文章
Dummer. ゛☀
2017年09月15日
Hemp and russet mites are part of the eriophyid family of mites. Among the 100 or so plant-specific eriophyid species, including gall, rust, and blister mites, the tomato-attacking, microscopic russet mite is among the hardest to detect. Visible, if then, only in clusters, a single mite is too tiny to be seen by the human eye without magnification of 10x and higher. Their near invisibility makes these mites a particular threat to become established in your garden before you realize it.
Unlike spider mites, these voracious plant pests leave no webbing or other secretions when present. Visible damage to the plant is the first indication of its presence a damage often mistaken for mineral and other nutritional deficits.
Seen through a lens, russet-hemp mites are tapered, translucent, wedge-shaped cylinders that take on a yellow tint, especially in groups. Unlike most varieties of mites, eriophyid, including russet mites, have only two pairs of legs.
Like spider mites and others, they are increasing their range and are now common in places not previously seen. Because of their size, they’re effectively dispersed by wind.
Crop specific, they tend to multiply in areas of intensive growing, like the tomato raising regions of Florida, and also do quite well indoors where warm, moist environments facilitate rapid reproduction. In the past decade, they have spread from growers in California north into Oregon.
Lifecycle
Females over winter just inside stems of the plants they infest or where twigs are joined to stems. Translucent eggs, nearly adult in size, are laid in spring and go through two nymph stages, both little different than the adult. The mites produce multiple, over-lapping generations through the course of a season, maturing in as little as eight days in warm, humid conditions.
Damage
Mites are sap suckers working at the cellular level. Damage typically appears first at the bottom of plants and moves upward as they feed. Lower leaves begin to yellow and curl, the leaf droops and the stem discolors. As the plant’s nourishment is sucked away, less vigorous green growth and flowering is observed. The tiny mites, in increasing numbers, spread to all parts of the plant. The mites seem particularly attracted to flower resins and will congregate in flowers and blossoms where they can effectively hide and do great damage. If left unchecked, the mites will eventually sap the entire plant.
Russet Mite Control
The best controls for both indoor and outdoor growers are preventive methods. Make sure you don’t introduce mites into your grow space by bringing in infected plants or contaminated potting soil that may carry female mites or eggs. Regular and close scrutiny of your plants, especially around the leaves nearest the soil line if outdoors, or anywhere a plant is flowering, is crucial to early detection. What might appear to be an iron or magnesium deficiency may well be an infestation of russet mites. If in doubt, treat for mites as well as adjusting nutrient solutions or amending soil. Finding and removing mites in their first generation, a period that can be short as a week under the right conditions, can short-circuit a cascade of generations once the mites begin laying eggs.
Many of the precautions and treatments used on spider mites also apply to this pest. Inspection of plants is crucial during treatment. Look to see if damage has stopped. Remove all damaged leaves, stems, and even entire plants and dispose in a way that won’t spread the tiny creatures or its eggs.
Outdoor Plants:
Russet mites are most frequently found in outdoor container plantings. This suggests that they’re introduced both in potting soils and plants brought into the garden. Use only dependable, high-quality potting medium and plants from a nursery you trust. Don’t be afraid to ask if mites have been a problem. Even if they’ve been dealt with and the plant shows no signs of damage, eggs may still exist in the soil.
Introducing beneficial nematodes just as soil temperatures begin to warm and ahead of planting can help destroy eggs that are in the soil and nymphs once they hatch. Apply a second round of vermiculite-carried nematodes if damage to lowest leaves is spotted.
Avoid over-fertilizing plants. Mites are attracted to vigorous green growth that comes of too much nitrogen.
Periodic releases of predatory mites can blunt infestations, giving you time to deal with them. (Yes, the same spray mentioned below will also kill beneficial mites.)
Because of their near invisibility, it’s difficult to apply insecticidal soaps to suspected mite infestations. Home-made sprays using garlic, hot peppers, or citrus oils will not usually take down mites but may provide some deterrent. (Because they often arrive in the wind, russet-hemp mites aren’t easily deterred.)
Neem oil will repel and kill mites. It should be applied at first signs of damage.
Pyrethrum sprays have proven effective in killing mites but require complete coverage to ensure that none of the microscopic pests are overlooked. Tailor applications to the lifecycle of the mite. Spraying once a week — once every five days in warm conditions — for three to four weeks should cover adults, emerging nymphs, and eggs.
No matter which method you’re using, close inspection of plants during treatment is crucial. Use a lens of 14X magnification or larger to see mites gathered at the center of curled leaves, at stem junctures, or in flowers. Don’t wait to see how effective one treatment is before continuing or using another. Once infestations spread up plants, it’s almost impossible to save the plant.
Don’t hesitate to discard entire plants, even if they’re not entirely affected. While you’re treating affected plants, the mites are hurriedly spreading to others.
Prevent spreading mites. Discard infested plants in plastic bags and dispose of them in sealed garbage containers.
Indoor Plants:
Do not bring uninspected plants or plants from any grower who’s had previous problems with mites into your grow space. This is especially important, whether taking clones or tomato starts from friends and professionals. Know your grower.
Keep a clean grow space. Don’t introduce unnecessary tools used outside or suspect soil or growing mediums.
Periodic releases of spider mite predators in a greenhouse can help keep pests at bay.
At the first sign of mites, reduce their breeding environment by adjusting room temperatures and moisture content as much as possible. This will slow the breeding cycle, buying you time to inspect and treat plants before the mites next generation is spawned.
Azamax will discourage mites from feeding and slow their breeding cycle, especially helpful if you’re moving towards harvest.
Neem oil and pyrethrum/ canola oil sprays, used as above, will knock down mite infestations with repeated use.
If your grow space has been infected, clean it from top to bottom. Scrub benches and other equipment with a mild bleach solution (1:10 bleach-to-water solution is said to be safe for cleaning according to the Centers For Disease Control), sterilize all hydroponic equipment, throw away any soil that can’t be sanitized, and leave nothing that was in the space during the infestation unscrubbed. The invisible eggs of this troublesome pest can survive in tiny, unseen places.
Unlike spider mites, these voracious plant pests leave no webbing or other secretions when present. Visible damage to the plant is the first indication of its presence a damage often mistaken for mineral and other nutritional deficits.
Seen through a lens, russet-hemp mites are tapered, translucent, wedge-shaped cylinders that take on a yellow tint, especially in groups. Unlike most varieties of mites, eriophyid, including russet mites, have only two pairs of legs.
Like spider mites and others, they are increasing their range and are now common in places not previously seen. Because of their size, they’re effectively dispersed by wind.
Crop specific, they tend to multiply in areas of intensive growing, like the tomato raising regions of Florida, and also do quite well indoors where warm, moist environments facilitate rapid reproduction. In the past decade, they have spread from growers in California north into Oregon.
Lifecycle
Females over winter just inside stems of the plants they infest or where twigs are joined to stems. Translucent eggs, nearly adult in size, are laid in spring and go through two nymph stages, both little different than the adult. The mites produce multiple, over-lapping generations through the course of a season, maturing in as little as eight days in warm, humid conditions.
Damage
Mites are sap suckers working at the cellular level. Damage typically appears first at the bottom of plants and moves upward as they feed. Lower leaves begin to yellow and curl, the leaf droops and the stem discolors. As the plant’s nourishment is sucked away, less vigorous green growth and flowering is observed. The tiny mites, in increasing numbers, spread to all parts of the plant. The mites seem particularly attracted to flower resins and will congregate in flowers and blossoms where they can effectively hide and do great damage. If left unchecked, the mites will eventually sap the entire plant.
Russet Mite Control
The best controls for both indoor and outdoor growers are preventive methods. Make sure you don’t introduce mites into your grow space by bringing in infected plants or contaminated potting soil that may carry female mites or eggs. Regular and close scrutiny of your plants, especially around the leaves nearest the soil line if outdoors, or anywhere a plant is flowering, is crucial to early detection. What might appear to be an iron or magnesium deficiency may well be an infestation of russet mites. If in doubt, treat for mites as well as adjusting nutrient solutions or amending soil. Finding and removing mites in their first generation, a period that can be short as a week under the right conditions, can short-circuit a cascade of generations once the mites begin laying eggs.
Many of the precautions and treatments used on spider mites also apply to this pest. Inspection of plants is crucial during treatment. Look to see if damage has stopped. Remove all damaged leaves, stems, and even entire plants and dispose in a way that won’t spread the tiny creatures or its eggs.
Outdoor Plants:
Russet mites are most frequently found in outdoor container plantings. This suggests that they’re introduced both in potting soils and plants brought into the garden. Use only dependable, high-quality potting medium and plants from a nursery you trust. Don’t be afraid to ask if mites have been a problem. Even if they’ve been dealt with and the plant shows no signs of damage, eggs may still exist in the soil.
Introducing beneficial nematodes just as soil temperatures begin to warm and ahead of planting can help destroy eggs that are in the soil and nymphs once they hatch. Apply a second round of vermiculite-carried nematodes if damage to lowest leaves is spotted.
Avoid over-fertilizing plants. Mites are attracted to vigorous green growth that comes of too much nitrogen.
Periodic releases of predatory mites can blunt infestations, giving you time to deal with them. (Yes, the same spray mentioned below will also kill beneficial mites.)
Because of their near invisibility, it’s difficult to apply insecticidal soaps to suspected mite infestations. Home-made sprays using garlic, hot peppers, or citrus oils will not usually take down mites but may provide some deterrent. (Because they often arrive in the wind, russet-hemp mites aren’t easily deterred.)
