They can even adapt to less-than-ideal conditions and tolerate a little bit of neglect. Still, no succulent can survive in subpar conditions forever. Eventually inadequate lighting, incorrect watering, disease or pests will take their toll. Once your plants start to look sickly, you need to act quickly to right the problem. Most sickly succulents come back to life with a few simple changes to their environment or care routine.
Water and Soil Moisture One of the quickest ways to kill indoor succulents is to water them incorrectly. Succulents use their thick, fleshy leaves to store water. They’ll rely on these water reserves to survive in dry conditions, but they still require regular watering to thrive. However, too much water is deadly to these plants. From spring to fall when growth is most active, water your succulent when the top inch (2.5 cm) of the soil feels dry to the touch. Pour fresh water into the pot until it begins to drain from the holes in the bottom of the pot. Allow all of the excess water to drain away completely. For most potted succulent plants, this means watering at least once per week. During the inactive growing season, or winter, water when the plant has almost dried out, or when the soil is mostly dry to the touch but not completely bone-dry. As a general rule, you’ll need to water about once a month in the winter. If your succulents appear deflated or shriveled during this season, you may need to water more often. It’s better to water too little than too much until you figure out the ideal watering schedule.
Mineral Buildup and Water Damage Your dying succulents could be suffering damage from water treatment additives. Tap water contains minerals and other additives that build up in the soil and have the potential to damage roots and cause poor growth or even death. If you use a water softener in your home, the excess salts can also damage your succulents. A telltale sign of mineral or salt buildup is a white crust on the surface of the soil or along the sides of the pot. If you can’t collect rainwater, try watering with distilled water or water that has been filtered to remove minerals. At the very least, leaving tap water out on the counter overnight before using it allows some of the treatment chemicals to dissipate into the air. If you suspect that mineral buildup or water treatment chemicals are to blame, you have two options. First, you can flush the soil of each plant with plenty of rainwater, filtered water or distilled water to rinse away excess minerals. Second, you can repot the plant, taking special care to gently knock some but not all of the old soil away from the roots.
Lighting Conditions Succulents typically do well in a variety of home lighting conditions. They do not always adapt well to abrupt changes in light. If your succulents were outside for a long period of time or in a shady garden center and they’re now in opposite conditions in your home, they could be suffering from shock. The key to saving your succulents is to gradually introduce them to the lighting conditions in your home. For example, if they were in bright, direct outdoor light, move them first to indirect outdoor light. After a few days, move them to a slightly shadier spot. After a few more days, move them indoors near a sunny window. After about a week, try moving them to their permanent home. If your succulents don’t respond to slowly introducing them to their new lighting conditions, it could be that they need more or less light to thrive. If you placed them next to a sunny window with hot, direct light, try moving them to a bright spot that doesn’t get direct light. If they’re in a shadier location, try moving them to a brighter one. If moving them to a new location entails a big change, adjust the plants gradually. You should notice improvement within a week or two.
Insects and Disease Succulents that live in optimal conditions but still appear sickly are likely suffering from disease or insect infestation. Succulents are especially susceptible to mealy bugs, spider mites, scale and fungus gnats. Mealy bugs can be treated by applying rubbing alcohol to their fuzzy white homes with a cotton ball or cotton swab. Scale, which looks like brown scales or shells, can be treated the same way. If you’re not sure what type of pest or disease you may have, apply a product that contains a miticide, fungicide and pesticide from your local garden center. These combination products contain neem oil, fish oil, soybean oil or other types of oil, which create conditions in which insects, mites and other pests can’t survive.
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
Conifer sawflies are a unique group of defoliating insects. The various species (see "Pine Sawfly – Species") are distributed throughout the area where their preferred hosts grow. The larvae are hostspecific and feed on old and current year foliage at some point in their development. Some species have one generation per year with defoliation occurring in the spring and others produce three or more generations with defoliation occurring on into fall. Fall defoliation has a greater impact on trees and it is for this reason that sawflies having multiple generations are considered more devastating.
Sawfly adults resemble large houseflies but are actually primitive broad-waisted wasps. While true flies have one pair of wings, the sawfly has two pairs of wings. The females are equipped with an ovipositor that is serrated, which enables them to saw little slits in the needles where eggs are laid, thus the name "sawflies". Defoliation by sawflies is sporadic, occurring in localized or region-wide outbreaks lasting one or more years. Growth loss the year following a severe defoliation (greater than 75%) can average over 50% and mortality increases due to secondary invasion by bark beetles and pine sawyers.
