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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
A common tuber disease that occurs wherever potatoes are grown. Potato scab symptoms include dark brown, pithy patches that may be raised and “warty.” These lesions can affect just a small portion of the tuber surface, or may completely cover it. Sometimes the ridged portions are in broken concentric rings.
Potato scab is caused by a bacterium-like organism, Streptomyces scabies, that overwinters in soil and fallen leaves. The organism can survive indefinitely in slightly alkaline soils, but is relatively scarce in highly acid soils. It is transmitted to plants by infected seed tubers, wind and water. The organism is also spread in fresh manure, since it can survive passage through the digestive tract of animals. (Learn how to grow organic potatoes here.) S. scabies enters through pores (lenticels) in stems, through wounds and directly through the skin of young tubers. In addition to potatoes, other crops infected include beets, radish, turnip, carrot, rutabaga and parsnips. This should be kept in mind when considering a crop rotation schedule. Note: S. scabies can survive in the soil for many years in the absence of potato.
Treatment The following control measures have all been proven effective against scab in potatoes. However, in most cases a combination of these techniques will be required. Plant certified, disease-free seed potatoes and resistant varieties whenever possible. We suggest using the russet-skinned varieties since they have more resistance to the disease. Rotate root crops by planting in alternate locations to limit the disease.
Potato scab is most prevalent in dry, alkaline soils. Decrease soil pH by adding elemental sulfur. The disease is controlled or greatly suppressed at soil pH levels of 5.2 or lower. Simple and affordable soil test kits are available to check pH often. Tilling in a cover crop — mustard, canola, alfalfa — prior to planting potatoes will help reduce infection. Some growers report success spreading agricultural gypsum prior to planting at a rate of 25 lbs per 2,000 sq ft. This will raise the calcium content of your soil and help build strong cell walls in plants. (Note: S. scabies disrupts the development of cell walls resulting in lesions.)
Adequate irrigation during early tuber development may have a dramatic effect on common scab infection, but you will need to keep the soil damp for 2-6 weeks. This technique is effective because high soil moisture promotes growth of a bacteria that can crowd out S. scabies on the potato surface. Do NOT overwater.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Affecting a wide variety of horticultural and vegetable crops — roses, beans, tobacco, tomatoes, potatoes, cucumbers and peppers — mosaic is a viral diseases found throughout the United States.
Plant viruses can be difficult to detect as symptoms look similar to many nutrient deficiencies and vary depending on the age of the plant when infection occurs. Look for: Yellow, white or green stripes/ streaks/ spots on foliage Wrinkled, curled or small leaves Pronounced yellowing only of veins Stunted growth and reduced yields Infected fruit appears mottled and develops raised “warty” areas Mosaic virus overwinters on perennial weeds and is spread by insects that feed on them. Aphids, leafhoppers, whiteflies and cucumber beetles are common garden pests that can transmit this disease. Soil, seed, starter pots and containers can be infected and pass the virus to the plant. Cuttings or divisions from infected plants will also carry the virus.
Treatment There are no cures for viral diseases such as mosaic once a plant is infected. As a result, every effort should be made to prevent the disease from entering your garden. Fungicides will NOT treat this viral disease. Plant resistant varieties when available or purchase transplants from a reputable source. Do NOT save seed from infected crops. Spot treat with least-toxic, natural pest control products, such as Safer Soap, Bon-Neem and diatomaceous earth, to reduce the number of disease carrying insects.
Harvest-Guard® row cover will help keep insect pests off vulnerable crops/ transplants and should be installed until bloom. Remove all perennial weeds, using least-toxic herbicides, within 100 yards of your garden plot. The virus can be spread through human activity, tools and equipment. Frequently wash your hands and disinfect garden tools, stakes, ties, pots, greenhouse benches, etc. (one part bleach to 4 parts water) to reduce the risk of contamination. Avoid working in the garden during damp conditions (viruses are easily spread when plants are wet).
Avoid using tobacco around susceptible plants. Cigarettes and other tobacco products may be infected and can spread the virus. Remove and destroy all infected plants (see Fall Garden Cleanup). Do NOT compost.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Pathogen-caused leaf spot diseases, particularly those of stone fruit trees and such vegetables as tomatoes, peppers and lettuce are of two types, those caused by bacteria and those caused by fungus. Leaf spotting of either kind is generally similar in appearance and effect. Prevention and treatment of both kinds often involve the same practices.
Symptoms Infected plants have brown or black water-soaked spots on the foliage, sometimes with a yellow halo, usually uniform in size. The spots enlarge and will run together under wet conditions. Under dry conditions the spots have a speckled appearance. As spots become more numerous, entire leaves may yellow, wither and drop. Members of the Prunus family (stone fruits, including cherry, plum, almond, apricot and peach) are particularly susceptible to bacterial leaf spot. The fruit may appear spotted or have sunken brown areas. Bacterial leaf spot will also attack tomato and pepper crops in vegetable gardens.