Neem oil will repel and kill mites. It should be applied at first signs of damage.
Pyrethrum sprays have proven effective in killing mites but require complete coverage to ensure that none of the microscopic pests are overlooked. Tailor applications to the lifecycle of the mite. Spraying once a week — once every five days in warm conditions — for three to four weeks should cover adults, emerging nymphs, and eggs.
No matter which method you’re using, close inspection of plants during treatment is crucial. Use a lens of 14X magnification or larger to see mites gathered at the center of curled leaves, at stem junctures, or in flowers. Don’t wait to see how effective one treatment is before continuing or using another. Once infestations spread up plants, it’s almost impossible to save the plant.
Don’t hesitate to discard entire plants, even if they’re not entirely affected. While you’re treating affected plants, the mites are hurriedly spreading to others.
Prevent spreading mites. Discard infested plants in plastic bags and dispose of them in sealed garbage containers.
Indoor Plants:
Do not bring uninspected plants or plants from any grower who’s had previous problems with mites into your grow space. This is especially important, whether taking clones or tomato starts from friends and professionals. Know your grower.
Keep a clean grow space. Don’t introduce unnecessary tools used outside or suspect soil or growing mediums.
Periodic releases of spider mite predators in a greenhouse can help keep pests at bay.
At the first sign of mites, reduce their breeding environment by adjusting room temperatures and moisture content as much as possible. This will slow the breeding cycle, buying you time to inspect and treat plants before the mites next generation is spawned.
Azamax will discourage mites from feeding and slow their breeding cycle, especially helpful if you’re moving towards harvest.
Neem oil and pyrethrum/ canola oil sprays, used as above, will knock down mite infestations with repeated use.
If your grow space has been infected, clean it from top to bottom. Scrub benches and other equipment with a mild bleach solution (1:10 bleach-to-water solution is said to be safe for cleaning according to the Centers For Disease Control), sterilize all hydroponic equipment, throw away any soil that can’t be sanitized, and leave nothing that was in the space during the infestation unscrubbed. The invisible eggs of this troublesome pest can survive in tiny, unseen places.
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0
文章
Dummer. ゛☀
2017年09月15日
There are more than 5,000 known species of rust on plants. Common rust (Phragmidium spp.) is a fungal disease that attacks roses, hollyhocks, snapdragons, daylilies, beans, tomatoes and lawns. It is most often found on mature plants where symptoms appear primarily on the surfaces of lower leaves.
Early on, look for white, slightly raised spots on the undersides of leaves and on the stems. After a short period of time, these spots become covered with reddish-orange spore masses. Later, leaf postules may turn yellow-green and eventually black. Severe infestations will deform and yellow leaves and cause leaf drop.
Rust diseases are favored by 4 to 8 hours of low light intensity, warm temperatures and moisture — humidity, dew or rain — followed by 8 to 16 hours of high light intensity, high temperatures and slow drying of leaf surfaces.
Black spores are visible on leaves and stems in fall and overwinter inside infected stems which are distinguished by dark, corky blotches at points of infection. The spores are spread by wind or by water splashing back up onto the foliage.
Treatment
Select rust-resistant plant varieties when available.
Pick off and destroy infected leaves and frequently rake under plants to remove all fallen debris.
Water in the early morning hours — avoiding overhead sprinklers — to give plants time to dry out during the day. Drip irrigation and soaker hoses can be used to help keep leaves dry.
Use a slow-release, organic fertilizer on crops and avoid excess nitrogen. Soft, leafy, new growth is most susceptible.
Apply copper sprays or sulfur powders to prevent infection of susceptible plants. For best results, apply early or at first sign of disease. Spray all plant parts thoroughly and repeat every 7-10 days up to the day of harvest.
Effectively treat fungal diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis and is approved for organic gardening. Best of all, it’s safe to use — you can treat and pick crops the same day!
Containing sulfur and pyrethrins, Bonide® Orchard Spray is a safe, one-hit concentrate for insect attacks and fungal problems. For best results, apply as a protective spray (2.5 oz/ gallon) early in the season. If disease, insects or wet weather are present, mix 5 oz in one gallon of water. Thoroughly spray all parts of the plant, especially new shoots.
Prune or stake plants and remove weeds to improve air circulation. Make sure to disinfect your pruning tools (one part bleach to 4 parts water) after each cut.
Use a thick layer of mulch or organic compost to cover the soil after you have raked and cleaned it well. Mulch will prevent the disease spores from splashing back up onto the leaves.
Burn or bag infected plants after the growing season (see Fall Garden Cleanup). Do NOT compost.
Early on, look for white, slightly raised spots on the undersides of leaves and on the stems. After a short period of time, these spots become covered with reddish-orange spore masses. Later, leaf postules may turn yellow-green and eventually black. Severe infestations will deform and yellow leaves and cause leaf drop.
Rust diseases are favored by 4 to 8 hours of low light intensity, warm temperatures and moisture — humidity, dew or rain — followed by 8 to 16 hours of high light intensity, high temperatures and slow drying of leaf surfaces.
Black spores are visible on leaves and stems in fall and overwinter inside infected stems which are distinguished by dark, corky blotches at points of infection. The spores are spread by wind or by water splashing back up onto the foliage.
Treatment
Select rust-resistant plant varieties when available.
Pick off and destroy infected leaves and frequently rake under plants to remove all fallen debris.
Water in the early morning hours — avoiding overhead sprinklers — to give plants time to dry out during the day. Drip irrigation and soaker hoses can be used to help keep leaves dry.
Use a slow-release, organic fertilizer on crops and avoid excess nitrogen. Soft, leafy, new growth is most susceptible.
Apply copper sprays or sulfur powders to prevent infection of susceptible plants. For best results, apply early or at first sign of disease. Spray all plant parts thoroughly and repeat every 7-10 days up to the day of harvest.
Effectively treat fungal diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis and is approved for organic gardening. Best of all, it’s safe to use — you can treat and pick crops the same day!
Containing sulfur and pyrethrins, Bonide® Orchard Spray is a safe, one-hit concentrate for insect attacks and fungal problems. For best results, apply as a protective spray (2.5 oz/ gallon) early in the season. If disease, insects or wet weather are present, mix 5 oz in one gallon of water. Thoroughly spray all parts of the plant, especially new shoots.
Prune or stake plants and remove weeds to improve air circulation. Make sure to disinfect your pruning tools (one part bleach to 4 parts water) after each cut.
Use a thick layer of mulch or organic compost to cover the soil after you have raked and cleaned it well. Mulch will prevent the disease spores from splashing back up onto the leaves.
Burn or bag infected plants after the growing season (see Fall Garden Cleanup). Do NOT compost.
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0
文章
Dummer. ゛☀
2017年09月15日
Common on many plants and easily recognized, powdery mildew is a fungal disease found throughout the United States. It is caused by a variety of closely related fungal species, each with a limited host range. (The fungi attacking your roses are unlikely to spread to your lilacs). Low soil moisture combined with high humidity levels at the plant surface favors this disease.
Symptoms usually appear later in the growing season on outdoor plants. Powdery mildew starts on young leaves as raised blister-like areas that cause leaves to curl, exposing the lower leaf surface. Infected leaves become covered with a white to gray powdery growth, usually on the upper surface; unopened flower buds may be white with mildew and may never open. Leaves of severely infected plants turn brown and drop. The disease prefers young, succulent growth; mature leaves are usually not affected.
Fungal spores overwinter inside leaf buds and other plant debris. Wind, water and insects transmit the spores to other nearby plants. Zucchini, beans, cucumbers, squash, pumpkins, tomatoes, roses and zinnia are especially susceptible.
Treatment
Plant resistant cultivars in sunny locations whenever possible.
Prune or stake plants to improve air circulation. Make sure to disinfect your pruning tools (one part bleach to 4 parts water) after each cut.
Remove diseased foliage from the plant and clean up fallen debris on the ground.
Use a thick layer of mulch or organic compost to cover the soil after you have raked and cleaned it well. Mulch will prevent the disease spores from splashing back up onto the leaves.
Wash foliage occasionally to disrupt the daily spore-releasing cycle. Neem oil and PM Wash, used on a 7 day schedule, will prevent fungal attack on plants grown indoors.
Water in the morning, so plants have a chance to dry during the day. Drip irrigation and soaker hoses will help keep the foliage dry.
Use a slow-release, organic fertilizer on crops and avoid excess nitrogen. Soft, leafy, new growth is most susceptible.
Destroy all plant debris after harvest (see Fall Garden Cleanup). Do NOT compost.
If disease symptoms are observed, treat plants with one of the following approved organic fungicides:
Apply sulfur or copper-based fungicides to prevent infection of susceptible plants. For best results, apply early or at first sign of disease. Spray all plant parts thoroughly and repeat at 7-10 day intervals up to the day of harvest.
Green Cure Fungicide contains a patented formula of potassium bicarbonate — commonly used in food products — that kills many plant diseases on contact and provides up to 2 weeks of residual protection. At first sign of disease, mix 1-2 Tbsp/ gallon of water and apply to all exposed surfaces of the plant. Monterey® BI-CARB is a similar product containing micro-encapsulated potassium bicarbonate as the active ingredient. Mix 4 tsps in 2 gallons of water to thoroughly cover foliage.
Effectively treat fungal diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is approved for organic gardening. Best of all, it’s safe to use — you can treat and pick crops the same day!
SNS 244 and Zero Tolerance Herbal Fungicide are made from 100% pure, food-grade ingredients that work fast to kill existing plant diseases and prevent new fungal problems from starting.