European pine sawfly is the most common sawfly in Missouri. Symptoms and Diagnosis Sawfly larvae have the curious habit of raising their heads and tails in a threatening manner when disturbed. Overwintering eggs that have been deposited in the needles can be easily located after a heavy frost turns the egg-laying scar yellow. (See "Pine Sawfly – Species" for a detailed description of larvae.) Life Cycle - European Pine Sawfly In August to September, the adult European pine sawflies emerge from their cocoons to mate and lay eggs. Female sawflies emit a sex pheromone that helps the male locate females for mating purposes. Using her saw-like ovipositor to cut through the tough outer skin of the needle, the female sawfly deposits overwintering eggs in slits she makes in the needles. Each female may lay six to eight eggs in each of 10 to 12 needles, but this will vary by sawfly species. European pine sawflies overwinter in the egg stage.
The eggs hatch in April through May and the larvae may feed until mid-June. The larvae feed in groups or colonies, often with three or four larvae feeding on a single needle. Being small and having small mouth parts, they merely rasp off the epidermal cells from the needles, which removes the protective barrier against desiccation. Thus, needles become twisted and brown as they dry out and die. Dead needles are easily detectable when contrasted against the green or surrounding "healthy" needles. As the larvae grow, they remain together and feed from the tip of a needle to the base. The larvae feed on older foliage and move from branch to branch as they strip the needles. Mature larvae drop to the ground and spin tough, brown cocoons in the duff. A few larvae may pupate on the tree. The above life cycle is for the European pine sawfly that only has one generation per year. The life cycle of those with more than one generation per year may vary slightly as some may overwinter in the ground in the pupae stage. Climate and latitude have a great bearing on the number of generations per year.
Integrated Pest Management Strategies 1. Maintain plant vigor. Dry weather and poor soil conditions encourage damage by sawflies, therefore, water during times of drought. Keep plants vigorous with a fertilizing program. 2. Natural controls. Several parasites have been introduced to control this pest. Native birds feed on the larvae. Rodents often eat the pupae in the soil. These agents are usually not adequate in urban settings.
3. Mechanical control —egg removal. If the needles containing overwintered eggs can be found before they hatch, they can be pulled off the plant and destroyed. Do not simply throw on the ground since young could still hatch from the eggs. 4. Mechanical control. Colonies of larvae can be easily removed by clipping off the infested branch. Place these branches in a plastic bag and destroy. Colonies can also be knocked off by sharply striking the infested branch. Crush the larvae or knock into a pail of soapy water. If few colonies are present, they can be controlled using these methods, but large infestations are better controlled by general spraying.
5.Insecticide. Several horticultural oils and insecticidal soaps are labeled for control of sawflies on ornamentals. These usually work well when the sawfly larvae are small, and thorough coverage of the colony can be achieved. Pesticides registered for use include acephate (Orthene), azadirachtin (Bio-Neem, Margosan-O), or carbaryl (Sevin).
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
Pine needle scale, Chionaspis pinifoliae, is a common insect pest of pines in Missouri. It is most frequently found on Mugo, Scotch (Scots), and Ponderosa pine but will also infest Austrian, red, or white pine and most spruces. Light infestations often go unnoticed and cause little damage. As the population increases, needles become covered with the white scale insects, which suck juices from the needles. A heavy infestation can cause whole branches to die, or in severe cases, kill the plants.
Symptoms and Diagnosis The scales are whitish and only 1/10 of an inch long with a yellow spot at one end. As numbers increase, the whole needle may be covered with scale. When pried off, the scales are hollow, and depending on the time of year, they may contain eggs or feeding insects. Life Cycle Reddish-colored eggs overwinter beneath the female scales. In May to June, young, called nymphs hatch and the migrate to new locations by crawling or being blown by the wind. The nymphs settle, begin feeding, and produce a waxy, scale covering. During late July and early August, mating takes place, and eggs are laid under the scale for next year's generation. (In some locations, a second generation may occur in early fall.)
Integrated Pest Management Strategies 1. Prune and maintain vigor. Mild infestations caught early can be controlled by pruning out infested branches. Water and fertilize plant to maintain plant vigor. Use of chemical pesticides will adversely affect populations of beneficial insects that help to control the pest. 2. Properly timed dormant oil spray. A very effective control is to use a dormant oil spray in late March or early April, before new growth begins. The oil coats the scales, preventing oxygen intake so the insects suffocate. Dormant oil sprays are nontoxic to humans, birds, and pets, but must be applied at the right time to be effective and prevent damage to the plant.
