文章
Miss Chen
2017年11月27日
Mushrooms are the product or fruit of fungus-infested soil and can produce rather quickly taking over a lawn. The fungus feeds off decaying substances in the soil, such as old rotting mulch, dying tree stumps and animal feces. Removal of lawn mushrooms can be difficult, once the fungus has infested a large portion of the yard. Chemical products are one way to rid the yard of the mushrooms and fungus, but are more likely to work once the matter the fungus is feeding on is removed.
Fertilizer
Fertilizers containing nitrogen not only stimulate lawn growth, but can also rid the lawn of mushrooms. Nitrogen rich soil provides the perfect base for a fast growing lawn, but also increases organic waste and matter decomposition times. Nitrogen also speeds up the growth and breakdown of the mushroom systems, lessening the lifespan of the fungus.
Fungicides
Fungicides, available in both powder and liquid form, are chemical compounds used in the removal of different types of fungi. Depending on the type of fungicide used, the chemical may either slow the growth of the fungus, keeping new growth from being reproduced or kill the fungus, causing both the fruit and root system to die. Fungicides must be used with care, especially when used in gardens or on lawns where pets and children walk or play.
Lime
Lime, used by gardeners to prevent pests from eating plants and raise the soils acidity levels in gardens and lawns, can also help slow the growth of mushrooms. Lime raises the PH level of the soil. While grass and some flowering plants thrive in a higher PH level soil, mushrooms prefer lower PH levels and will not grow well or produce fruit in acidic soils. While lime will not actually kill the mushrooms, it can work to slow and eliminate the fungus when used in conjunction with other lawn chemicals.
Considerations
While chemical products can slow the growth of fungi and even, at times, eliminate it from a lawn, fungus growth is a sign of a rich soil environment and fruit may reappear if soil conditions remain fertile. Removal of animal feces and other decaying matter, such as rotting tree stumps, can help eliminate the growth of fungi. Lawns mowed on a regular basis may also help slow the spread of growing fungi fruit. Homeowners should also not use fungus infested lawn clippings in compost, as the fungus can easily spread to any area where the compost is used.
Fertilizer
Fertilizers containing nitrogen not only stimulate lawn growth, but can also rid the lawn of mushrooms. Nitrogen rich soil provides the perfect base for a fast growing lawn, but also increases organic waste and matter decomposition times. Nitrogen also speeds up the growth and breakdown of the mushroom systems, lessening the lifespan of the fungus.
Fungicides
Fungicides, available in both powder and liquid form, are chemical compounds used in the removal of different types of fungi. Depending on the type of fungicide used, the chemical may either slow the growth of the fungus, keeping new growth from being reproduced or kill the fungus, causing both the fruit and root system to die. Fungicides must be used with care, especially when used in gardens or on lawns where pets and children walk or play.
Lime
Lime, used by gardeners to prevent pests from eating plants and raise the soils acidity levels in gardens and lawns, can also help slow the growth of mushrooms. Lime raises the PH level of the soil. While grass and some flowering plants thrive in a higher PH level soil, mushrooms prefer lower PH levels and will not grow well or produce fruit in acidic soils. While lime will not actually kill the mushrooms, it can work to slow and eliminate the fungus when used in conjunction with other lawn chemicals.
Considerations
While chemical products can slow the growth of fungi and even, at times, eliminate it from a lawn, fungus growth is a sign of a rich soil environment and fruit may reappear if soil conditions remain fertile. Removal of animal feces and other decaying matter, such as rotting tree stumps, can help eliminate the growth of fungi. Lawns mowed on a regular basis may also help slow the spread of growing fungi fruit. Homeowners should also not use fungus infested lawn clippings in compost, as the fungus can easily spread to any area where the compost is used.
0
0
文章
Miss Chen
2017年10月28日
The gray mold fungus is the main cause of mold in strawberries (Fragaria x ananassa). Gray mold, Botrytis cinerea, usually affects strawberries growing in cold or damp conditions and it makes them inedible. Contact with decayed plant material also helps spread gray mold. Strawberries grow in U.S. Department of Agriculture plant hardiness zones 2 through 11, depending on the variety. Buying new, disease-free plants every year helps reduce problems with mold.
Causes of Mold
Mold overwinters in plant debris and on living plants that carry the disease, and infects strawberries when conditions are right. Ripe, red strawberries or unripe green strawberries can suffer from mold, but the fungus most quickly affects ripening fruit.
Contact with soil, dead leaves and infected fruit spreads the mold fungus. Fungus spores can also spread through people touching infected fruits and then healthy fruits, and on the wind. Gray mold develops when temperatures are between 70 and 80 degrees Fahrenheit. Wet weather, high humidity and overhead watering also encourage mold growth. Overfertilizing strawberry plants creates lush, soft growth that's vulnerable to mold attack.
Symptoms of Infection
Strawberries infected with gray mold develop minor symptoms that gradually become worse. Infections often begin under the small leaves surrounding the strawberry stalks. Light brown spots appear, which grow larger and develop gray, dusty mold that covers the whole fruit. Strawberry fruits infected with gray mold usually maintain their shape. Infected fruits don't recover. In unfavorable conditions, such as dry, warm air and good air circulation, the disease progresses slowly. The strawberry plant's eaves and stems usually look normal, though gray mold can spread up strawberry stalks.
Preventing Mold
Avoiding crowding and shady sites and use other =controls help prevent mold in strawberries. Grow strawberry plants 2 feet apart in rows 18 inches apart in open, full-sun sites. Stagger the plants so that they are diagonally opposite in their rows.
Water strawberries with drip irrigation or soaker hoses, and not with a watering can, garden hose or sprinklers. Spread a sheet of woven plastic that allows water to penetrate, or another mulch, between the plants to prevent fruits from touching the soil. Suitable mulches include clean straw, sawdust and paper. Don't fertilize strawberries in spring, but wait until after harvesting the fruits. Apply a 16-16-16 fertilizer at a rate of 1 1/2 pound for each 100 square feet, when the strawberry leaves are dry. Don't allow the fertilizer to touch the leaves.
Removing dead and diseased fruits and foliage also helps prevent gray mold from spreading. Sterilize pruning shears by wiping the blades with a cloth that was dipped in rubbing alcohol, before and after pruning strawberries.
Treating Mold
Regular spraying with a fungicide helps protect strawberries from mold. Put on long pants, a long-sleeved shirt, safety goggles and gloves before spraying strawberries with fungicides.
On a dry, still day in spring, when new growth appears on the strawberries, dilute a fungicide containing 48.9 percent N-trichtoromethylthio~cyclohexene-1,2-dicarboximide at a rate of 2 level tablespoons per 1 gallon of water. One gallon of solution treats 100 square feet of strawberry plants. Spray the plants, covering all plant surfaces, and spray them again every seven days until harvest. Manufacturers' instructions vary from product to product, so always read the product label and follow the instructions. Make sure any product you buy is safe to use on edibles.
Causes of Mold
Mold overwinters in plant debris and on living plants that carry the disease, and infects strawberries when conditions are right. Ripe, red strawberries or unripe green strawberries can suffer from mold, but the fungus most quickly affects ripening fruit.
Contact with soil, dead leaves and infected fruit spreads the mold fungus. Fungus spores can also spread through people touching infected fruits and then healthy fruits, and on the wind. Gray mold develops when temperatures are between 70 and 80 degrees Fahrenheit. Wet weather, high humidity and overhead watering also encourage mold growth. Overfertilizing strawberry plants creates lush, soft growth that's vulnerable to mold attack.
Symptoms of Infection
Strawberries infected with gray mold develop minor symptoms that gradually become worse. Infections often begin under the small leaves surrounding the strawberry stalks. Light brown spots appear, which grow larger and develop gray, dusty mold that covers the whole fruit. Strawberry fruits infected with gray mold usually maintain their shape. Infected fruits don't recover. In unfavorable conditions, such as dry, warm air and good air circulation, the disease progresses slowly. The strawberry plant's eaves and stems usually look normal, though gray mold can spread up strawberry stalks.
Preventing Mold
Avoiding crowding and shady sites and use other =controls help prevent mold in strawberries. Grow strawberry plants 2 feet apart in rows 18 inches apart in open, full-sun sites. Stagger the plants so that they are diagonally opposite in their rows.
Water strawberries with drip irrigation or soaker hoses, and not with a watering can, garden hose or sprinklers. Spread a sheet of woven plastic that allows water to penetrate, or another mulch, between the plants to prevent fruits from touching the soil. Suitable mulches include clean straw, sawdust and paper. Don't fertilize strawberries in spring, but wait until after harvesting the fruits. Apply a 16-16-16 fertilizer at a rate of 1 1/2 pound for each 100 square feet, when the strawberry leaves are dry. Don't allow the fertilizer to touch the leaves.
Removing dead and diseased fruits and foliage also helps prevent gray mold from spreading. Sterilize pruning shears by wiping the blades with a cloth that was dipped in rubbing alcohol, before and after pruning strawberries.
Treating Mold
Regular spraying with a fungicide helps protect strawberries from mold. Put on long pants, a long-sleeved shirt, safety goggles and gloves before spraying strawberries with fungicides.
On a dry, still day in spring, when new growth appears on the strawberries, dilute a fungicide containing 48.9 percent N-trichtoromethylthio~cyclohexene-1,2-dicarboximide at a rate of 2 level tablespoons per 1 gallon of water. One gallon of solution treats 100 square feet of strawberry plants. Spray the plants, covering all plant surfaces, and spray them again every seven days until harvest. Manufacturers' instructions vary from product to product, so always read the product label and follow the instructions. Make sure any product you buy is safe to use on edibles.