Indoor growers may want to consider using a Sulfur Burner/ Vaporizer which turns sulfur prills into a fine dust and changes the pH of leaf surfaces. Fungal spores and mold can’t get established on this plant coating. As an added benefit, studies have shown that this dust will eliminate spider mites.
Symptoms usually appear later in the growing season on outdoor plants. Powdery mildew starts on young leaves as raised blister-like areas that cause leaves to curl, exposing the lower leaf surface. Infected leaves become covered with a white to gray powdery growth, usually on the upper surface; unopened flower buds may be white with mildew and may never open. Leaves of severely infected plants turn brown and drop. The disease prefers young, succulent growth; mature leaves are usually not affected.
Fungal spores overwinter inside leaf buds and other plant debris. Wind, water and insects transmit the spores to other nearby plants. Zucchini, beans, cucumbers, squash, pumpkins, tomatoes, roses and zinnia are especially susceptible.
Treatment
Plant resistant cultivars in sunny locations whenever possible.
Prune or stake plants to improve air circulation. Make sure to disinfect your pruning tools (one part bleach to 4 parts water) after each cut.
Remove diseased foliage from the plant and clean up fallen debris on the ground.
Use a thick layer of mulch or organic compost to cover the soil after you have raked and cleaned it well. Mulch will prevent the disease spores from splashing back up onto the leaves.
Wash foliage occasionally to disrupt the daily spore-releasing cycle. Neem oil and PM Wash, used on a 7 day schedule, will prevent fungal attack on plants grown indoors.
Water in the morning, so plants have a chance to dry during the day. Drip irrigation and soaker hoses will help keep the foliage dry.
Use a slow-release, organic fertilizer on crops and avoid excess nitrogen. Soft, leafy, new growth is most susceptible.
Destroy all plant debris after harvest (see Fall Garden Cleanup). Do NOT compost.
If disease symptoms are observed, treat plants with one of the following approved organic fungicides:
Apply sulfur or copper-based fungicides to prevent infection of susceptible plants. For best results, apply early or at first sign of disease. Spray all plant parts thoroughly and repeat at 7-10 day intervals up to the day of harvest.
Green Cure Fungicide contains a patented formula of potassium bicarbonate — commonly used in food products — that kills many plant diseases on contact and provides up to 2 weeks of residual protection. At first sign of disease, mix 1-2 Tbsp/ gallon of water and apply to all exposed surfaces of the plant. Monterey® BI-CARB is a similar product containing micro-encapsulated potassium bicarbonate as the active ingredient. Mix 4 tsps in 2 gallons of water to thoroughly cover foliage.
Effectively treat fungal diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is approved for organic gardening. Best of all, it’s safe to use — you can treat and pick crops the same day!
SNS 244 and Zero Tolerance Herbal Fungicide are made from 100% pure, food-grade ingredients that work fast to kill existing plant diseases and prevent new fungal problems from starting.
Indoor growers may want to consider using a Sulfur Burner/ Vaporizer which turns sulfur prills into a fine dust and changes the pH of leaf surfaces. Fungal spores and mold can’t get established on this plant coating. As an added benefit, studies have shown that this dust will eliminate spider mites.
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0
文章
Dummer. ゛☀
2017年09月15日
Cedar apple rust (Gymnosporangium juniperi-virginianae) is a fungal disease that requires juniper plants to complete its complicated two year life-cycle. Spores overwinter as a reddish-brown gall on young twigs of various juniper species. In early spring, during wet weather, these galls swell and bright orange masses of spores are blown by the wind where they infect susceptible apple and crab-apple trees. The spores that develop on these trees will only infect junipers the following year. From year to year, the disease must pass from junipers to apples to junipers again; it cannot spread between apple trees.
On apple and crab-apple trees, look for pale yellow pinhead sized spots on the upper surface of the leaves shortly after bloom. These gradually enlarge to bright orange-yellow spots which make the disease easy to identify. Orange spots may develop on the fruit as well. Heavily infected leaves may drop prematurely.
Treatment
Choose resistant cultivars when available.
Rake up and dispose of fallen leaves and other debris from under trees.
Remove galls from infected junipers. In some cases, juniper plants should be removed entirely.
Apply preventative, disease-fighting fungicides labeled for use on apples weekly, starting with bud break, to protect trees from spores being released by the juniper host. This occurs only once per year, so additional applications after this springtime spread are not necessary.
On juniper, rust can be controlled by spraying plants with a copper solution (0.5 to 2.0 oz/ gallon of water) at least four times between late August and late October.
Safely treat most fungal and bacterial diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is registered for organic use. Best of all, SERENADE is completely non-toxic to honey bees and beneficial insects.
Containing sulfur and pyrethrins, Bonide® Orchard Spray is a safe, one-hit concentrate for insect attacks and fungal problems. For best results, apply as a protective spray (2.5 oz/ gallon) early in the season. If disease, insects or wet weather are present, mix 5 oz in one gallon of water. Thoroughly spray all parts of the plant, especially new shoots.
Contact your local Agricultural Extension office for other possible solutions in your area.
On apple and crab-apple trees, look for pale yellow pinhead sized spots on the upper surface of the leaves shortly after bloom. These gradually enlarge to bright orange-yellow spots which make the disease easy to identify. Orange spots may develop on the fruit as well. Heavily infected leaves may drop prematurely.
Treatment
Choose resistant cultivars when available.
Rake up and dispose of fallen leaves and other debris from under trees.
Remove galls from infected junipers. In some cases, juniper plants should be removed entirely.
Apply preventative, disease-fighting fungicides labeled for use on apples weekly, starting with bud break, to protect trees from spores being released by the juniper host. This occurs only once per year, so additional applications after this springtime spread are not necessary.
On juniper, rust can be controlled by spraying plants with a copper solution (0.5 to 2.0 oz/ gallon of water) at least four times between late August and late October.
Safely treat most fungal and bacterial diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is registered for organic use. Best of all, SERENADE is completely non-toxic to honey bees and beneficial insects.
Containing sulfur and pyrethrins, Bonide® Orchard Spray is a safe, one-hit concentrate for insect attacks and fungal problems. For best results, apply as a protective spray (2.5 oz/ gallon) early in the season. If disease, insects or wet weather are present, mix 5 oz in one gallon of water. Thoroughly spray all parts of the plant, especially new shoots.
Contact your local Agricultural Extension office for other possible solutions in your area.
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0
文章
Dummer. ゛☀
2017年09月14日
Generally found in the eastern part of the United States, anthracnose is caused by fungi in the genus Colletotrichum, a common group of plant pathogens that are responsible for diseases on many plant species. Infected plants develop dark, water soaked lesions on stems, leaves or fruit. The centers of these lesions often become covered with pink, gelatinous masses of spores especially during moist, warm weather. Anthracnose can reduce a beautiful harvest into rotted waste in just a few days.
The fungal disease overwinters in and on seeds, soil and garden debris. Cool wet weather promotes its development, and the optimum temperature for continued growth of the spores is between 75-85˚F. Moisture is required for development and germination of the fungus as well as for infection of the plant. It is spread by wind, rain, insects and garden tools.
Treatment
Choose resistant plant varieties when possible and use western grown seeds which have not been exposed to the disease.
If this fungal problem is common, do NOT save your own seed from plantings.
To avoid spreading the disease, keep out of gardens when plants are wet and make sure to disinfect all garden tools (one part bleach to 4 parts water) after use.
Do not compost infected leaves, fruit or stems and thoroughly clean up garden areas in the fall, after harvest, to reduce over wintering sites for the fungal spores.
Safely treat most fungal and bacterial diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is registered for organic use. Best of all, SERENADE is completely non-toxic to honey bees and beneficial insects.
Liquid copper sprays and sulfur powders should be applied weekly, starting when foliage begins to develop in the early spring and continuing throughout the growing season. Spray early in the day, and avoid applications during hot weather. Seeds may also be treated prior to planting.
Neem oil spray is an organic, multi-purpose fungicide/insecticide/miticide that kills eggs, larvae and adult stages of insects as well as prevents fungal attack on plants. Apply early, at the first sign of spring budding, every 7-14 days as a preventative measure or on a 7-day schedule until existing problems are eliminated.
The fungal disease overwinters in and on seeds, soil and garden debris. Cool wet weather promotes its development, and the optimum temperature for continued growth of the spores is between 75-85˚F. Moisture is required for development and germination of the fungus as well as for infection of the plant. It is spread by wind, rain, insects and garden tools.
Treatment
Choose resistant plant varieties when possible and use western grown seeds which have not been exposed to the disease.
If this fungal problem is common, do NOT save your own seed from plantings.
To avoid spreading the disease, keep out of gardens when plants are wet and make sure to disinfect all garden tools (one part bleach to 4 parts water) after use.
Do not compost infected leaves, fruit or stems and thoroughly clean up garden areas in the fall, after harvest, to reduce over wintering sites for the fungal spores.
Safely treat most fungal and bacterial diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is registered for organic use. Best of all, SERENADE is completely non-toxic to honey bees and beneficial insects.
Liquid copper sprays and sulfur powders should be applied weekly, starting when foliage begins to develop in the early spring and continuing throughout the growing season. Spray early in the day, and avoid applications during hot weather. Seeds may also be treated prior to planting.
Neem oil spray is an organic, multi-purpose fungicide/insecticide/miticide that kills eggs, larvae and adult stages of insects as well as prevents fungal attack on plants. Apply early, at the first sign of spring budding, every 7-14 days as a preventative measure or on a 7-day schedule until existing problems are eliminated.