3. Properly timed insecticidal sprays. Pine needle scales are very resistant to pesticides when they are protected by their scales. However, they are very vulnerable when they are in the crawler state. In St. Louis, this is around the beginning of May. Examine infested plants with a magnifying glass for the crawlers. At the presence of crawlers, spray with an insecticidal soap, a summer oil spray, acephate (Orthene) or Neem oil. A fall application may also be made around the middle of August if a fall brood of crawlers is evident.
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
There are approximately 140 North American species of lace bugs. Most have a specific host preference, which aids in identification. Some of the important species of lace bugs are for the azalea - Stephanitis pyrioides, hawthorn - Corythucha cydoniae, lantana - Teleonemia scrupulosa, and hackberry - C. celtidis. Lace bugs also feed on oak, elm, basswood, fringetree, and pyracantha among others.
The different species of adults vary from 1/8 to 3/8 inch in length but all have wings and thorax beautifully sculptured with an intricate pattern of veins that resembles lace. The nymphs are dark and are pointed at both ends. Lace bugs, both immature and adults, are most often found on the underside of leaves. The London plane tree, Platanus acerifolia, is more susceptible to the lace bug than the sycamore, Plantanus occidentalis; both are hosts to the same species of lace bug.
Symptoms and Diagnosis If heavily infested, the leaves may turn yellow and fall from trees and shrubs. The lace bug feeding mechanism is one that pierces and sucks the plant juices from leaves. This leaves tiny chlorotic flecks on the upper leaf surface. The underside of the leaves will have adults and spiny, dark-colored nymphs. The underside of leaves will look dirty with dark-brown spots and stains. When disturbed, lace bugs exhibit a peculiar bouncing movement. Life Cycle Female lace bugs lay groups of eggs on the underside of leaves most often along the midrib. These eggs are partially inserted into the leaf tissue and are pale and almost completely hidden inside the leaf. Many species secrete a brownish substance that hardens over the eggs and secures them to the leaf. Dark spiny nymphs hatch from the eggs and go through 5 to 6 nymphal instars before reaching adulthood. A complete life cycle takes only 30 to 40 days; several generations may occur each year. Lace bugs are more prevalent in late summer and fall. In late summer, both adults and nymphs will be feeding at the same time. Some species overwinter as eggs in the leaf or bark crevices or similar protected areas while other species overwinter in the adult stage.
Integrated Pest Management Strategies 1. Live with the insects but maintain plant vigor. In many cases, the damage occurs late enough in the season or is minor enough not to require action. Keeping plants healthy by watering during periods of drought will limit any damage caused by the insects. 2. Select planting areas carefully. Plant susceptible species away from sidewalks and lawns as dropping leaves, twigs, and lace bug excrement can be bad enough to be considered unpleasant.
3. Spray with water. Nymphs can be dislodged by forceful sprays of water and are vulnerable to control by contact with insecticidal soaps. 4. Sanitation. Prompt removal of leaves and twigs under plants can remove overwintering pests and limit the chances of reinfestation. 5. Control. Natural enemies are usually effective in maintaining populations at a low level and bringing outbreaks under control. Chemical controls are usually only used on shade and ornamental trees. Control of the azalea lace bug on evergreen azaleas is often required as the loss of leaves on these plants can have a more serious impact on plant health.
6. Use insecticides. Pesticides registered for use include acephate (Orthene), bendiocarb (Turcam, Closure), capsaicin, carbaryl (Sevin), disulfoton (Di-syston), malathion, permethrin, pyrethrins, and horticultural oils. Spray as soon as eggs hatch on leaves in early spring. Some control is possible with a dormant spray applied just before growth in spring.
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
Two leafminers are most prevalent. The native holly leafminer, Phytomyza ilicicola, is a common pest of American holly. The holly leafminer, P. ilicis, feeds only on English hollies. The adult of both is a small black fly only about 1/8 inch long; the larva, a maggot, tunnels in the leaves causing yellowish or brown winding trails or blotches. Leaves may also become distorted and flecked with tiny brown dots. Leaves eventually yellow and drop. This should not be confused with the natural yellowing and shedding of older leaves which occurs annually in late spring or when the plant is under stress.