0
0
文章
Miss Chen
2017年10月28日
The gray mold fungus is the main cause of mold in strawberries (Fragaria x ananassa). Gray mold, Botrytis cinerea, usually affects strawberries growing in cold or damp conditions and it makes them inedible. Contact with decayed plant material also helps spread gray mold. Strawberries grow in U.S. Department of Agriculture plant hardiness zones 2 through 11, depending on the variety. Buying new, disease-free plants every year helps reduce problems with mold.
Causes of Mold
Mold overwinters in plant debris and on living plants that carry the disease, and infects strawberries when conditions are right. Ripe, red strawberries or unripe green strawberries can suffer from mold, but the fungus most quickly affects ripening fruit.
Contact with soil, dead leaves and infected fruit spreads the mold fungus. Fungus spores can also spread through people touching infected fruits and then healthy fruits, and on the wind. Gray mold develops when temperatures are between 70 and 80 degrees Fahrenheit. Wet weather, high humidity and overhead watering also encourage mold growth. Overfertilizing strawberry plants creates lush, soft growth that's vulnerable to mold attack.
Symptoms of Infection
Strawberries infected with gray mold develop minor symptoms that gradually become worse. Infections often begin under the small leaves surrounding the strawberry stalks. Light brown spots appear, which grow larger and develop gray, dusty mold that covers the whole fruit. Strawberry fruits infected with gray mold usually maintain their shape. Infected fruits don't recover. In unfavorable conditions, such as dry, warm air and good air circulation, the disease progresses slowly. The strawberry plant's eaves and stems usually look normal, though gray mold can spread up strawberry stalks.
Preventing Mold
Avoiding crowding and shady sites and use other =controls help prevent mold in strawberries. Grow strawberry plants 2 feet apart in rows 18 inches apart in open, full-sun sites. Stagger the plants so that they are diagonally opposite in their rows.
Water strawberries with drip irrigation or soaker hoses, and not with a watering can, garden hose or sprinklers. Spread a sheet of woven plastic that allows water to penetrate, or another mulch, between the plants to prevent fruits from touching the soil. Suitable mulches include clean straw, sawdust and paper. Don't fertilize strawberries in spring, but wait until after harvesting the fruits. Apply a 16-16-16 fertilizer at a rate of 1 1/2 pound for each 100 square feet, when the strawberry leaves are dry. Don't allow the fertilizer to touch the leaves.
Removing dead and diseased fruits and foliage also helps prevent gray mold from spreading. Sterilize pruning shears by wiping the blades with a cloth that was dipped in rubbing alcohol, before and after pruning strawberries.
Treating Mold
Regular spraying with a fungicide helps protect strawberries from mold. Put on long pants, a long-sleeved shirt, safety goggles and gloves before spraying strawberries with fungicides.
On a dry, still day in spring, when new growth appears on the strawberries, dilute a fungicide containing 48.9 percent N-trichtoromethylthio~cyclohexene-1,2-dicarboximide at a rate of 2 level tablespoons per 1 gallon of water. One gallon of solution treats 100 square feet of strawberry plants. Spray the plants, covering all plant surfaces, and spray them again every seven days until harvest. Manufacturers' instructions vary from product to product, so always read the product label and follow the instructions. Make sure any product you buy is safe to use on edibles.
Causes of Mold
Mold overwinters in plant debris and on living plants that carry the disease, and infects strawberries when conditions are right. Ripe, red strawberries or unripe green strawberries can suffer from mold, but the fungus most quickly affects ripening fruit.
Contact with soil, dead leaves and infected fruit spreads the mold fungus. Fungus spores can also spread through people touching infected fruits and then healthy fruits, and on the wind. Gray mold develops when temperatures are between 70 and 80 degrees Fahrenheit. Wet weather, high humidity and overhead watering also encourage mold growth. Overfertilizing strawberry plants creates lush, soft growth that's vulnerable to mold attack.
Symptoms of Infection
Strawberries infected with gray mold develop minor symptoms that gradually become worse. Infections often begin under the small leaves surrounding the strawberry stalks. Light brown spots appear, which grow larger and develop gray, dusty mold that covers the whole fruit. Strawberry fruits infected with gray mold usually maintain their shape. Infected fruits don't recover. In unfavorable conditions, such as dry, warm air and good air circulation, the disease progresses slowly. The strawberry plant's eaves and stems usually look normal, though gray mold can spread up strawberry stalks.
Preventing Mold
Avoiding crowding and shady sites and use other =controls help prevent mold in strawberries. Grow strawberry plants 2 feet apart in rows 18 inches apart in open, full-sun sites. Stagger the plants so that they are diagonally opposite in their rows.
Water strawberries with drip irrigation or soaker hoses, and not with a watering can, garden hose or sprinklers. Spread a sheet of woven plastic that allows water to penetrate, or another mulch, between the plants to prevent fruits from touching the soil. Suitable mulches include clean straw, sawdust and paper. Don't fertilize strawberries in spring, but wait until after harvesting the fruits. Apply a 16-16-16 fertilizer at a rate of 1 1/2 pound for each 100 square feet, when the strawberry leaves are dry. Don't allow the fertilizer to touch the leaves.
Removing dead and diseased fruits and foliage also helps prevent gray mold from spreading. Sterilize pruning shears by wiping the blades with a cloth that was dipped in rubbing alcohol, before and after pruning strawberries.
Treating Mold
Regular spraying with a fungicide helps protect strawberries from mold. Put on long pants, a long-sleeved shirt, safety goggles and gloves before spraying strawberries with fungicides.
On a dry, still day in spring, when new growth appears on the strawberries, dilute a fungicide containing 48.9 percent N-trichtoromethylthio~cyclohexene-1,2-dicarboximide at a rate of 2 level tablespoons per 1 gallon of water. One gallon of solution treats 100 square feet of strawberry plants. Spray the plants, covering all plant surfaces, and spray them again every seven days until harvest. Manufacturers' instructions vary from product to product, so always read the product label and follow the instructions. Make sure any product you buy is safe to use on edibles.
0
0
文章
Miss Chen
2017年10月27日
The best fungicide for tomatoes, or any other kind of plant, is prevention. Fungicides can protect a plant if they are used before any kind of fungal infection begins. Once a fungus attacks a plant, eliminating it isn't easy. You can control its spread by continuing to spray uninfected parts of the plant, but there is little chance of stopping a fungus once it starts. Proper planting and care practices are your best weapons against tomato fungus.
Prevention
Plant tomatoes when the soil has warmed to 55 degrees Fahrenheit and the night air temperatures are in the 50s. Give the plants plenty of air circulation for when they reach their mature size; don't crowd them. Plant them in full sun in rich soil, and water only at the base of the plants, not from above with a hose or sprinkler. Wet foliage encourages fungal disease. Don't overfertilize tomatoes. A handful of tomato fertilizer and a handful of lime added to the hole when planting is all they need for the season. Plant tomatoes in a different spot every three years to prevent diseases from building up in the soil.
Septoria Blight
After the first fruits set on the plant, the lower leaves of the plant can become infected with white or gray spots with a black or brown margin. Pick off infected leaves, and discard them in the garbage. Spray the plant with an organic fungicide containing copper or a synthetic fungicide labeled for use on vegetables or one containing Chlorothalonil. Septoria spreads quickly in wet weather, so be sure the plants are well spaced, and avoid working among them when they're wet. Clean up all refuse in the fall, so the fungus doesn't overwinter in the debris.
Early Blight
Dark brown or black spots can appear on the lower leaves of the plant after the plant has set plenty of fruit. Rings appear inside the spot, making it resemble a bull's eye. The fungus attacks the stems and fruit, too, producing black, sunken spots. Leaves yellow and drop off. Pick off infected leaves and fruit, and cut off affected stems, dipping your pruners in a one-part-bleach, nine-parts-water solution between each cut. At the first sign of trouble, begin spraying the plants with an organic fungicide containing copper or a synthetic fungicide containing Clorothalonil or Mancozeb.
Late Blight
Late blight appears toward the end of the growing season when night temperatures begin to cool. Black, wet-looking spots start at the leaf edge and spread inward. Wet weather aids the spread of the fungus, and it affects the fruit, as well, with rough, dark brown patches. Remove infected plant parts, and spray with an organic fungicide containing copper or a synthetic fungicide containing Chlorothalonil or Mancozeb.
Prevention
Plant tomatoes when the soil has warmed to 55 degrees Fahrenheit and the night air temperatures are in the 50s. Give the plants plenty of air circulation for when they reach their mature size; don't crowd them. Plant them in full sun in rich soil, and water only at the base of the plants, not from above with a hose or sprinkler. Wet foliage encourages fungal disease. Don't overfertilize tomatoes. A handful of tomato fertilizer and a handful of lime added to the hole when planting is all they need for the season. Plant tomatoes in a different spot every three years to prevent diseases from building up in the soil.
Septoria Blight
After the first fruits set on the plant, the lower leaves of the plant can become infected with white or gray spots with a black or brown margin. Pick off infected leaves, and discard them in the garbage. Spray the plant with an organic fungicide containing copper or a synthetic fungicide labeled for use on vegetables or one containing Chlorothalonil. Septoria spreads quickly in wet weather, so be sure the plants are well spaced, and avoid working among them when they're wet. Clean up all refuse in the fall, so the fungus doesn't overwinter in the debris.