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0
文章
Dummer. ゛☀
2017年09月14日
Many species of the spider mite (family: Tetranychidae), so common in North America, attack both indoor and outdoor plants. They can be especially destructive in greenhouses.
Spider mites are not true insects, but are classed as a type of arachnid, relatives of spiders, ticks and scorpions. Adults are reddish brown or pale in color, oval-shaped and very small (1/50 inch long) – about the size of the period at the end of this sentence. Immature stages resemble the adults except only smaller.
Mites live in colonies, mostly on the underside of leaves, and feed by piercing leaf tissue and sucking up the plant fluids. Feeding marks show up as light dots on the leaves. As feeding continues, the leaves turn yellow and may dry up and drop off.
Spider mites are most common in hot, dry conditions, especially where their natural enemies have been killed off by insecticide use. Some of the many species common in North America are predators of the plant-feeding mites, which make up the vast majority. They are also very prolific, which is why heavy infestations often build up unnoticed before plants begin to show damage.
Large populations are often accompanied by fine webbing. Host plants are many and include strawberries, melons, beans, tomatoes, eggplant, ornamental flowers, trees and most houseplants.
Life Cycle
Most mite species overwinter as eggs on the leaves and bark of host plants. In early spring, as temperatures warm, tiny six-legged larvae begin hatching and feed for a few days before seeking shelter where they molt into the first nymphal stage. Nymphs have eight-legs and pass through two more molts before becoming mature adults.
After mating, females continuously produce as many as 300 eggs over a couple of weeks. Hot, dry weather favors rapid development of these pests. During such conditions the time it takes to pass from egg to adult may occur in as little as 5 days. There are several overlapping generations per year.
Note: Spider mites are wind surfers. They disperse over wide areas riding their webbing on the breezes. Careful containment and disposal of infested plants is crucial.
Damage
Spider mites, almost too small to be seen, pass into our gardens without notice. No matter how few, each survives by sucking material from plant cells. Large infestations cause visible damage. Leaves first show patterns of tiny spots or stipplings. They may change color, curl and fall off. The mites activity is visible in the tight webs that are formed under leaves and along stems.
The University of California Agricultural and Natural Resources division’s Integrated Pest Management website says the following about the damage mites cause:
On annual vegetable crops — such as squash, melons and watermelons — loss of leaves can have a significant impact on yield and lead to sunburning.
On crops such as sugar peas and beans, where pods are attacked, spider mites can cause direct damage.
On ornamentals, mites are primarily an aesthetic concern, but they can kill plants if populations become very high on annual plants. Spider mites are also important pests of field-grown roses.
Control
Chemical pesticide use actually encourages the spread of spider mites by killing the beneficial insects that prey on them. Mites are also known to develop quick resistance to various pesticides. For these reasons, it’s important to control mites with effective natural and organic methods.
Prune leaves, stems and other infested parts of plants well past any webbing and discard in trash (and not in compost piles). Don’t be hesitant to pull entire plants to prevent the mites spreading to its neighbors.
Use the Bug Blaster to wash plants with a strong stream of water and reduce pest numbers.
Commercially available beneficial insects, such as ladybugs, lacewing and predatory mites are important natural enemies. For best results, make releases when pest levels are low to medium.
Nuke Em, a relatively new organic insecticide containing food-grade ingredients, works fast and kills most indoor gardening pests at the egg, larvae or adult stage. Best of all, it does this without leaving a residue on the leaves that can impact flavor.
If populations are high, use a least-toxic, short-lived pesticide (Take Down Spray, Doktor Doom Foggers) to reduce infestations, then release predatory mites to maintain control.
Insecticidal soap, neem oil or botanical insecticides can be used to spot treat heavily infested areas.
On fruit trees, horticultural oil should be applied early in the season or late in the fall to destroy overwintering eggs.
Dust on leaves, branches and fruit encourages mites. A mid-season hosing (or two!) to remove dust from trees is a worthwhile preventative.
Water stress makes both trees and garden plants more susceptible to mite infestations. Make sure your plants are properly watered.
Spider mites are not true insects, but are classed as a type of arachnid, relatives of spiders, ticks and scorpions. Adults are reddish brown or pale in color, oval-shaped and very small (1/50 inch long) – about the size of the period at the end of this sentence. Immature stages resemble the adults except only smaller.
Mites live in colonies, mostly on the underside of leaves, and feed by piercing leaf tissue and sucking up the plant fluids. Feeding marks show up as light dots on the leaves. As feeding continues, the leaves turn yellow and may dry up and drop off.
Spider mites are most common in hot, dry conditions, especially where their natural enemies have been killed off by insecticide use. Some of the many species common in North America are predators of the plant-feeding mites, which make up the vast majority. They are also very prolific, which is why heavy infestations often build up unnoticed before plants begin to show damage.
Large populations are often accompanied by fine webbing. Host plants are many and include strawberries, melons, beans, tomatoes, eggplant, ornamental flowers, trees and most houseplants.
Life Cycle
Most mite species overwinter as eggs on the leaves and bark of host plants. In early spring, as temperatures warm, tiny six-legged larvae begin hatching and feed for a few days before seeking shelter where they molt into the first nymphal stage. Nymphs have eight-legs and pass through two more molts before becoming mature adults.
After mating, females continuously produce as many as 300 eggs over a couple of weeks. Hot, dry weather favors rapid development of these pests. During such conditions the time it takes to pass from egg to adult may occur in as little as 5 days. There are several overlapping generations per year.
Note: Spider mites are wind surfers. They disperse over wide areas riding their webbing on the breezes. Careful containment and disposal of infested plants is crucial.
Damage
Spider mites, almost too small to be seen, pass into our gardens without notice. No matter how few, each survives by sucking material from plant cells. Large infestations cause visible damage. Leaves first show patterns of tiny spots or stipplings. They may change color, curl and fall off. The mites activity is visible in the tight webs that are formed under leaves and along stems.
The University of California Agricultural and Natural Resources division’s Integrated Pest Management website says the following about the damage mites cause:
On annual vegetable crops — such as squash, melons and watermelons — loss of leaves can have a significant impact on yield and lead to sunburning.
On crops such as sugar peas and beans, where pods are attacked, spider mites can cause direct damage.
On ornamentals, mites are primarily an aesthetic concern, but they can kill plants if populations become very high on annual plants. Spider mites are also important pests of field-grown roses.
Control
Chemical pesticide use actually encourages the spread of spider mites by killing the beneficial insects that prey on them. Mites are also known to develop quick resistance to various pesticides. For these reasons, it’s important to control mites with effective natural and organic methods.
Prune leaves, stems and other infested parts of plants well past any webbing and discard in trash (and not in compost piles). Don’t be hesitant to pull entire plants to prevent the mites spreading to its neighbors.
Use the Bug Blaster to wash plants with a strong stream of water and reduce pest numbers.
Commercially available beneficial insects, such as ladybugs, lacewing and predatory mites are important natural enemies. For best results, make releases when pest levels are low to medium.
Nuke Em, a relatively new organic insecticide containing food-grade ingredients, works fast and kills most indoor gardening pests at the egg, larvae or adult stage. Best of all, it does this without leaving a residue on the leaves that can impact flavor.
If populations are high, use a least-toxic, short-lived pesticide (Take Down Spray, Doktor Doom Foggers) to reduce infestations, then release predatory mites to maintain control.
Insecticidal soap, neem oil or botanical insecticides can be used to spot treat heavily infested areas.
On fruit trees, horticultural oil should be applied early in the season or late in the fall to destroy overwintering eggs.
Dust on leaves, branches and fruit encourages mites. A mid-season hosing (or two!) to remove dust from trees is a worthwhile preventative.
Water stress makes both trees and garden plants more susceptible to mite infestations. Make sure your plants are properly watered.
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文章
Dummer. ゛☀
2017年09月14日
Many species of the root maggot exist in home gardens throughout North America. Particularly destructive to early season plantings, they feed underground on succulent roots and attack a large variety of vegetable crops including radish, cabbage, carrot, turnip and onions. Heavily infested roots are often riddles with tunnels and rotted. Affected plants lack vigor, may be stunted or yellowed and often wilt during the heat of the day. In some cases, maggots may even chew through taproots, causing plants to die.
Adults (1/5 inch long) are dark gray flies that look like the common housefly, only smaller. They lay their eggs in the soil at the base of host plants and are very good at detecting newly planted seed beds. Maggots (1/3 – 1/4 inch long) are small, yellowish white, legless larvae with tapered or pointed heads and a rear end that is blunt.
Note: Tunneling and feeding by this pest creates entry points for rot diseases such as black rot.
Life Cycle
Adults emerge in the spring or early summer from overwintering pupal cocoons in the soil. They soon mate and females begin depositing 50-200 small, white eggs in plant stems right at the soil line or in cracks in the soil near plant stems. Eggs hatch in a few days and the larvae burrow down into the soil to feed on small roots, root hairs, and germinating seeds. After feeding for 1-3 weeks, maggots begin to pupate in plant roots or the surrounding soil. There are several generations per year.
Root Maggot Control
Female flies are attracted for egg laying by the moisture emitted from newly planted seed rows. Cover seedbeds with floating row cover immediately after seeds are sown to prevent problems. Be sure the cover extends at least 6 inches on each side of the seed rows.
Apply small amounts of Diatomaceous Earth around seedling stems to deter egg laying by adults.
Yellow Sticky Traps placed around vegetable crops will capture many adult flies before they can mate and lay eggs.