Symptoms and Diagnosis Early signs are small raised bumps on the leaf where the egg has been inserted in the leaf by the female. The females also make small pinpoint holes in the leaves, called feeding punctures, through which they and adult males feed on the tender juice inside the leaf. This damage may be confused with damage caused by leaf spines, which can also cause punctures in leaves. When the young maggots hatch from the eggs, their feeding results in light green serpentine tunnels that become progressively wider as the maggot grows. In later stages, the maggot may have mined an area that looks like a spot or blotch. When scraped with a knife or pin, the upper leaf tissue will peel off revealing a mined area below. The maggot or frass (insect droppings) may be evident. In later stages, the leaves yellow and drop. Examining the leaves for tunnels will confirm the presence of leaf miner.
Life Cycle Only one generation occurs each year. The larvae overwinter in the leaves on the tree or leaves which have fallen. Adults emerge in mid-May to late June and begin laying eggs in about 10 days. The females make a slit in the leaf and deposit an egg inside the leaf. The larva hatches and the young begin feeding on the leaf tissue. Integrated Pest Management Strategies 1. Pick up and destroy infested leaves. If damage is noticed after mid-May, most insecticidal sprays will not control the pest. To limit future infestations or control a minor problem, collect and dispose of the infested leaves on the ground and on the tree in fall or winter. Do not compost the leaves. For minor problems, limit the use of insecticidal sprays used on the plants or in the area, which could kill beneficial insects, such as the small beneficial wasps that parasitize leafminer maggots.
2. Keep plants healthy. A healthy plant is better able to withstand occasional defoliation caused by leaf miners. Water during dry periods and mulch to help retain moisture. 3. Crush the small eggs or tunneling miners. Inspect small plants for early signs of damage and squeeze the eggs or young maggots. 4. If necessary, use insecticidal sprays. For severe cases, spray the new young foliage with an insecticide beginning in mid-May when the adults begin to emerge and lay eggs. Usually two follow-up sprays 7-10 days apart are needed. Check pesticide labels for directions and be sure to spray both the upper and lower sides of the leaf well. Insecticides include acephate (Orthene), spinosad and imidacloprid (Merit). Imidacloprid may also be applied to the soil in early spring.
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Dummer. ゛☀
2017年09月18日
Dummer. ゛☀
The boxwood psyllid (Psylla buxi) is the most common insect pest of Buxus sempervirens but all boxwoods are susceptible. They are found most often in the temperate parts of the United States but occur wherever boxwoods are grown in this country. It causes damage by piercing and sucking sap from buds and young leaves resulting in a conspicuous cupping of the foliage. These leaves are weakened and will usually fall off after about one year. The terminal growth will be affected for about two years.
Symptoms and Diagnosis The symptoms of a psyllid infestation are cupping of the young terminal leaves as they begin growth in spring. The psyllid nymphs will be visible inside the cupped leaves although the most obvious sign is the waxy filaments and secretions they produce. Life Cycle Boxwood psyllids have one generation per year. They overwinter as eggs in small orange spindle-shaped eggs that have been laid in between bud scales. Emerging as the new growth begins in April to May and feeding on the buds and young leaves, the nymphs are light green and may have dark markings. They produce and are partly covered with waxy filamentous secretions. The sucking damage causes the leaves to cup and creates a protected area for the developing nymphs. They mature into light green, 1/16 inch long adults that look like miniature cicadas in late May to early June. The adults lay eggs in the bud scales in June and July.
Integrated Pest Management Strategies 1. If the infestation is small, do nothing. The damage caused by boxwood psyllids is only aesthetic and rarely affects the long term health of the plant. 2. Prune out and destroy the affected tips. If done before the nymphs mature to adults, this will decrease the number of eggs for next year. The damage caused by psyllids is complete by early summer and the shrub will outgrow the injury.
3. Spray horticultural oil or insecticidal soap. Apply in early May when new growth occurs. Pesticides sprayed before or after that time will not be effective as the eggs are protected by the bud scales and the nymphs are protected by the cupped leaves. 4. Chemical controls are also available, but should only be used when the infestation is severe. Several pesticides are labeled for use against boxwood psyllids. Always be careful to read the label directions fully before applying any pesticide, and follow directions completely. Systemic insecticides may be necessary during certain stages of the psyllid’s life cycle. Pesticides that are absorbed into the foliage, such as acephate, will control adults in June.
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