Early Blight
Dark brown or black spots can appear on the lower leaves of the plant after the plant has set plenty of fruit. Rings appear inside the spot, making it resemble a bull's eye. The fungus attacks the stems and fruit, too, producing black, sunken spots. Leaves yellow and drop off. Pick off infected leaves and fruit, and cut off affected stems, dipping your pruners in a one-part-bleach, nine-parts-water solution between each cut. At the first sign of trouble, begin spraying the plants with an organic fungicide containing copper or a synthetic fungicide containing Clorothalonil or Mancozeb.
Late Blight
Late blight appears toward the end of the growing season when night temperatures begin to cool. Black, wet-looking spots start at the leaf edge and spread inward. Wet weather aids the spread of the fungus, and it affects the fruit, as well, with rough, dark brown patches. Remove infected plant parts, and spray with an organic fungicide containing copper or a synthetic fungicide containing Chlorothalonil or Mancozeb.
0
0
文章
Dummer. ゛☀
2017年09月19日
Septoria leaf spot is caused by a fungus, Septoria lycopersici. It is one of the most destructive diseases of tomato foliage and is particularly severe in areas where wet, humid weather persists for extended periods.
Symptoms and Diagnosis
Septoria leaf spot usually appears on the lower leaves after the first fruit sets. Spots are circular, about 1/16 to 1/4 inch in diameter with dark brown margins and tan to gray centers with small black fruiting structures. Characteristically, there are many spots per leaf. This disease spreads upwards from oldest to youngest growth. If leaf lesions are numerous, the leaves turn slightly yellow, then brown, and then wither. Fruit infection is rare.
Life Cycle
The fungus overwinters on infected tomato debris or on weeds in the nightshade family, the same family to which tomatoes belong. The fungus can also survive on equipment such as plant stakes and cages. Long periods of high relative humidity, temperatures of 60–80 degrees F, and leaf wetness are ideal conditions for development and spread of the pathogen.
Integrated Pest Management Strategies
1. Remove diseased leaves. If caught early, the lower infected leaves can be removed and burned or destroyed. However, removing leaves above where fruit has formed will weaken the plant and expose fruit to sunscald. At the end of the season, collect all foliage from infected plants and dispose of or bury. Do not compost diseased plants.
2. Improve air circulation around the plants. If the plants can still be handled without breaking them, stake or cage the plants to raise them off the ground and promote faster drying of the foliage.
3. Mulch around the base of the plants. Mulching will reduce splashing soil, which may contain fungal spores associated with debris. Apply mulch after the soil has warmed.
4. Do not use overhead watering. Overhead watering facilitates infection and spreads the disease. Use a soaker hose at the base of the plant to keep the foliage dry. Water early in the day.
5. Control weeds. Nightshade and horsenettle are frequently hosts of Septoria leaf spot and should be eradicated around the garden site.
6. Use crop rotation. Next year do not plant tomatoes back in the same location where diseased tomatoes grew. Wait 1–2 years before replanting tomatoes in these areas.
7. Use fungicidal sprays. If the above measures do not control the disease, you may want to use fungicidal sprays. Fungicides will not cure infected leaves, but they will protect new leaves from becoming infected. Apply at 7 to 10 day intervals throughout the season. Apply chlorothalonil, maneb, macozeb, or a copper-based fungicide, such as Bordeaux mixture, copper hydroxide, copper sulfate, or copper oxychloride sulfate. Follow harvest restrictions listed on the pesticide label.
Symptoms and Diagnosis
Septoria leaf spot usually appears on the lower leaves after the first fruit sets. Spots are circular, about 1/16 to 1/4 inch in diameter with dark brown margins and tan to gray centers with small black fruiting structures. Characteristically, there are many spots per leaf. This disease spreads upwards from oldest to youngest growth. If leaf lesions are numerous, the leaves turn slightly yellow, then brown, and then wither. Fruit infection is rare.
Life Cycle
The fungus overwinters on infected tomato debris or on weeds in the nightshade family, the same family to which tomatoes belong. The fungus can also survive on equipment such as plant stakes and cages. Long periods of high relative humidity, temperatures of 60–80 degrees F, and leaf wetness are ideal conditions for development and spread of the pathogen.
Integrated Pest Management Strategies
1. Remove diseased leaves. If caught early, the lower infected leaves can be removed and burned or destroyed. However, removing leaves above where fruit has formed will weaken the plant and expose fruit to sunscald. At the end of the season, collect all foliage from infected plants and dispose of or bury. Do not compost diseased plants.
2. Improve air circulation around the plants. If the plants can still be handled without breaking them, stake or cage the plants to raise them off the ground and promote faster drying of the foliage.
3. Mulch around the base of the plants. Mulching will reduce splashing soil, which may contain fungal spores associated with debris. Apply mulch after the soil has warmed.
4. Do not use overhead watering. Overhead watering facilitates infection and spreads the disease. Use a soaker hose at the base of the plant to keep the foliage dry. Water early in the day.
5. Control weeds. Nightshade and horsenettle are frequently hosts of Septoria leaf spot and should be eradicated around the garden site.
6. Use crop rotation. Next year do not plant tomatoes back in the same location where diseased tomatoes grew. Wait 1–2 years before replanting tomatoes in these areas.
7. Use fungicidal sprays. If the above measures do not control the disease, you may want to use fungicidal sprays. Fungicides will not cure infected leaves, but they will protect new leaves from becoming infected. Apply at 7 to 10 day intervals throughout the season. Apply chlorothalonil, maneb, macozeb, or a copper-based fungicide, such as Bordeaux mixture, copper hydroxide, copper sulfate, or copper oxychloride sulfate. Follow harvest restrictions listed on the pesticide label.
0
0
文章
Dummer. ゛☀
2017年09月19日
A strain of the fungus, Phytophthora infestans, causes late blight in tomatoes. As the common name implies, Phytophthora is prevalent on tomato hosts in late summer, after the plants have bloomed. Late blight is more common in north central and northeastern states, but is observed in the Midwest when the humidity is high and temperatures are around 68 degrees F late in the growing season. Watch for the disease when cool, moist nights are followed by warm, humid days.
Symptoms and Diagnosis
One of the first symptoms of late blight is watersoaked patches on older leaves. Late blight attacks the older leaves first, then spreads to the fruit. Green-black watery patches develop on the upper surfaces of older leaves. These patches will enlarge quickly, and in moist weather, a downy growth may develop on the underside of the leaf. On the fruit, you will see rough, firm, dark-colored spots.
Life Cycle
The fungus overwinters on tomato and potato plant debris, including potato tubers. The fungus can produce spores over a broad range of temperatures although spores are most infective at temperatures of 68 degrees F with high humidity. The spores are transmitted by water or are wind blown and may be introduced from diseased plants in nearby gardens. The fungus invades the plant through leaf stomata. Infection rarely occurs when temperatures are higher than 80 degrees F and humidity is less than 90%.
Integrated Pest Management Strategies
1. Plant resistant varieties. Several tomato varieties are designated as resistant to late blight.
2. Avoid overhead watering. Avoid working around plants when they are wet. Both of these practices can spread the fungal spores from plant to plant.
3. Clean up all garden debris in the fall. Remove and destroy any affected plants as soon as they are observed.
4. Practice crop rotation. Do not plant tomatoes, potatoes, and celery in succession. All of these crops are susceptible.
5. Use a copper-based fungicide. Apply when symptoms are first identified. Reapply at 7–10 day intervals.
Symptoms and Diagnosis
One of the first symptoms of late blight is watersoaked patches on older leaves. Late blight attacks the older leaves first, then spreads to the fruit. Green-black watery patches develop on the upper surfaces of older leaves. These patches will enlarge quickly, and in moist weather, a downy growth may develop on the underside of the leaf. On the fruit, you will see rough, firm, dark-colored spots.
Life Cycle
The fungus overwinters on tomato and potato plant debris, including potato tubers. The fungus can produce spores over a broad range of temperatures although spores are most infective at temperatures of 68 degrees F with high humidity. The spores are transmitted by water or are wind blown and may be introduced from diseased plants in nearby gardens. The fungus invades the plant through leaf stomata. Infection rarely occurs when temperatures are higher than 80 degrees F and humidity is less than 90%.
Integrated Pest Management Strategies
1. Plant resistant varieties. Several tomato varieties are designated as resistant to late blight.
2. Avoid overhead watering. Avoid working around plants when they are wet. Both of these practices can spread the fungal spores from plant to plant.
3. Clean up all garden debris in the fall. Remove and destroy any affected plants as soon as they are observed.
4. Practice crop rotation. Do not plant tomatoes, potatoes, and celery in succession. All of these crops are susceptible.
5. Use a copper-based fungicide. Apply when symptoms are first identified. Reapply at 7–10 day intervals.
0
0
文章
Dummer. ゛☀
2017年09月19日
If your tomato plants yellow and wilt on one side of the plant or one side of a leaf, they may have Fusarium wilt. Fusarium wilt on tomatoes is caused by Fusarium oxysporumsp. lycopersici. It is a soilborn fungus that is found throughout the United States, especially in warm regions of the country. The organism is specific for tomato and is very longlived in all regions of the United States. The disease develops more quickly in soils that are high in nitrogen and low in potassium. In addition, plants grown in sandy soils tend to contract this disease more often.
Symptoms and Diagnosis
Fusarium often causes yellowing on one side of the plant or leaf. Yellowing begins with the older, bottom leaves, followed by wilting, browning, and defoliation. Growth is typically stunted, and little or no fruit develops. Brown, vascular tissue can be found when the infected stem is cut at its base. Infected plants often die before maturing.
Life Cycle
Fusarium fungi survive in the soil or associated with plant debris for up to ten years. Disease development is favored by warm soil temperatures, and symptoms are most prevalent when temperatures range from 80–90 degrees F. The fungi enter the plants through their roots and are then spread throughout the plant by the plant's water-conducting vessels.