Heavy paper collars or other sturdy material may be placed around the base of transplants to prevent egg laying around stems.
Applying beneficial nematodes in seed furrows or as a top dressing around plants can be effective in getting rid of the larvae.
Using a pyrethrin drench is also an effective option, but should only be considered as a last resort.
Roto-till under crop debris immediately after harvest to destroy overwintering sites.
Adults (1/5 inch long) are dark gray flies that look like the common housefly, only smaller. They lay their eggs in the soil at the base of host plants and are very good at detecting newly planted seed beds. Maggots (1/3 – 1/4 inch long) are small, yellowish white, legless larvae with tapered or pointed heads and a rear end that is blunt.
Note: Tunneling and feeding by this pest creates entry points for rot diseases such as black rot.
Life Cycle
Adults emerge in the spring or early summer from overwintering pupal cocoons in the soil. They soon mate and females begin depositing 50-200 small, white eggs in plant stems right at the soil line or in cracks in the soil near plant stems. Eggs hatch in a few days and the larvae burrow down into the soil to feed on small roots, root hairs, and germinating seeds. After feeding for 1-3 weeks, maggots begin to pupate in plant roots or the surrounding soil. There are several generations per year.
Root Maggot Control
Female flies are attracted for egg laying by the moisture emitted from newly planted seed rows. Cover seedbeds with floating row cover immediately after seeds are sown to prevent problems. Be sure the cover extends at least 6 inches on each side of the seed rows.
Apply small amounts of Diatomaceous Earth around seedling stems to deter egg laying by adults.
Yellow Sticky Traps placed around vegetable crops will capture many adult flies before they can mate and lay eggs.
Heavy paper collars or other sturdy material may be placed around the base of transplants to prevent egg laying around stems.
Applying beneficial nematodes in seed furrows or as a top dressing around plants can be effective in getting rid of the larvae.
Using a pyrethrin drench is also an effective option, but should only be considered as a last resort.
Roto-till under crop debris immediately after harvest to destroy overwintering sites.
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文章
Dummer. ゛☀
2017年09月14日
Many species of leafhoppers exist in home gardens throughout North America. Both adults and nymphs feed by puncturing the undersides of leaves and sucking out plant juices. Their toxic saliva causes spotting (white specks), yellowing, leaf curling, stunting and distortion of plants. They are also responsible for transmitting the organisms causing virus diseases in plants. Common host plants include beans, lettuce, beets, potato, grapes, roses and many others.
Leafhopper adults (1/4 inch long) are slender, wedge-shaped insects that fly or disperse rapidly when disturbed. Depending on species they may be green, brown or yellow in color and often have colorful markings. Nymphs do not have wings and are generally lighter in color than adults. Both adults and nymphs run sideways and are good jumpers.
Note: There are more leafhopper species worldwide than all species of birds, mammals, reptiles and amphibians combined.
Life Cycle
Adults overwinter in crop debris or non-cultivated areas adjacent to gardens. In late spring females deposit 1-6 eggs daily within the stems and larger veins of the leaves. Hatching occurs in 6-9 days, and the young nymphs molt 5 times before they become fully grown adults. White cast skins shed by the molting nymphs can often be found attached to the underside of damaged leaves. The period from egg to adult is about three weeks. Several overlapping generations may be completed during the growing season.
Leafhopper Control
Remove garden trash and other debris shortly after harvest to reduce over-wintering sites.
Floating row covers can be used as a physical barrier to keep leafhoppers from damaging plants.
Commercially available beneficial insects, such as ladybugs, lacewing and minute pirate bugs, are all voracious predators of both the egg and young larval stage.
Apply diatomaceous earth to plants and/or spot treat with insecticidal soap to keep pest populations under control. Thorough coverage of both upper and lower infested leaves is necessary for effective control.
If pest levels become intolerable, spot treat with potent, fast-acting organic insecticides as a last resort.
Leafhopper adults (1/4 inch long) are slender, wedge-shaped insects that fly or disperse rapidly when disturbed. Depending on species they may be green, brown or yellow in color and often have colorful markings. Nymphs do not have wings and are generally lighter in color than adults. Both adults and nymphs run sideways and are good jumpers.
Note: There are more leafhopper species worldwide than all species of birds, mammals, reptiles and amphibians combined.
Life Cycle
Adults overwinter in crop debris or non-cultivated areas adjacent to gardens. In late spring females deposit 1-6 eggs daily within the stems and larger veins of the leaves. Hatching occurs in 6-9 days, and the young nymphs molt 5 times before they become fully grown adults. White cast skins shed by the molting nymphs can often be found attached to the underside of damaged leaves. The period from egg to adult is about three weeks. Several overlapping generations may be completed during the growing season.
Leafhopper Control
Remove garden trash and other debris shortly after harvest to reduce over-wintering sites.
Floating row covers can be used as a physical barrier to keep leafhoppers from damaging plants.
Commercially available beneficial insects, such as ladybugs, lacewing and minute pirate bugs, are all voracious predators of both the egg and young larval stage.
Apply diatomaceous earth to plants and/or spot treat with insecticidal soap to keep pest populations under control. Thorough coverage of both upper and lower infested leaves is necessary for effective control.
If pest levels become intolerable, spot treat with potent, fast-acting organic insecticides as a last resort.
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文章
Dummer. ゛☀
2017年09月14日
Many species of flea beetles are found throughout the United States. They are small jumping insects (similar in appearance to fleas) commonly found in home gardens early in the growing season. A voracious pest, they will damage plants by chewing numerous small holes in the leaves, which make them look as if they have been peppered by fine buckshot. When populations are high, flea beetles can quickly defoliate and kill entire plants. They feed most on hot sunny days and attack a wide variety of plants including beans, cabbage, corn, eggplant, potatoes, peppers, tomatoes, lettuce and most seedlings.
Adults are small (1/10 inch long), shiny, dark brown or black beetles with large hind legs that allow them to jump when disturbed. Some species may have white or yellow stripes on their wing cases. Larvae are small, cream-colored worms (1/8 – 1/3 inch long). They live underground and feed on the roots and tubers of young plants as well as on germinating seeds.
Note: Flea beetles transmit viral and bacterial diseases.
Life Cycle
Adults overwinter in the soil or garden debris and become active in the spring, feeding on host plants as new growth appears. Tiny white eggs are laid on or in soil cracks around the base of plants. These hatch in about one week, and the slender white larvae feed on plant roots for approximately 2-3 weeks. Pupae usually remain in the soil for 7-9 days until adults emerge and the cycle is completed. There are one to four generations per year, depending on species and climate.
Flea Beetle Control
Remove garden trash and plow or roto-till under weeds to reduce overwintering sites.
Floating row covers are extremely effective when placed on seedlings and left in place until plants are old enough to tolerate beetle damage.
Place yellow sticky traps throughout garden rows every 15 to 30 feet to capture adults.
Beneficial nematodes applied to the soil will destroy the larval stage, reducing root feeding and helping to prevent the next generation of adults from emerging.
Apply food-grade Diatomaceous Earth for long-lasting protection. Made up of tiny fossilized aquatic organisms, that look like broken glass under the microscope, DE kills by scoring an insect’s outer layer as it crawls over the fine powder. Contains NO toxic poisons!
Surround WP (kaolin clay) forms a protective barrier film, which acts as a broad spectrum crop protectant for preventing damage from insect pests.
Azatrol EC contains azadirachtin, the key insecticidal ingredient found in neem oil. This concentrated product is approved for organic use and offers multiple modes of action, making it virtually impossible for insect resistance to develop. Best of all, it’s non-toxic to honey bees and many other beneficial insects.
Least-toxic botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
Adults are small (1/10 inch long), shiny, dark brown or black beetles with large hind legs that allow them to jump when disturbed. Some species may have white or yellow stripes on their wing cases. Larvae are small, cream-colored worms (1/8 – 1/3 inch long). They live underground and feed on the roots and tubers of young plants as well as on germinating seeds.
Note: Flea beetles transmit viral and bacterial diseases.
Life Cycle
Adults overwinter in the soil or garden debris and become active in the spring, feeding on host plants as new growth appears. Tiny white eggs are laid on or in soil cracks around the base of plants. These hatch in about one week, and the slender white larvae feed on plant roots for approximately 2-3 weeks. Pupae usually remain in the soil for 7-9 days until adults emerge and the cycle is completed. There are one to four generations per year, depending on species and climate.
Flea Beetle Control
Remove garden trash and plow or roto-till under weeds to reduce overwintering sites.
Floating row covers are extremely effective when placed on seedlings and left in place until plants are old enough to tolerate beetle damage.
Place yellow sticky traps throughout garden rows every 15 to 30 feet to capture adults.
Beneficial nematodes applied to the soil will destroy the larval stage, reducing root feeding and helping to prevent the next generation of adults from emerging.
Apply food-grade Diatomaceous Earth for long-lasting protection. Made up of tiny fossilized aquatic organisms, that look like broken glass under the microscope, DE kills by scoring an insect’s outer layer as it crawls over the fine powder. Contains NO toxic poisons!
Surround WP (kaolin clay) forms a protective barrier film, which acts as a broad spectrum crop protectant for preventing damage from insect pests.
Azatrol EC contains azadirachtin, the key insecticidal ingredient found in neem oil. This concentrated product is approved for organic use and offers multiple modes of action, making it virtually impossible for insect resistance to develop. Best of all, it’s non-toxic to honey bees and many other beneficial insects.