Integrated Pest Management Strategies
1. Plant resistant varieties. These varieties are labeled VF and include cultivars such as ‘Spring Giant’, ‘Burpee VF’, ‘Supersonic’, ‘Celebrity’, ‘Manalucie’, ‘Better Boy’, and ‘Small Fry’.
2. Remove infected plants from the garden. Removal of infected plants will help limit the disease's spread. Soil sterilization or fumigation will eliminate wilt fungi from the soil but are impractical for home gardeners. Soil replacement should be considered.
3. Avoid over-application of high nitrogen fertilizers. High soil nitrogen levels accompanied by low potassium levels can increase susceptibility to the fungus. Use a soil test to determine potassium levels and other nutrient deficiencies.
4. Avoid activity in wet plantings. Movement of wet soil from place to place via shoes or tools will spread the disease.
5. Sanitize stakes and tomato cages at the end of the season. Avoid using soil-encrusted tools and supports season after season. A thorough cleaning with water will reduce most risk of transmitting the disease.
6. For four years, do not plant solanaceous plants in the area where infection occurred. Tomato, potato, pepper, and eggplant are all susceptible to the disease and may allow its survival year after year in the same planting area.
Symptoms and Diagnosis
Fusarium often causes yellowing on one side of the plant or leaf. Yellowing begins with the older, bottom leaves, followed by wilting, browning, and defoliation. Growth is typically stunted, and little or no fruit develops. Brown, vascular tissue can be found when the infected stem is cut at its base. Infected plants often die before maturing.
Life Cycle
Fusarium fungi survive in the soil or associated with plant debris for up to ten years. Disease development is favored by warm soil temperatures, and symptoms are most prevalent when temperatures range from 80–90 degrees F. The fungi enter the plants through their roots and are then spread throughout the plant by the plant's water-conducting vessels.
Integrated Pest Management Strategies
1. Plant resistant varieties. These varieties are labeled VF and include cultivars such as ‘Spring Giant’, ‘Burpee VF’, ‘Supersonic’, ‘Celebrity’, ‘Manalucie’, ‘Better Boy’, and ‘Small Fry’.
2. Remove infected plants from the garden. Removal of infected plants will help limit the disease's spread. Soil sterilization or fumigation will eliminate wilt fungi from the soil but are impractical for home gardeners. Soil replacement should be considered.
3. Avoid over-application of high nitrogen fertilizers. High soil nitrogen levels accompanied by low potassium levels can increase susceptibility to the fungus. Use a soil test to determine potassium levels and other nutrient deficiencies.
4. Avoid activity in wet plantings. Movement of wet soil from place to place via shoes or tools will spread the disease.
5. Sanitize stakes and tomato cages at the end of the season. Avoid using soil-encrusted tools and supports season after season. A thorough cleaning with water will reduce most risk of transmitting the disease.
6. For four years, do not plant solanaceous plants in the area where infection occurred. Tomato, potato, pepper, and eggplant are all susceptible to the disease and may allow its survival year after year in the same planting area.
0
0
文章
Dummer. ゛☀
2017年09月19日
Clubroot is a fungal disease that affects a number of plants in the cabbage family including cabbages, radish, mustard and ornamentals such as candytuft. It is caused by the fungus Plasmodiophora brassicae and gets its name from the club-like roots it induces in infected plants. Its diagnosis is often missed as the infected plant part, the roots, are underground and out of sight.
Symptoms and Diagnosis
The first symptom is usually wilting during average daily conditions but recovery at night. The older leaves may yellow and die and the plants look stunted. Examination of the root system reveals enlarged roots that make them look club-like and reduced feeder roots. The reduction in feeder roots as well as disruption of the water conducting tissue in the roots causes the drought-like symptoms. Development of the disease if favored by a low soil pH (below 7.0), cool soil, and excess soil moisture. The organism can survive in the soil for over 10 years. Since most soils in the St. Louis area are above a pH of 7 the disease is rare in our area.
Life Cycle
Clubroot is a soil-borne fungus that infects plants through root hairs by zoospores. After infection the roots enlarge and many spores are produced in the swollen roots. The mobile zoospores can re-infect other roots on the plant or nearby plants. Late in the season resting spores are produced. When roots die and decay the resting spores are released into the soil where they can survive for many years and be transported through the soil by water movement and garden equipment.
Integrated Pest Management Strategies
1. Remove diseased plants. The disease organism can reside in the soil for many years so although quick removal of diseased plants is recommended the disease may return if plants in the cabbage family are planted in the infested soil the following year. Also remove any cabbage family weeds such as wild mustard, which can harbor the disease.
2. Add lime. Since problems are more severe in acid soils (pH 5.0-7.0) adding lime to acid soils can help control the disease.
3. Rotate crops Rotate where you grow cabbage, radishes, mustards, etc in your garden. Wait 5-6 years before replanting in an area.
Symptoms and Diagnosis
The first symptom is usually wilting during average daily conditions but recovery at night. The older leaves may yellow and die and the plants look stunted. Examination of the root system reveals enlarged roots that make them look club-like and reduced feeder roots. The reduction in feeder roots as well as disruption of the water conducting tissue in the roots causes the drought-like symptoms. Development of the disease if favored by a low soil pH (below 7.0), cool soil, and excess soil moisture. The organism can survive in the soil for over 10 years. Since most soils in the St. Louis area are above a pH of 7 the disease is rare in our area.
Life Cycle
Clubroot is a soil-borne fungus that infects plants through root hairs by zoospores. After infection the roots enlarge and many spores are produced in the swollen roots. The mobile zoospores can re-infect other roots on the plant or nearby plants. Late in the season resting spores are produced. When roots die and decay the resting spores are released into the soil where they can survive for many years and be transported through the soil by water movement and garden equipment.
Integrated Pest Management Strategies
1. Remove diseased plants. The disease organism can reside in the soil for many years so although quick removal of diseased plants is recommended the disease may return if plants in the cabbage family are planted in the infested soil the following year. Also remove any cabbage family weeds such as wild mustard, which can harbor the disease.
2. Add lime. Since problems are more severe in acid soils (pH 5.0-7.0) adding lime to acid soils can help control the disease.
3. Rotate crops Rotate where you grow cabbage, radishes, mustards, etc in your garden. Wait 5-6 years before replanting in an area.
0
0
文章
Dummer. ゛☀
2017年09月19日
Oak wilt is a systematic disease caused by a fungus, Ceratocystis fagacearum. The fungus invades the water-conducting tissues of oak trees. The black oak group (red, black, scarlet, and pin oaks) is more susceptible than the white oak group (white, bur, chinkapin, and swamp oaks). Oak wilt ranges from Minnesota east to Pennsylvania, south to South Carolina and Tennessee, west to central Texas, and north through Kansas and Nebraska. Infection through wounds is especially critical between April 1 and July 1 and during later periods of summer rains. There is no cure for oak wilt, so control consists of measures to prevent the disease from spreading.
Symptoms and Diagnosis
The first symptoms include a dull-green appearance of wilted leaves. Later, wilted leaves curl and turn tan or bronze, beginning at the outer portions of the leaves. The base of the leaf and the main vein will remain green for some time. Defoliation may be delayed for weeks. Peeled bark or a cut branch from an infected tree may show a brown or black discoloration in the outer annual sapwood ring. Positive diagnosis of oak wilt requires laboratory culturing and identification.
Life Cycle
The fungus spreads through the water-conducting vessels of the sapwood. The tree’s response to the presence of the fungus results in the disruption of sap flow, and the affected areas wilt. Oak wilt can spread to healthy trees through natural grafts with roots of adjacent oaks of the same species up to 50 feet apart. Root grafts join together the vascular systems of the trees, forming a network through which the disease can spread. The disease can also spread by sap-feeding beetles that transmit spores of the oak wilt fungus from infected trees to healthy ones.
Integrated Pest Management Strategies
1. There is no cure for the disease. If oak wilt is suspected, a laboratory test is needed to make a positive diagnosis. Contact an arborist or an extension office on sampling procedures and fees associated with the laboratory testing. Samples of freshly wilted stems (not dead) about 1/2 to 1 inch in diameter and 6–10 inches in length are needed for the laboratory test.
2. Sever root grafts. Destroying root grafts with chemicals or by mechanical means can slow the spread of the disease from diseased to healthy oak trees. Since there is a delay between infection and the appearance of symptoms, destroying root grafts is a gamble. Root grafts do not occur between the black oak and white oak groups.
3. Improve plant vigor. Your best guard against getting oak wilt is to keep your oak trees, especially oaks in the black oak group, healthy. If your oak trees do not appear in the best of health, have an experienced arborist evaluate their health and recommend a course of action. Mild cases in white oaks may respond to pruning of diseased wood plus fertilizing and watering to increase plant vigor.
4. Avoid pruning or wounding the tree between mid-March and late June. During this time of year, insects carrying the disease are attracted by the sap which flows freely from wounds. The safest time to prune oaks is during winter before mid-March.
5. Plant white oaks rather than the more susceptible black oaks. If you do plant black oaks, be certain they are more than 50 feet apart to eliminate future disease spread via root grafts. Limit black oak use where oak wilt is prevalent.
Symptoms and Diagnosis
The first symptoms include a dull-green appearance of wilted leaves. Later, wilted leaves curl and turn tan or bronze, beginning at the outer portions of the leaves. The base of the leaf and the main vein will remain green for some time. Defoliation may be delayed for weeks. Peeled bark or a cut branch from an infected tree may show a brown or black discoloration in the outer annual sapwood ring. Positive diagnosis of oak wilt requires laboratory culturing and identification.
Life Cycle
The fungus spreads through the water-conducting vessels of the sapwood. The tree’s response to the presence of the fungus results in the disruption of sap flow, and the affected areas wilt. Oak wilt can spread to healthy trees through natural grafts with roots of adjacent oaks of the same species up to 50 feet apart. Root grafts join together the vascular systems of the trees, forming a network through which the disease can spread. The disease can also spread by sap-feeding beetles that transmit spores of the oak wilt fungus from infected trees to healthy ones.
Integrated Pest Management Strategies
1. There is no cure for the disease. If oak wilt is suspected, a laboratory test is needed to make a positive diagnosis. Contact an arborist or an extension office on sampling procedures and fees associated with the laboratory testing. Samples of freshly wilted stems (not dead) about 1/2 to 1 inch in diameter and 6–10 inches in length are needed for the laboratory test.
2. Sever root grafts. Destroying root grafts with chemicals or by mechanical means can slow the spread of the disease from diseased to healthy oak trees. Since there is a delay between infection and the appearance of symptoms, destroying root grafts is a gamble. Root grafts do not occur between the black oak and white oak groups.
3. Improve plant vigor. Your best guard against getting oak wilt is to keep your oak trees, especially oaks in the black oak group, healthy. If your oak trees do not appear in the best of health, have an experienced arborist evaluate their health and recommend a course of action. Mild cases in white oaks may respond to pruning of diseased wood plus fertilizing and watering to increase plant vigor.
4. Avoid pruning or wounding the tree between mid-March and late June. During this time of year, insects carrying the disease are attracted by the sap which flows freely from wounds. The safest time to prune oaks is during winter before mid-March.
5. Plant white oaks rather than the more susceptible black oaks. If you do plant black oaks, be certain they are more than 50 feet apart to eliminate future disease spread via root grafts. Limit black oak use where oak wilt is prevalent.
0
0
文章
Dummer. ゛☀
2017年09月19日
Oak leaf blister (oak leaf curl) is a fungal leaf disease caused by the fungus Taphrina caerulescens. Circular, raised areas ranging up to 2 inches in diameter are scattered over the upper leaf surface. During cool wet springs, almost all species of oak are subject to the leaf blister disease. Members of the red oak family are particularly susceptible to infection. The disease is closely related to Taprina deformans which causes peach leaf curl.
Symptoms and Diagnosis
Blister-like, circular, raised areas appear scattered on the upper leaf surface. This raised area causes a corresponding depression on the lower leaf surface at the same site and of the same size. The color of the upper convex area is yellowish white while the bottom concave area is yellowish brown.
Leaves with numerous spots may fall prematurely to the ground. If well-established trees defoliate before midsummer, they will sometimes leaf out later in the season. When defoliation occurs in late summer, leaf loss will have little impact on the overall health of the tree.
Life Cycle
During mid-spring, microscopic spores are produced in leaf spots. These spores are carried by wind and splashing raindrops onto bud scales and twigs where they remain in a dormant stage until the following early spring. At this time, rain washes the spores onto young leaves where infection takes place. Depending on weather conditions, small circular spots begin to develop in 2 to 4 weeks. Spores produced on these spots will lodge in bud scales and again remain resting until the following spring. Cool wet weather is required for germination on young leaves, and if these conditions continue, severe infection can occur. If weather conditions are not favorable for spore germination shortly after bud break, only minor infection will occur. As the leaves mature, they become more resistant to infection.
Integrated Pest Management Strategies
1. Maintain plant vigor. Keep the tree well watered during drought conditions (approximately 1 inch of water per week) and well-drained during periods of heavy rain. Fertilize according to soil test recommendations. Apply nitrogen every 3 to 5 years for mature shade trees.
2. General health. Oak leaf blister does not seriously affect the overall health of the tree unless the tree is repeatedly defoliated in successive years. Even if this occurs, the second set of leaves should emerge at a time when conditions are not conducive to reinfection of leaves and newly formed bud scales.
3. Fungicides. A single application of a fungicide applied in the spring at the time of bud-swelling is usually adequate. Apply with a power sprayer and coat buds and twigs thoroughly for good control. chlorothalonil (Daconil) is currently registered for use in controlling oak leaf blister. Fungicides will not be effective if applied after bud break. As with the use of all chemicals, carefully read and follow the manufacturer’s directions.
Symptoms and Diagnosis
Blister-like, circular, raised areas appear scattered on the upper leaf surface. This raised area causes a corresponding depression on the lower leaf surface at the same site and of the same size. The color of the upper convex area is yellowish white while the bottom concave area is yellowish brown.
Leaves with numerous spots may fall prematurely to the ground. If well-established trees defoliate before midsummer, they will sometimes leaf out later in the season. When defoliation occurs in late summer, leaf loss will have little impact on the overall health of the tree.
Life Cycle
During mid-spring, microscopic spores are produced in leaf spots. These spores are carried by wind and splashing raindrops onto bud scales and twigs where they remain in a dormant stage until the following early spring. At this time, rain washes the spores onto young leaves where infection takes place. Depending on weather conditions, small circular spots begin to develop in 2 to 4 weeks. Spores produced on these spots will lodge in bud scales and again remain resting until the following spring. Cool wet weather is required for germination on young leaves, and if these conditions continue, severe infection can occur. If weather conditions are not favorable for spore germination shortly after bud break, only minor infection will occur. As the leaves mature, they become more resistant to infection.
Integrated Pest Management Strategies
1. Maintain plant vigor. Keep the tree well watered during drought conditions (approximately 1 inch of water per week) and well-drained during periods of heavy rain. Fertilize according to soil test recommendations. Apply nitrogen every 3 to 5 years for mature shade trees.
2. General health. Oak leaf blister does not seriously affect the overall health of the tree unless the tree is repeatedly defoliated in successive years. Even if this occurs, the second set of leaves should emerge at a time when conditions are not conducive to reinfection of leaves and newly formed bud scales.
3. Fungicides. A single application of a fungicide applied in the spring at the time of bud-swelling is usually adequate. Apply with a power sprayer and coat buds and twigs thoroughly for good control. chlorothalonil (Daconil) is currently registered for use in controlling oak leaf blister. Fungicides will not be effective if applied after bud break. As with the use of all chemicals, carefully read and follow the manufacturer’s directions.
0
0
文章
Dummer. ゛☀
2017年09月19日
Worldwide, Nectria fungi cause several common canker and dieback diseases, especially in hardwood trees. Nectria canker, which is caused by the fungus, Nectria galligena, may occur on over 60 species of trees and shrubs including apple, ash, birch, dogwood, elm, sweet gum, holly, maple, pear and walnut. A similar disease infects members of the magnolia family. Nectria canker is usually not a fatal disease, but it can cause considerable damage as the cankered area is weakened and susceptible to breakage. It may also adversely affect the appearance of the affected plant. This disease is important commercially as it reduces the quality and quantity of forest products.
Another member of the Nectria genus, Nectria cinnabarina, causes the disease Nectria dieback. Also known as coral spot Nectria canker or Nectria canker, this disease occurs on many plant species, including apple, ash, barberry, birch, boxwood, crabapple, elm, hickory, honey locust, linden, maple, pear, rose and Japanese zelkova. Nectria cinnabarina usually grows as a saprophyte on dead wood, but if a plant is wounded or otherwise stressed, the fungus becomes an opportunistic weak parasite, producing cankers and causing dieback of twigs and branches. Maples are especially affected by this disease as are recently wounded or severely pruned trees and shrubs, urban ornamentals and new transplants of other species.
Symptoms and Diagnosis
Although it is most common in spring and fall, the Nectria fungus can infect plants throughout the year as long as there is sufficient moisture and the temperature is above freezing. Plants that are stressed by cold, drought, mechanical injuries or other disease are especially susceptible. Infections may be worse in autumn and winter when the host plant is dormant and wound recovery is weaker than in the growing season.
The first symptom of a Nectria infection is a depressed discolored area of bark near wounds or at the base of dead twigs or branches. These cankers are usually not noticed until other symptoms appear.
The first easily visible signs of Nectria canker are small creamy white or red to reddish orange fruiting structures and the development of callus tissue. This callus tissue is produced as the host plant attempts to isolate the fungus. If the callus does not isolate the infection, the fungus will continue to grow into healthy wood and the plant will respond by growing another ridge of callus tissue. This alternation of fungal growth and callus ridge, which may occur for many years, results in a rounded or elongated target-like shape. The bark of older ridges may decay and weather away exposing the ridges of wood underneath. This disease grows slowly and larger stems are rarely girdled, although multiple lesions may grow together and kill a branch or the entire plant. Plants that are stressed are most severely affected by the disease. This fungus may also affect apple fruit causing it to rot during storage.
The first obvious sign of Nectria dieback may not occur until spring when the plant begins to grow. Affected twigs, branches, or even entire plants will not produce leaves or may wilt suddenly. Larger branches or small trees may be girdled and killed. The fungus produces reproductive structures that vary in color from creamy, coral pink, pink-orange, light purplish red or orange-red and that darken as they mature.
Life Cycle
Nectria galligena overwinters in the callus tissue growing slowly while its host is dormant. During moist periods, creamy white cushion-like fruiting structures will develop. These are followed by a second type of reproductive structure, which is red to reddish orange, pin-head sized and lemon-shaped, in autumn through spring. During rain or other moist weather, spores are released and dispersed by wind or water infecting susceptible plants through natural openings such as leaf scars or through wounds from improper pruning, sunscald, storm damage, frost cracks or other mechanical damage. As the fungus grows, it kills bark, cambium, and the outermost sapwood.