Least-toxic botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
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文章
Dummer. ゛☀
2017年09月14日
Many species of cutworms from the night-flying moth family Noctuidae are found in home gardens across the United States. The larvae commonly feed on plant stems at or below ground, eventually cutting them down. Cutworms attack a wide variety of plants including beets, cabbage, broccoli, kale and cauliflower.
Cutworm caterpillars (larvae) are stout, soft-bodied, gray or dull brown caterpillars (1-2 inch long) that curl up when at rest or disturbed. They feed at night and burrow into the soil during the day. Adults are dark gray or brown, night-flying moths (1-1/2 inch wingspan) with ragged blotches or stripes on their wings. They do not damage plants.
Note: Pest populations vary greatly from year to year. When numerous, cutworms can destroy up to 75% of a crop.
Life Cycle
Most species pass the winter in soil or under garden waste as young larvae. In the spring, as temperatures warm, they become active and begin feeding on plants at night remaining hidden during the day. The larvae molt several times and when fully grown pupate in the soil (late spring). Within one week moths emerge and begin laying hundreds of eggs mostly on stems and leaves. One to five generations per year, depending upon the species.
Note: Overwintering larvae and the first generation in the spring are the most damaging. A few species pass the winter as pupae or hibernating moths.
Damage
Damage occurs at night when caterpillars feed by clipping off seedling stems and young plants near or just below the soil surface. Often, an entire row of newly planted garden vegetables will be cut off during the night.
Different cutworm species will climb plants doing damage to foliage, buds and shoots. Cutworms are also known to gouge potato tubers. Late season cutworms will tunnel in fruit.
Cut worms, like their close cousins armyworms, will also frequently attack turf grass. The damage they inflict on grass — cutting off blades at the crown — is usually more dispersed than damage from army worms. Cutworms favor golf courses where they cause “ballmark” pockets of dead and missing turf both on fairways and putting greens.
Cutworm Control
Losing precious transplants once to cutworms is all most people require to implement preventive measures as part of an Integrated Pest Management plan. There’s little more heart-breaking than coming out to the garden one morning to find the seedlings you started months ago indoors have been severed at the root.
Tempted to spray chemicals after losing young plants to the slow-moving eating machines? Despite the fact that it will endanger your pets, your children and the environment, pesticide use against cutworm, reports Michigan State University Extension, is “often unsuccessful.”
Preventive Measures
Before planting a new garden remove weeds and plant debris that might feed and shelter developing larvae.
Turn the soil after fall clean up then give birds and other predators a chance to pick off the expose larvae and pupae.
Mow as closely as possible to the edge of your garden to give cutworms less to feed on and less shelter near your plants.
A three-foot wide (or more) bare-soil strip between your lawn and your garden plants makes it harder for larvae to reach your plants. It also gives you more of a chance to spot them.
Wait as late as possible before setting out starts. Cutworms go on the move early in the growing season. Give them a chance to starve before you put out dinner.
Place cardboard collars (or milk containers with the bottom cut out) around transplant stems at planting time. Be sure to work the collar into the soil at least an inch or two.
Plant sunflowers along the edge of your garden. Sunflowers are a favorite target of cutworms. The plants will attract the larvae giving you a chance to pick them from the ground before they head to your corn.
Dealing with Infestations
The presence of many birds feeding in the yard may indicate cutworms in your turf.
Handpick caterpillars after dark. This is often most productive following a rain or thorough watering.
Slow the progress of worms, who don’t like navigating dry soil, by watering in the morning then cultivating your garden’s walkways lightly to a depth of an inch or so. This cultivated soil will dry quickly while trapping moisture beneath it. Do not use mulch which gives the worms shelter.
Beneficial nematodes released in moist, spring soil will attack and destroy cutworms living underground. They’re especially beneficial to apply the season after cutworms have been a problem.
At the first sign of moths, release trichogramma wasps weekly for three consecutive weeks to parasitize cutworm eggs.
Spreading a line of diatomaceous earth around the base of plants sets up a barrier to larvae. Diatomaceous earth, the fossilized, abrasive remains of prehistoric sea life, literally lets you draw a line in the dirt that’s deadly to any larvae that pass over.
Scatter bran or corn meal mixed with Monterey Bt (Bt-kurstaki) and molasses on the soil surface to attract and kill caterpillars. Eco-Bran will also kill caterpillars that feed on it.
Cutworm caterpillars (larvae) are stout, soft-bodied, gray or dull brown caterpillars (1-2 inch long) that curl up when at rest or disturbed. They feed at night and burrow into the soil during the day. Adults are dark gray or brown, night-flying moths (1-1/2 inch wingspan) with ragged blotches or stripes on their wings. They do not damage plants.
Note: Pest populations vary greatly from year to year. When numerous, cutworms can destroy up to 75% of a crop.
Life Cycle
Most species pass the winter in soil or under garden waste as young larvae. In the spring, as temperatures warm, they become active and begin feeding on plants at night remaining hidden during the day. The larvae molt several times and when fully grown pupate in the soil (late spring). Within one week moths emerge and begin laying hundreds of eggs mostly on stems and leaves. One to five generations per year, depending upon the species.
Note: Overwintering larvae and the first generation in the spring are the most damaging. A few species pass the winter as pupae or hibernating moths.
Damage
Damage occurs at night when caterpillars feed by clipping off seedling stems and young plants near or just below the soil surface. Often, an entire row of newly planted garden vegetables will be cut off during the night.
Different cutworm species will climb plants doing damage to foliage, buds and shoots. Cutworms are also known to gouge potato tubers. Late season cutworms will tunnel in fruit.
Cut worms, like their close cousins armyworms, will also frequently attack turf grass. The damage they inflict on grass — cutting off blades at the crown — is usually more dispersed than damage from army worms. Cutworms favor golf courses where they cause “ballmark” pockets of dead and missing turf both on fairways and putting greens.
Cutworm Control
Losing precious transplants once to cutworms is all most people require to implement preventive measures as part of an Integrated Pest Management plan. There’s little more heart-breaking than coming out to the garden one morning to find the seedlings you started months ago indoors have been severed at the root.
Tempted to spray chemicals after losing young plants to the slow-moving eating machines? Despite the fact that it will endanger your pets, your children and the environment, pesticide use against cutworm, reports Michigan State University Extension, is “often unsuccessful.”
Preventive Measures
Before planting a new garden remove weeds and plant debris that might feed and shelter developing larvae.
Turn the soil after fall clean up then give birds and other predators a chance to pick off the expose larvae and pupae.
Mow as closely as possible to the edge of your garden to give cutworms less to feed on and less shelter near your plants.
A three-foot wide (or more) bare-soil strip between your lawn and your garden plants makes it harder for larvae to reach your plants. It also gives you more of a chance to spot them.
Wait as late as possible before setting out starts. Cutworms go on the move early in the growing season. Give them a chance to starve before you put out dinner.
Place cardboard collars (or milk containers with the bottom cut out) around transplant stems at planting time. Be sure to work the collar into the soil at least an inch or two.
Plant sunflowers along the edge of your garden. Sunflowers are a favorite target of cutworms. The plants will attract the larvae giving you a chance to pick them from the ground before they head to your corn.
Dealing with Infestations
The presence of many birds feeding in the yard may indicate cutworms in your turf.
Handpick caterpillars after dark. This is often most productive following a rain or thorough watering.
Slow the progress of worms, who don’t like navigating dry soil, by watering in the morning then cultivating your garden’s walkways lightly to a depth of an inch or so. This cultivated soil will dry quickly while trapping moisture beneath it. Do not use mulch which gives the worms shelter.
Beneficial nematodes released in moist, spring soil will attack and destroy cutworms living underground. They’re especially beneficial to apply the season after cutworms have been a problem.
At the first sign of moths, release trichogramma wasps weekly for three consecutive weeks to parasitize cutworm eggs.
Spreading a line of diatomaceous earth around the base of plants sets up a barrier to larvae. Diatomaceous earth, the fossilized, abrasive remains of prehistoric sea life, literally lets you draw a line in the dirt that’s deadly to any larvae that pass over.
Scatter bran or corn meal mixed with Monterey Bt (Bt-kurstaki) and molasses on the soil surface to attract and kill caterpillars. Eco-Bran will also kill caterpillars that feed on it.
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文章
Dummer. ゛☀
2017年09月14日
Cucumber beetles are found across the United States from Canada to Mexico and are either striped (Acalymma vittatum) or spotted (Diabrotica undecimpunctata howardi). Both species feed primarily on the leaves, flowers and fruits of cucurbits (cucumbers, squash, pumpkins and melons). Alternate plant hosts include beans, corn, peanuts and potatoes.
Adult cucumber beetles (1/4 inch long) are yellowish-green in color with dark heads, legs and antennae. They have distinct black spots or lengthwise stripes on their wings. During the growing season, they are found feeding on seedlings, foliage, pollen and flowers causing greatly reduced yields and sometimes plant loss. The slender white larvae (up to 1/3 inch long), have brown ends and injure plants by feeding on roots and underground stems. Heavy larvae populations can reduce plant vigor and damage melon rinds making the produce unfit for consumption or market.
Note: Adult and larval stages of the cucumber beetle transmit several plant diseases, including bacterial wilt and mosaic virus in cucurbits.
Life Cycle
Adult beetles overwinter in plant debris and garden trash. Females leave their winter sites in early spring and deposit up to 800 orange-yellow eggs in the soil near the base of plants. In about 10 days hatching occurs and the larvae feed for three or more weeks before pupating. First generation adults emerge 10 days later. A complete life cycle requires 6-9 weeks. Up to four generations can be produced in a single growing season.