The life cycle of the Nectria dieback fungus is similar to that of Nectria canker. Creamy to coral pink to pink-orange or light purplish red spore-producing structures develop in spring or early summer. These will age to tan, brown, or nearly black. Orange-red fruiting structures, which mature to dark reddish brown and may persist through winter, are produced in summer and autumn. Both structures release spores that are dispersed by water and can invade susceptible tissue producing cankers and dieback.
Integrated Pest Management Strategies
1. Proper selection. Choose trees and shrubs that are well adapted to the climate of the area to minimize infection due to freeze damage and other environmental stresses.
2. Maintain plant vigor. Keep plants healthy and growing vigorously by using good cultural techniques. These include choosing the appropriate planting site, watering during dry periods, using mulch around the base of the tree or shrub and fertilizing and pruning properly. Pruning is best done in late winter. Avoid pruning in spring when higher moisture can increase risk of infection or in late summer and autumn, which can delay the plant’s natural cold hardiness response. Minimize any wounding due to root pruning, transplanting or lawnmowers to reduce infection sites.
3. Prune. Prune out branch cankers during dry periods when conditions are unfavorable for infection. Disinfect pruning tools in a 1-part bleach to 9-parts water solution between each cut.
Another member of the Nectria genus, Nectria cinnabarina, causes the disease Nectria dieback. Also known as coral spot Nectria canker or Nectria canker, this disease occurs on many plant species, including apple, ash, barberry, birch, boxwood, crabapple, elm, hickory, honey locust, linden, maple, pear, rose and Japanese zelkova. Nectria cinnabarina usually grows as a saprophyte on dead wood, but if a plant is wounded or otherwise stressed, the fungus becomes an opportunistic weak parasite, producing cankers and causing dieback of twigs and branches. Maples are especially affected by this disease as are recently wounded or severely pruned trees and shrubs, urban ornamentals and new transplants of other species.
Symptoms and Diagnosis
Although it is most common in spring and fall, the Nectria fungus can infect plants throughout the year as long as there is sufficient moisture and the temperature is above freezing. Plants that are stressed by cold, drought, mechanical injuries or other disease are especially susceptible. Infections may be worse in autumn and winter when the host plant is dormant and wound recovery is weaker than in the growing season.
The first symptom of a Nectria infection is a depressed discolored area of bark near wounds or at the base of dead twigs or branches. These cankers are usually not noticed until other symptoms appear.
The first easily visible signs of Nectria canker are small creamy white or red to reddish orange fruiting structures and the development of callus tissue. This callus tissue is produced as the host plant attempts to isolate the fungus. If the callus does not isolate the infection, the fungus will continue to grow into healthy wood and the plant will respond by growing another ridge of callus tissue. This alternation of fungal growth and callus ridge, which may occur for many years, results in a rounded or elongated target-like shape. The bark of older ridges may decay and weather away exposing the ridges of wood underneath. This disease grows slowly and larger stems are rarely girdled, although multiple lesions may grow together and kill a branch or the entire plant. Plants that are stressed are most severely affected by the disease. This fungus may also affect apple fruit causing it to rot during storage.
The first obvious sign of Nectria dieback may not occur until spring when the plant begins to grow. Affected twigs, branches, or even entire plants will not produce leaves or may wilt suddenly. Larger branches or small trees may be girdled and killed. The fungus produces reproductive structures that vary in color from creamy, coral pink, pink-orange, light purplish red or orange-red and that darken as they mature.
Life Cycle
Nectria galligena overwinters in the callus tissue growing slowly while its host is dormant. During moist periods, creamy white cushion-like fruiting structures will develop. These are followed by a second type of reproductive structure, which is red to reddish orange, pin-head sized and lemon-shaped, in autumn through spring. During rain or other moist weather, spores are released and dispersed by wind or water infecting susceptible plants through natural openings such as leaf scars or through wounds from improper pruning, sunscald, storm damage, frost cracks or other mechanical damage. As the fungus grows, it kills bark, cambium, and the outermost sapwood.
The life cycle of the Nectria dieback fungus is similar to that of Nectria canker. Creamy to coral pink to pink-orange or light purplish red spore-producing structures develop in spring or early summer. These will age to tan, brown, or nearly black. Orange-red fruiting structures, which mature to dark reddish brown and may persist through winter, are produced in summer and autumn. Both structures release spores that are dispersed by water and can invade susceptible tissue producing cankers and dieback.
Integrated Pest Management Strategies
1. Proper selection. Choose trees and shrubs that are well adapted to the climate of the area to minimize infection due to freeze damage and other environmental stresses.
2. Maintain plant vigor. Keep plants healthy and growing vigorously by using good cultural techniques. These include choosing the appropriate planting site, watering during dry periods, using mulch around the base of the tree or shrub and fertilizing and pruning properly. Pruning is best done in late winter. Avoid pruning in spring when higher moisture can increase risk of infection or in late summer and autumn, which can delay the plant’s natural cold hardiness response. Minimize any wounding due to root pruning, transplanting or lawnmowers to reduce infection sites.
3. Prune. Prune out branch cankers during dry periods when conditions are unfavorable for infection. Disinfect pruning tools in a 1-part bleach to 9-parts water solution between each cut.
0
0
文章
Dummer. ゛☀
2017年09月19日
Dutch elm disease is a wilt disease caused by the fungus, Ceratocystis ulmi. It was described in Ohio in 1930. By the 1980's, it could be found in most of the U.S. It is a serious and fatal disease of American elms. Even after years of study, there is no effective cure for the disease.
Symptoms and Diagnosis
Symptoms develop rapidly during a period of 4–6 weeks after leaves reach full size. The first visible symptoms are yellowing of foliage followed by wilting and browning, a condition called flagging. Usually a single branch is affected first; wilted branches die rapidly and leaves brown, curl, and often drop prematurely. The symptoms spread to nearby branches and then to one whole part of the tree. The entire tree finally wilts and dies. This progression of symptoms may develop in one season or may take several years. Positive diagnosis of the disease requires a laboratory test to culture the fungal pathogen.
Life Cycle
The fungus is primarily dependent on insectvectored transmission from tree to tree over long distances. There are 2 vectors for the fungus in North America, the native American elm bark beetle and the less prevalent European elm bark beetle. Both of these beetles feed and breed under the bark of living or recently dead elm trees or logs. They carry the spores of the fungus from infected trees and innoculate healthy trees as they feed. Both species of elm bark beetles are effective carriers. The cycle of infection by the fungus is tied to the life cycle of the vectors. The beetles breed in recently dead elm wood or weakened living trees. If the fungus is present in breeding sites, emerging beetles will carry spores to healthy elms and introduce the fungus in feeding sites on young twigs. The beetles can fly up to 1/4 mile in search of feeding or breeding sites, but they may be blown many miles by winds. The disease may also spread by root grafts from a diseased elm tree to a healthy elm tree provided that the root systems overlap.
Integrated Pest Management Strategies
1. There is no cure for the disease. If your elm tree has leaves yellowing or wilting on one or more branches, cut off several small branches and look for brown streaking in the sapwood. If brown streaking is evident, a laboratory test is suggested for positive identification. This disease may be confused with other canker and wilt pathogens of elm.
2. Maintain plant health. Provide adequate amounts of water and fertilizer. Mild cases of Dutch elm disease may respond to pruning of diseased wood if less than 5% of the tree is infected. Control the insect vectors. Systemic fungicides injected into the tree at 1–3 year intervals have proven beneficial in providing protection. An arborist should be consulted to discuss costs and potential benefits.
3. Remove diseased trees. Severe cases require complete removal of the tree. Wood should not be saved for firewood. It should be chipped to destroy the beetle’s breeding place. Nearby American elms may also be infected through root grafts. Destroying root grafts by mechanical severing can slow the spread of the disease, if done before the fungus has moved into healthy elm trees. This may not be practical in a home setting.
4. Replace diseased trees with varieties resistant to Dutch elm disease. The true Chinese elm, Ulmus parviflora, a tree with multi-colored bark, is one choice. A related tree with a vase shape similar to American elm is the Japanese zelkova, Zelkova serrata. Both are resistant to Dutch elm disease but not immune.
Symptoms and Diagnosis
Symptoms develop rapidly during a period of 4–6 weeks after leaves reach full size. The first visible symptoms are yellowing of foliage followed by wilting and browning, a condition called flagging. Usually a single branch is affected first; wilted branches die rapidly and leaves brown, curl, and often drop prematurely. The symptoms spread to nearby branches and then to one whole part of the tree. The entire tree finally wilts and dies. This progression of symptoms may develop in one season or may take several years. Positive diagnosis of the disease requires a laboratory test to culture the fungal pathogen.
Life Cycle
The fungus is primarily dependent on insectvectored transmission from tree to tree over long distances. There are 2 vectors for the fungus in North America, the native American elm bark beetle and the less prevalent European elm bark beetle. Both of these beetles feed and breed under the bark of living or recently dead elm trees or logs. They carry the spores of the fungus from infected trees and innoculate healthy trees as they feed. Both species of elm bark beetles are effective carriers. The cycle of infection by the fungus is tied to the life cycle of the vectors. The beetles breed in recently dead elm wood or weakened living trees. If the fungus is present in breeding sites, emerging beetles will carry spores to healthy elms and introduce the fungus in feeding sites on young twigs. The beetles can fly up to 1/4 mile in search of feeding or breeding sites, but they may be blown many miles by winds. The disease may also spread by root grafts from a diseased elm tree to a healthy elm tree provided that the root systems overlap.