Control
Select resistant varieties whenever possible.
Inspect plants frequently for beetles and handpick any that are discovered.
Floating row covers are extremely effective when placed on seedlings and left in place until plants are old enough to tolerate beetle damage.
Commercially available beneficial insects, such as ladybugs, green lacewing and the spined soldier bug, will feed on pest eggs.
Beneficial nematodes work well to curtail immature stages developing in the soil.
When applied to plants, Surround WP (kaolin clay) leaves a fine powdery film that insects find unattractive for feeding and egg-laying.
Spinosad, the active ingredient in Monterey Garden Insect Spray is approved for organic use and works on a long list of insects found on vegetable crops.
If pest levels become intolerable, spot treat with a fast-acting organic insecticide. For best results, apply to the undersides of leaves and deep into the plant canopy where insects hide.
Remove garden trash and other debris shortly after harvest to reduce overwintering sites.
Adult cucumber beetles (1/4 inch long) are yellowish-green in color with dark heads, legs and antennae. They have distinct black spots or lengthwise stripes on their wings. During the growing season, they are found feeding on seedlings, foliage, pollen and flowers causing greatly reduced yields and sometimes plant loss. The slender white larvae (up to 1/3 inch long), have brown ends and injure plants by feeding on roots and underground stems. Heavy larvae populations can reduce plant vigor and damage melon rinds making the produce unfit for consumption or market.
Note: Adult and larval stages of the cucumber beetle transmit several plant diseases, including bacterial wilt and mosaic virus in cucurbits.
Life Cycle
Adult beetles overwinter in plant debris and garden trash. Females leave their winter sites in early spring and deposit up to 800 orange-yellow eggs in the soil near the base of plants. In about 10 days hatching occurs and the larvae feed for three or more weeks before pupating. First generation adults emerge 10 days later. A complete life cycle requires 6-9 weeks. Up to four generations can be produced in a single growing season.
Control
Select resistant varieties whenever possible.
Inspect plants frequently for beetles and handpick any that are discovered.
Floating row covers are extremely effective when placed on seedlings and left in place until plants are old enough to tolerate beetle damage.
Commercially available beneficial insects, such as ladybugs, green lacewing and the spined soldier bug, will feed on pest eggs.
Beneficial nematodes work well to curtail immature stages developing in the soil.
When applied to plants, Surround WP (kaolin clay) leaves a fine powdery film that insects find unattractive for feeding and egg-laying.
Spinosad, the active ingredient in Monterey Garden Insect Spray is approved for organic use and works on a long list of insects found on vegetable crops.
If pest levels become intolerable, spot treat with a fast-acting organic insecticide. For best results, apply to the undersides of leaves and deep into the plant canopy where insects hide.
Remove garden trash and other debris shortly after harvest to reduce overwintering sites.
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文章
Dummer. ゛☀
2017年09月14日
There are approximately 4,000 aphid species found throughout the world. Low to moderate numbers are usually not harmful to plants and rarely require aphid control. However, heavy infestations will cause leaves to curl, wilt or yellow and stunted plant growth. A general decline in overall plant vigor will also be noticed. Several species can transmit plant diseases, particularly viruses which they pass on during feeding.
Aphids are small (1/8 inch long), soft bodied, pear-shaped insects that may be green, yellow, brown, red or black in color depending on species and food source. Generally adults are wingless, but some can grow wings, especially if populations are high. They have two whip-like antennae at the tip of the head and a pair of tube-like structures, called cornicles, projecting backward out of their hind end.
Note: As they feed, aphids secrete large amounts of a sticky fluid known as honeydew. This sweet goo drips onto plants, attracting ants and promoting a black sooty mold growth on leaves. Cars and lawn furniture that are under infested trees will also be covered with this sticky fluid.
Life Cycle
In spring wingless female aphids hatch from overwintering eggs and soon give birth to many nymphs (males are not present). Young nymphs increase gradually in size and within a week give birth to many more nymphs. This process is repeated several times and results in huge population explosions. As the colony grows, a few of the females develop wings and fly off to other host plants to start new colonies. In late summer and early fall sexual forms (males and females) develop which mate and lay overwintering eggs. There are many overlapping generations per year.
Note: Most aphids, except for the sexual forms, do not have to mate in order to reproduce, and they produce live young, rather than eggs.
Control
Pinch or prune off heavily infested leaves or other plant parts.
Use the Bug Blaster to hose off plants with a strong stream of water and reduce pest numbers.
Commercially available beneficial insects, such as ladybugs and lacewing are important natural predators. For best results, make releases when pest levels are low to medium. If populations are high, use a least-toxic, short-lived natural pesticide to establish control, then release predatory insects to maintain control.
Apply food-grade Diatomaceous Earth for long-lasting protection. Made up of tiny fossilized aquatic organisms, that look like broken glass under the microscope, DE kills by scoring an insect’s outer layer as it crawls over the fine powder. Contains NO toxic poisons!
Safer® Soap will work fast on heavy infestations. A short-lived natural pesticide, it works by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours. Apply 2.5 oz/ gallon of water when insects are present, repeat every 7-10 day as needed.
Horticultural oils should be applied early in the season or late in the fall to destroy overwintering eggs.
Fast-acting botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
Do not over water or over fertilize – aphids like plants with high nitrogen levels and soft new growth. Use organic fertilizers which release nutrients slowly.
Tip: Ants feed on the honeydew that sucking insects produce and will protect these pests from their natural enemies. An application of Tanglefoot Pest Barrier to the stalks of roses and other woody plants will help keep ants away.
Aphids are small (1/8 inch long), soft bodied, pear-shaped insects that may be green, yellow, brown, red or black in color depending on species and food source. Generally adults are wingless, but some can grow wings, especially if populations are high. They have two whip-like antennae at the tip of the head and a pair of tube-like structures, called cornicles, projecting backward out of their hind end.
Note: As they feed, aphids secrete large amounts of a sticky fluid known as honeydew. This sweet goo drips onto plants, attracting ants and promoting a black sooty mold growth on leaves. Cars and lawn furniture that are under infested trees will also be covered with this sticky fluid.
Life Cycle
In spring wingless female aphids hatch from overwintering eggs and soon give birth to many nymphs (males are not present). Young nymphs increase gradually in size and within a week give birth to many more nymphs. This process is repeated several times and results in huge population explosions. As the colony grows, a few of the females develop wings and fly off to other host plants to start new colonies. In late summer and early fall sexual forms (males and females) develop which mate and lay overwintering eggs. There are many overlapping generations per year.
Note: Most aphids, except for the sexual forms, do not have to mate in order to reproduce, and they produce live young, rather than eggs.
Control
Pinch or prune off heavily infested leaves or other plant parts.
Use the Bug Blaster to hose off plants with a strong stream of water and reduce pest numbers.
Commercially available beneficial insects, such as ladybugs and lacewing are important natural predators. For best results, make releases when pest levels are low to medium. If populations are high, use a least-toxic, short-lived natural pesticide to establish control, then release predatory insects to maintain control.
Apply food-grade Diatomaceous Earth for long-lasting protection. Made up of tiny fossilized aquatic organisms, that look like broken glass under the microscope, DE kills by scoring an insect’s outer layer as it crawls over the fine powder. Contains NO toxic poisons!
Safer® Soap will work fast on heavy infestations. A short-lived natural pesticide, it works by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours. Apply 2.5 oz/ gallon of water when insects are present, repeat every 7-10 day as needed.
Horticultural oils should be applied early in the season or late in the fall to destroy overwintering eggs.
Fast-acting botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
Do not over water or over fertilize – aphids like plants with high nitrogen levels and soft new growth. Use organic fertilizers which release nutrients slowly.
Tip: Ants feed on the honeydew that sucking insects produce and will protect these pests from their natural enemies. An application of Tanglefoot Pest Barrier to the stalks of roses and other woody plants will help keep ants away.
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文章
Dummer. ゛☀
2017年09月14日
Spotting Spider Tree Mites in the Garden
Spider tree mites are among the most commonly found pests in gardens. Hundreds of different species are categorized as spider mites, which are members of the Tetranychidae family. These critters can damage plants by sucking on the tissues, mainly in the leaves. The mites often cluster on the undersides of the leaves.
Eight-legged arachnids, they belong to the same class as spiders and are closely related to ticks. Like spiders, they will produce webbing on the plant. Spider mites come in a wide variety of colors, including red, yellow, green and brown. Some even change colors throughout the year, while others are translucent.
Use the tips that follow to identify signs of an infestation, the common trees spider mites target and the different ways to control them.
Signs of a Spider Mite Infestation
Spider tree mites leave visible signs of damage to trees. If your leaves develop yellow, orange, brown or gray spots, an infestation may be at work. Other signs of infestation include the following:
Leaf drop
Webbing covering the plant
Visual confirmation of the presence of mites
Common Tree and Shrub Hosts
While any tree or shrub may fall prey to spider mites, some often serve as hosts. They include:
Broadleaf evergreens
Elms
Evergreens
Fruit trees
Honeylocust
Maples
Mountain ash
Oaks
Roses
Try Biological Controls First
Several different insects and arachnids are natural predators of spider mites. Encourage these helpers by limiting the use of chemicals in the garden. Natural predators include:
Big-eyed bugs (Geocoris spp.)
Gall midge (Feltiella acari Suga)
Lacewings (Chrysopa spp.)
Minute pirate bugs (Orius app)
Predatory mites (Phytoseiidae Family)
Predatory thrips (Scolothrips spp.)