Integrated Pest Management Strategies
1. There is no cure for the disease. If your elm tree has leaves yellowing or wilting on one or more branches, cut off several small branches and look for brown streaking in the sapwood. If brown streaking is evident, a laboratory test is suggested for positive identification. This disease may be confused with other canker and wilt pathogens of elm.
2. Maintain plant health. Provide adequate amounts of water and fertilizer. Mild cases of Dutch elm disease may respond to pruning of diseased wood if less than 5% of the tree is infected. Control the insect vectors. Systemic fungicides injected into the tree at 1–3 year intervals have proven beneficial in providing protection. An arborist should be consulted to discuss costs and potential benefits.
3. Remove diseased trees. Severe cases require complete removal of the tree. Wood should not be saved for firewood. It should be chipped to destroy the beetle’s breeding place. Nearby American elms may also be infected through root grafts. Destroying root grafts by mechanical severing can slow the spread of the disease, if done before the fungus has moved into healthy elm trees. This may not be practical in a home setting.
4. Replace diseased trees with varieties resistant to Dutch elm disease. The true Chinese elm, Ulmus parviflora, a tree with multi-colored bark, is one choice. A related tree with a vase shape similar to American elm is the Japanese zelkova, Zelkova serrata. Both are resistant to Dutch elm disease but not immune.
0
0
文章
Dummer. ゛☀
2017年09月19日
Unlike other blights, chestnut blight is not just associated with shoot dieback; it can kill twigs and branches of any size. It is actually a canker disease caused by a fungus, Cryphonectria parasitica, formerly known as Endothia parasitica.
The significance of chestnut blight is tied to the species it decimated- the American chestnut, Castanea dentata. In 1900 the American chestnut was not only the dominant species of eastern hardwood forests in the U.S., it was the most important tree commercially, because of its beautiful, rot resistant lumber, because of the quantities of edible nuts it produced, and because of the rapidity with which it could repopulate clear-cut areas of the forest.
Chestnut blight was first identified in the United States in New York City in 1904, but it probably entered the country earlier, in the late 1800s on imported Asian chestnuts. By 1950, 99.9% of American chestnuts were reduced to either dead stumps or stumps with adventitious sprouts arising from the roots surrounding them. Many of these stumps persist today and are still sending up diseased sprouts that are as susceptible to chestnut canker as the parent plant.
Other species that are highly susceptible to chestnut blight are the Allegheny chestnut (C. pumila), the bush chinkapin chestnut (C. alnifolia) and the European chestnut (C. sativa). The last species, Castanea sativa, is not native to the U.S. and is restricted here. Some oaks are host to the disease; these include live, post, scarlet and white oaks. It is also occasionally found on shagbark hickory, red maple and staghorn sumac.
Chinese and Japanese chestnuts have shown some resistance to chestnut blight; for these Cryphonectria parasitica is a stress pathogen only. No other species of chestnut, however, has the characteristics necessary to replace the American chestnut as a forest tree or as an ornamental. The European chestnut, Castanea sativa, does share some of these characteristics, but it is also susceptible to chestnut blight and its importation into this country is restricted.
Symptoms and Diagnosis
Obvious symptoms on the American chestnut include flagging (the yellowing and dying of individual branches) and dead leaves that hang onto branches over the first winter. On young trees and on juvenile branches of mature trees, cankers appear as yellowish to reddish areas in the bark around branch crotches; these cankers can girdle and kill a branch within a few weeks. On mature trees, cankers are initially imperceptible unless the bark is stripped off. Later, as the canker expands, the bark swells and cracks, eventually falling off. Yellowish brown fruiting bodies may be visible on the surface of the bark around the canker or in the cracks in the bark. In American chestnuts, the trunk is eventually girdled which can occur within a few weeks for young trees and within a few years for mature trees. Few last longer than four years. Suckers usually shoot up from the surrounding roots of American chestnuts providing a constant supply of susceptible tissue for the pathogen’s continued existence; this suckering does not occur in other species.
Live oaks decline slowly. Foliage at the crown is chlorotic and sparse with dead branches. Cankers are difficult to discern.
Severe dieback can occur on post oaks and scarlet oaks, but smaller cankers or superficial cankers are more common. Cankers on post oak are more pronounced than on live oaks and the bark will usually slough off, while on scarlet oaks the cankers appear swollen and remain covered with bark. Swelling can also indicate cankers on white oak.
Infected Chinese and Japanese chestnuts are usually stressed trees. Chinese chestnuts display twig or branch dieback or targetlike cankers, and bark will eventually slough off.
Buff to orangish flat, mycelial fans in the diseased bark are characteristic of chestnut blight although positive diagnosis of the disease requires a laboratory test to culture the fungal pathogen.
Life Cycle
The success of this disease must be attributed, as least in part, to its ability to spread in so many different ways. Vectors include insects, birds, other animals, wind, and rain. Ascospores or conidia enter fresh wounds, probably caused by insects, usually in bark surrounding branches and twigs. Buff to orange mycelial fans then spread into living bark and cambium tissue. As cell death occurs, the fungus spreads into living tissue. Thus, as branches and twigs are girdled, the canker moves toward living tissue–ultimately to the main trunk of the tree. It does not, however, invade the crown.
The environmental conditions necessary to the survival of the chestnut blight pathogen seem virtually unlimited. No condition in which a chestnut can live discourages or suppresses the pathogen. It can live anywhere chestnuts live and can reproduce at any time of the year.
Integrated Pest Management Strategies
1 There is no cure for chestnut blight. Once the pathogen is present in an area, and it is already present in most areas, any American chestnut is at extreme risk; therefore, do not plant them. Other species should only be planted in preferred growing conditions; stressed sites will place them at risk.
2. Choose resistant species. Although the search for a blight resistant American chestnut has been ongoing for nearly a century, no blight resistant American chestnuts are currently on the market. Specimens sold as "blight free" have not been exposed to the disease (i.e., blight-free does not mean blight resistant).
The significance of chestnut blight is tied to the species it decimated- the American chestnut, Castanea dentata. In 1900 the American chestnut was not only the dominant species of eastern hardwood forests in the U.S., it was the most important tree commercially, because of its beautiful, rot resistant lumber, because of the quantities of edible nuts it produced, and because of the rapidity with which it could repopulate clear-cut areas of the forest.
Chestnut blight was first identified in the United States in New York City in 1904, but it probably entered the country earlier, in the late 1800s on imported Asian chestnuts. By 1950, 99.9% of American chestnuts were reduced to either dead stumps or stumps with adventitious sprouts arising from the roots surrounding them. Many of these stumps persist today and are still sending up diseased sprouts that are as susceptible to chestnut canker as the parent plant.
Other species that are highly susceptible to chestnut blight are the Allegheny chestnut (C. pumila), the bush chinkapin chestnut (C. alnifolia) and the European chestnut (C. sativa). The last species, Castanea sativa, is not native to the U.S. and is restricted here. Some oaks are host to the disease; these include live, post, scarlet and white oaks. It is also occasionally found on shagbark hickory, red maple and staghorn sumac.
Chinese and Japanese chestnuts have shown some resistance to chestnut blight; for these Cryphonectria parasitica is a stress pathogen only. No other species of chestnut, however, has the characteristics necessary to replace the American chestnut as a forest tree or as an ornamental. The European chestnut, Castanea sativa, does share some of these characteristics, but it is also susceptible to chestnut blight and its importation into this country is restricted.
Symptoms and Diagnosis
Obvious symptoms on the American chestnut include flagging (the yellowing and dying of individual branches) and dead leaves that hang onto branches over the first winter. On young trees and on juvenile branches of mature trees, cankers appear as yellowish to reddish areas in the bark around branch crotches; these cankers can girdle and kill a branch within a few weeks. On mature trees, cankers are initially imperceptible unless the bark is stripped off. Later, as the canker expands, the bark swells and cracks, eventually falling off. Yellowish brown fruiting bodies may be visible on the surface of the bark around the canker or in the cracks in the bark. In American chestnuts, the trunk is eventually girdled which can occur within a few weeks for young trees and within a few years for mature trees. Few last longer than four years. Suckers usually shoot up from the surrounding roots of American chestnuts providing a constant supply of susceptible tissue for the pathogen’s continued existence; this suckering does not occur in other species.
Live oaks decline slowly. Foliage at the crown is chlorotic and sparse with dead branches. Cankers are difficult to discern.
Severe dieback can occur on post oaks and scarlet oaks, but smaller cankers or superficial cankers are more common. Cankers on post oak are more pronounced than on live oaks and the bark will usually slough off, while on scarlet oaks the cankers appear swollen and remain covered with bark. Swelling can also indicate cankers on white oak.
Infected Chinese and Japanese chestnuts are usually stressed trees. Chinese chestnuts display twig or branch dieback or targetlike cankers, and bark will eventually slough off.
Buff to orangish flat, mycelial fans in the diseased bark are characteristic of chestnut blight although positive diagnosis of the disease requires a laboratory test to culture the fungal pathogen.
Life Cycle
The success of this disease must be attributed, as least in part, to its ability to spread in so many different ways. Vectors include insects, birds, other animals, wind, and rain. Ascospores or conidia enter fresh wounds, probably caused by insects, usually in bark surrounding branches and twigs. Buff to orange mycelial fans then spread into living bark and cambium tissue. As cell death occurs, the fungus spreads into living tissue. Thus, as branches and twigs are girdled, the canker moves toward living tissue–ultimately to the main trunk of the tree. It does not, however, invade the crown.
The environmental conditions necessary to the survival of the chestnut blight pathogen seem virtually unlimited. No condition in which a chestnut can live discourages or suppresses the pathogen. It can live anywhere chestnuts live and can reproduce at any time of the year.
Integrated Pest Management Strategies
1 There is no cure for chestnut blight. Once the pathogen is present in an area, and it is already present in most areas, any American chestnut is at extreme risk; therefore, do not plant them. Other species should only be planted in preferred growing conditions; stressed sites will place them at risk.
2. Choose resistant species. Although the search for a blight resistant American chestnut has been ongoing for nearly a century, no blight resistant American chestnuts are currently on the market. Specimens sold as "blight free" have not been exposed to the disease (i.e., blight-free does not mean blight resistant).
0
0
文章
Dummer. ゛☀
2017年09月18日
Sphaeropsis tip blight is caused by the fungus, Sphaeropsis sapinea (also known as Diplodia pinea). It is one of the most destructive fungal diseases of pine trees in the Midwest. It is most common on Austrian pine but can also damage Scotch pine (Scots pine), ponderosa, and mugo pine. If not controlled, over a period of years, it will weaken and perhaps kill the tree.
Symptoms and Diagnosis
Tip blight most commonly affects trees 13 or more years old that bear mature pine cones, but it can also affect younger trees. The most obvious symptom is the browning and stunting of the needles of the new growth. The needles are retained on the tree. Excess resin flow builds up on the dead twigs and needle bases. Small black pimples (pycnidia) about the size of fly specks are very noticeable on the bases of the browned needles, on the dead twigs, and on the cone scales. The pimples are the fruiting bodies of the fungus. Infection usually begins on the lower branches and moves up the tree. Sphaeropsis tip blight may be confused with pine tip moth damage. In the case of the latter, the fungal fruiting bodies will not be present, but moth larvae and tunneling in the shoots will be evident.
Life Cycle
Symptoms of tip dieback are most common in spring from April to mid-June when the young emerging needles are soft and tender. They are most vulnerable for the two weeks when the buds first open. Spores are released from the fruiting bodies (pycnidia) and are moved by splashing rain, wind, animals, and pruning equipment. They are dispersed throughout the year. Under very moist, humid conditions, the spores germinate and infect the needles. Once the fungus infects the needles, tissue is destroyed and shoots and needles are stunted. Infected second-year cones are a major source of inoculum. Infected cones are often observed on plants that show no other signs of infection. Latent infection is common and may be symptomless.
Integrated Pest Management Strategies
1. Keep trees healthy. Weakened trees are more susceptible to disease. Water during dry periods and fertilize according to soil test recommendations. Spores of Sphaeropsis sapinea are ever-present and can be found on the branches of most pine trees with the exception of white pine. Spores can infect without causing symptoms.
2. Use fungicidal sprays.Infection of new shoots may be reduced significantly with properly timed fungicidal sprays. Fixed copper or Bordeaux should be applied twice during the period when buds are opening. Apply in late April to early May, when the buds just begin to open. Repeat application in one to two weeks. Other pesticides registered for use include chlorothalonil (Daconil), mancozeb, and thiophanate methyl (Cleary 3336).
3. Replace with more resistant trees. When dead or dying trees are removed, replant with trees that are less susceptible to Sphaeropsis tip blight such as white pine, spruces, or junipers.
Symptoms and Diagnosis
Tip blight most commonly affects trees 13 or more years old that bear mature pine cones, but it can also affect younger trees. The most obvious symptom is the browning and stunting of the needles of the new growth. The needles are retained on the tree. Excess resin flow builds up on the dead twigs and needle bases. Small black pimples (pycnidia) about the size of fly specks are very noticeable on the bases of the browned needles, on the dead twigs, and on the cone scales. The pimples are the fruiting bodies of the fungus. Infection usually begins on the lower branches and moves up the tree. Sphaeropsis tip blight may be confused with pine tip moth damage. In the case of the latter, the fungal fruiting bodies will not be present, but moth larvae and tunneling in the shoots will be evident.
Life Cycle
Symptoms of tip dieback are most common in spring from April to mid-June when the young emerging needles are soft and tender. They are most vulnerable for the two weeks when the buds first open. Spores are released from the fruiting bodies (pycnidia) and are moved by splashing rain, wind, animals, and pruning equipment. They are dispersed throughout the year. Under very moist, humid conditions, the spores germinate and infect the needles. Once the fungus infects the needles, tissue is destroyed and shoots and needles are stunted. Infected second-year cones are a major source of inoculum. Infected cones are often observed on plants that show no other signs of infection. Latent infection is common and may be symptomless.
Integrated Pest Management Strategies
1. Keep trees healthy. Weakened trees are more susceptible to disease. Water during dry periods and fertilize according to soil test recommendations. Spores of Sphaeropsis sapinea are ever-present and can be found on the branches of most pine trees with the exception of white pine. Spores can infect without causing symptoms.
2. Use fungicidal sprays.Infection of new shoots may be reduced significantly with properly timed fungicidal sprays. Fixed copper or Bordeaux should be applied twice during the period when buds are opening. Apply in late April to early May, when the buds just begin to open. Repeat application in one to two weeks. Other pesticides registered for use include chlorothalonil (Daconil), mancozeb, and thiophanate methyl (Cleary 3336).
3. Replace with more resistant trees. When dead or dying trees are removed, replant with trees that are less susceptible to Sphaeropsis tip blight such as white pine, spruces, or junipers.
0
0
文章
Dummer. ゛☀
2017年09月18日
Rhizosphaera needlecast is caused by the fungus, Rhizosphaera kalkhoffii. The disease causes death and casting (dropping) of needles in spruces, especially Colorado spruce and occasionally white spruce. It is usually first evident on the lower branches of the tree and can cause severe defoliation and death of branches if allowed to persist. It rarely kills the tree.
Symptoms and Diagnosis
Infections take place in the spring, and symptoms show up about a year later. Infected 2-year old needles become spotted or mottled, some turning yellow and some developing a purplish brown color in late summer. Browning becomes general in late winter to early spring, and needles are prematurely shed during summer and fall, 12 to 15 months after initial infection. Black fruiting bodies are visible on discolored needles and even some green ones. The spores emerge from the stomates on the needles so appear in rows along the needles. Scattered lower branches are usually affected first and then browning progresses upward. Symptoms may be confused with spider mite damage. In the latter, mites and fine webbing may be visible; the lines of black fruiting bodies on the needles will also be absent.
Life Cycle
Rhizosphaera kalkhoffii overwinters in infected needles on the tree or ground. Spores are released from the infected needles in the spring, during wet weather. Spores are dispersed by splashing and dripping water. They infect newly emerging needles, as well as mature needles. Infection begins in spring, in April or May. Optimal temperature for fungal development on wet foliage is 77° F. Infection will occur in 48 hours if spores are present. Prolonged wetness can induce extensive infection.
Integrated Pest Management Strategies
1. Select healthy plants. If spruce trees are dropping their needles, avoid using these trees in the landscape.
2. Remove infected needles and branches during dry, sunny weather. Prune out diseased branches and rake up fallen needles. Burn or remove the collected debris. Disinfect pruning tools between cuts by dipping in a 10% chlorine bleach solution. Oil tools when done to inhibit rust.
3. Avoid overhead watering.Water on the foliage can promote infection. Spores require moisture to germinate and infect.
4. Improve air circulation to allow needles to dry more quickly. Maintain open spacing when planting or by mowing grass or brush.
5. Use fungicidal sprays. Severe infections should be sprayed with chlorothalonil (Daconil), thiophanate methyl (Cleary 3336), or copper-containing fungicides registered for use against this disease. Spray when the needles are half-elongated and again when fully elongated. A minimum of two years of treatment is recommended because of the organism's life cycle.
Symptoms and Diagnosis
Infections take place in the spring, and symptoms show up about a year later. Infected 2-year old needles become spotted or mottled, some turning yellow and some developing a purplish brown color in late summer. Browning becomes general in late winter to early spring, and needles are prematurely shed during summer and fall, 12 to 15 months after initial infection. Black fruiting bodies are visible on discolored needles and even some green ones. The spores emerge from the stomates on the needles so appear in rows along the needles. Scattered lower branches are usually affected first and then browning progresses upward. Symptoms may be confused with spider mite damage. In the latter, mites and fine webbing may be visible; the lines of black fruiting bodies on the needles will also be absent.
Life Cycle
Rhizosphaera kalkhoffii overwinters in infected needles on the tree or ground. Spores are released from the infected needles in the spring, during wet weather. Spores are dispersed by splashing and dripping water. They infect newly emerging needles, as well as mature needles. Infection begins in spring, in April or May. Optimal temperature for fungal development on wet foliage is 77° F. Infection will occur in 48 hours if spores are present. Prolonged wetness can induce extensive infection.
Integrated Pest Management Strategies
1. Select healthy plants. If spruce trees are dropping their needles, avoid using these trees in the landscape.
2. Remove infected needles and branches during dry, sunny weather. Prune out diseased branches and rake up fallen needles. Burn or remove the collected debris. Disinfect pruning tools between cuts by dipping in a 10% chlorine bleach solution. Oil tools when done to inhibit rust.
3. Avoid overhead watering.Water on the foliage can promote infection. Spores require moisture to germinate and infect.
4. Improve air circulation to allow needles to dry more quickly. Maintain open spacing when planting or by mowing grass or brush.
5. Use fungicidal sprays. Severe infections should be sprayed with chlorothalonil (Daconil), thiophanate methyl (Cleary 3336), or copper-containing fungicides registered for use against this disease. Spray when the needles are half-elongated and again when fully elongated. A minimum of two years of treatment is recommended because of the organism's life cycle.
0
0