Spider mite destroyer (Stethorus app. - a genus of lady beetle)
Organic Controls
Horticultural oils and insecticidal soaps are organic methods for controlling spider mites. For example, oil from the neem tree (Azadirachta indica) can be used as an organic miticide. The timing of when you apply these oils depends on the product used, so consult with someone at your local garden center, nursery or extension center to figure out the right one for your situation.
Combining a couple of tablespoons of natural soap in a quart of water provides an inexpensive and safe way to attack spider mites. Don't add extra soap, as too much may cause leaf damage. For an added punch, include garlic or cayenne.
Water as a Control
Spider mites attack plants that are suffering from drought, so proper watering is essential to help ward off these invaders. Water is also useful in controlling spider mite infestations on houseplants, where it is harder to bring in natural predators and the use of chemicals is undesirable. Use a faucet or hose to knock off mites and webbing, making sure to hit both sides of the leaves. You could also set it in a bathtub to help make this process less messy, if indoors.
Spider tree mites are among the most commonly found pests in gardens. Hundreds of different species are categorized as spider mites, which are members of the Tetranychidae family. These critters can damage plants by sucking on the tissues, mainly in the leaves. The mites often cluster on the undersides of the leaves.
Eight-legged arachnids, they belong to the same class as spiders and are closely related to ticks. Like spiders, they will produce webbing on the plant. Spider mites come in a wide variety of colors, including red, yellow, green and brown. Some even change colors throughout the year, while others are translucent.
Use the tips that follow to identify signs of an infestation, the common trees spider mites target and the different ways to control them.
Signs of a Spider Mite Infestation
Spider tree mites leave visible signs of damage to trees. If your leaves develop yellow, orange, brown or gray spots, an infestation may be at work. Other signs of infestation include the following:
Leaf drop
Webbing covering the plant
Visual confirmation of the presence of mites
Common Tree and Shrub Hosts
While any tree or shrub may fall prey to spider mites, some often serve as hosts. They include:
Broadleaf evergreens
Elms
Evergreens
Fruit trees
Honeylocust
Maples
Mountain ash
Oaks
Roses
Try Biological Controls First
Several different insects and arachnids are natural predators of spider mites. Encourage these helpers by limiting the use of chemicals in the garden. Natural predators include:
Big-eyed bugs (Geocoris spp.)
Gall midge (Feltiella acari Suga)
Lacewings (Chrysopa spp.)
Minute pirate bugs (Orius app)
Predatory mites (Phytoseiidae Family)
Predatory thrips (Scolothrips spp.)
Spider mite destroyer (Stethorus app. - a genus of lady beetle)
Organic Controls
Horticultural oils and insecticidal soaps are organic methods for controlling spider mites. For example, oil from the neem tree (Azadirachta indica) can be used as an organic miticide. The timing of when you apply these oils depends on the product used, so consult with someone at your local garden center, nursery or extension center to figure out the right one for your situation.
Combining a couple of tablespoons of natural soap in a quart of water provides an inexpensive and safe way to attack spider mites. Don't add extra soap, as too much may cause leaf damage. For an added punch, include garlic or cayenne.
Water as a Control
Spider mites attack plants that are suffering from drought, so proper watering is essential to help ward off these invaders. Water is also useful in controlling spider mite infestations on houseplants, where it is harder to bring in natural predators and the use of chemicals is undesirable. Use a faucet or hose to knock off mites and webbing, making sure to hit both sides of the leaves. You could also set it in a bathtub to help make this process less messy, if indoors.
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文章
Dummer. ゛☀
2017年09月13日
Powdery mildew is a fungal disease that results in a powdery gray or white coating on the leaves and stems of infected plants. Several different species of fungi in the order Erysiphales can cause the disease, though the symptoms are always similar. A powdery mildew infection generally starts out as a few spores on the leaves but quickly spreads. The white powdery surface is a thick coating of the fungi spores.
The fungi easily overwinters in garden debris, and thus is very hard to eradicate entirely. It can eventually cause yellowing the leaves and premature leaf drop.
As virtually all gardeners know, powdery mildew thrives in humid conditions with moderate temperatures. In any region with humid summers, powdery mildew virtually always makes its appearance. While it can affect any plants, there are certain species much more susceptible to heavy infection:
Some Plants Susceptible to Powdery Mildew:
Apples
Begonia
California poppy
Dahlia
Delphinium
Hollyhock
Hydrangea
Lilacs
Monarda
Oak
Strawberries
Phlox
Roses
Strawberries
Zinnia
Damage to Plants
In many cases, powdery mildew does little damage to plants but is merely unattractive. And some plants seem so susceptible to powdery mildew that it is virtually unavoidable--an expected cost if you choose to grow these species. Many gardeners simply resign themselves to the fact that powdery mildew will make an appearance nearly every year and don't bother to fight it aggressively.
But besides being unattractive, powdery mildew can in extreme cases result in leaf yellowing and dropping, stunted plant growth, distortion of buds, blooms, and fruit, and eventual overall weakening of the plant.
Disease Life Cycle
Spores overwinter on diseased plant parts and begin asexual production of new spores once the weather warms.
New spores are carried on the wind to other parts of the plant or to other nearby plants. Spores never stop producing more spores, so if infected leaves are not destroyed, the problem can never be eradicated and will only get worse.
Treatment and Prevention
Powdery mildew thrives in temperatures between 60° and 80°F. Dry, shady conditions are ideal, as are areas with poor air circulation. Few chemical fungicides offer much cure for powdery mildew; the best strategies are more mechanical in nature, such as simply removing and destroying diseased plants and plant parts.
Planting disease-resistant cultivars and making sure you allow for good air flow are two ways to guard against powdery mildew. Beyond this, possible control methods to keep powdery mildew in check include the following:
Plant species that are most susceptible in a location where they can receive early morning sun. This will allow condensation to dry out quickly and reduce the humid conditions that foster the fungus.
Enhance air circulation by spacing plants well apart. Better ventilation will reduce the disease. Dense plants can be thinned out to improve air flow.
Inspect plants regularly during warm, dry conditions, and remove any leaves that show signs of infection. Destroy (do not compost!) infected plant parts.
A spray made with baking soda, if applied weekly at the first signs of infection, can protect plants against further damage.
Plants that are badly infected should be ripped out and destroyed to prevent the disease from spreading further.
A commercially available organic option is Neem oil, which both treats existing powdery mildew and protects the plant against further infection.
Interestingly enough, an effective measure in preventing and treating powdery mildew is to spray the foliage of your plants daily with plain water from the hose. Powdery mildew hates water! The only caveat with this method is to be sure you do it early in the day so that the foliage completely dries before cooler evening temperatures arrive, otherwise you may invite other fungal diseases such as black spotinto your garden.
The fungi easily overwinters in garden debris, and thus is very hard to eradicate entirely. It can eventually cause yellowing the leaves and premature leaf drop.
As virtually all gardeners know, powdery mildew thrives in humid conditions with moderate temperatures. In any region with humid summers, powdery mildew virtually always makes its appearance. While it can affect any plants, there are certain species much more susceptible to heavy infection:
Some Plants Susceptible to Powdery Mildew:
Apples
Begonia
California poppy
Dahlia
Delphinium
Hollyhock
Hydrangea
Lilacs
Monarda
Oak
Strawberries
Phlox
Roses
Strawberries
Zinnia
Damage to Plants
In many cases, powdery mildew does little damage to plants but is merely unattractive. And some plants seem so susceptible to powdery mildew that it is virtually unavoidable--an expected cost if you choose to grow these species. Many gardeners simply resign themselves to the fact that powdery mildew will make an appearance nearly every year and don't bother to fight it aggressively.
But besides being unattractive, powdery mildew can in extreme cases result in leaf yellowing and dropping, stunted plant growth, distortion of buds, blooms, and fruit, and eventual overall weakening of the plant.
Disease Life Cycle
Spores overwinter on diseased plant parts and begin asexual production of new spores once the weather warms.
New spores are carried on the wind to other parts of the plant or to other nearby plants. Spores never stop producing more spores, so if infected leaves are not destroyed, the problem can never be eradicated and will only get worse.
Treatment and Prevention
Powdery mildew thrives in temperatures between 60° and 80°F. Dry, shady conditions are ideal, as are areas with poor air circulation. Few chemical fungicides offer much cure for powdery mildew; the best strategies are more mechanical in nature, such as simply removing and destroying diseased plants and plant parts.
Planting disease-resistant cultivars and making sure you allow for good air flow are two ways to guard against powdery mildew. Beyond this, possible control methods to keep powdery mildew in check include the following:
Plant species that are most susceptible in a location where they can receive early morning sun. This will allow condensation to dry out quickly and reduce the humid conditions that foster the fungus.
Enhance air circulation by spacing plants well apart. Better ventilation will reduce the disease. Dense plants can be thinned out to improve air flow.
Inspect plants regularly during warm, dry conditions, and remove any leaves that show signs of infection. Destroy (do not compost!) infected plant parts.
A spray made with baking soda, if applied weekly at the first signs of infection, can protect plants against further damage.
Plants that are badly infected should be ripped out and destroyed to prevent the disease from spreading further.
A commercially available organic option is Neem oil, which both treats existing powdery mildew and protects the plant against further infection.
Interestingly enough, an effective measure in preventing and treating powdery mildew is to spray the foliage of your plants daily with plain water from the hose. Powdery mildew hates water! The only caveat with this method is to be sure you do it early in the day so that the foliage completely dries before cooler evening temperatures arrive, otherwise you may invite other fungal diseases such as black spotinto your garden.
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