Fungal leaf spot attacks lettuce and can also occur on brassicas and other vegetables including such as cabbage, cauliflower, Chinese cabbage, broccoli, Brussels sprouts, kohlrabi, kale, turnip and rutabaga. For more on vegetables susceptible to bacterial and fungal leaf spot, go here. Bacterial leaf spot will also infect some annual and perennial flowering plants including geraniums, zinnias, purple cone flowers and black-eyed Susan. Fungal leaf spot will infect aspen and poplar trees. Leaf spot will also cause problems for strawberry plants. Both types of leaf spot are most active when there is plenty of moisture and warm temperatures. During the summer months, especially if plants are watered by overhead sprinklers, sufficient moisture may be present for infection when the bacteria are splashed or blown on to leaves. Wind and rain transmit the bacteria to plants.
This disease overwinters in the soil around infected plants as well as on garden debris and seeds. It will also remain in the twig cankers, leaves, stems and fruit of infected trees. Control When selecting fruit trees, choose resistant varieties if possible. Keep the soil under the tree clean and rake up fallen fruit. Use a thick layer of mulch to cover the soil after you have raked and cleaned it well. Mulch will reduce weeds and prevent the disease pathogen from splashing back up onto the leaves. Prune or stake plants to improve air circulation. Make sure to disinfect your pruning equipment (one part bleach to 4 parts water) after each cut. Leaf spot among vegetables is most often introduced through infected seed or transplants. Make sure your seeds and transplants are from leaf spot-free stock.
There is no cure for plants infected with bacterial leaf spot. Preventive, organic measures include: Spraying with a baking soda solution (a tablespoon of baking soda, 2 1/2 tablespoons of vegetable oil, a teaspoon of liquid soap, not detergent, to one gallon of water), or neem oil (do not use when pollinating insects including bees or other beneficial insects are present). Baking soda may burn some plant leaves. Spray only a few and then check for a reaction before applying applications every two weeks. Apply sulfur sprays or copper-based fungicides weekly at first sign of disease to prevent its spread. These organic fungicides will not kill leaf spot, but prevent the spores from germinating.
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 copper and pyrethrins, Bonide® Garden Dust is a safe, one-step control for many insect attacks and fungal problems. For best results, cover both the tops and undersides of leaves with a thin uniform film or dust. Depending on foliage density, 10 oz will cover 625 sq ft. Repeat applications every 7-10 days, as needed.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
A fungal disease that affects peaches and nectarines, leaf curl (Taphrina deformans) is one of the most common disease problems found in backyard orchards. Symptoms appears in spring as reddish areas on developing leaves. These areas become thick and puckered causing leaves to curl and distort. When severe, leaf curl can substantially reduce fruit production.
Disease fungi overwinter as spores (conidia) underneath bark, around buds and in other protected areas. Early in the growing season, during cool, wet spring weather, the spores infect new leaves as they emerge from the buds. Later, the fungus produces great numbers of new spores which are splashed or blown from tree to tree. Leaf curl is most active at temperatures between 50-70˚F, but can occur at relatively low temperatures. In fact, cool weather is thought to extend the infection period because new leaves are growing slowly. Wet weather is necessary for infection.
Treatment Select resistant varieties whenever possible. Leaf curl can be controlled by applying sulfur or copper-based fungicides that are labeled for use on peaches and nectarines. Spray the entire tree after 90% of the leaves have dropped in the fall and again in the early spring, just before the buds open. For best results, trees should be sprayed to the point of runoff or until they start dripping. Containing copper and pyrethrins, Bonide® Garden Dust is a safe, one-step control for many insect attacks and fungal problems. For best results, cover both the tops and undersides of leaves with a thin uniform film or dust. Depending on foliage density, 10 oz will cover 625 sq ft. Repeat applications every 7-10 days, as needed.
Keep the ground beneath the trees raked up and clean, especially during winter months. Prune and destroy infected plant parts as they appear. If disease problems are severe, maintain tree health and vigor by cutting back more fruit than normal, watering regularly (avoiding wetting the leaves if possible) and apply an organic fertilizers high in nitrogen.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Found on tomato and potato plants, late blight is caused by the fungus Phytophthora infestans and is common throughout the United States. True to its name, the disease occurs later in the growing season with symptoms often not appearing until after blossom.
Late blight first appears on the lower, older leaves as water-soaked, gray-green spots. As the disease matures, these spots darken and a white fungal growth forms on the undersides. Eventually the entire plant will become infected. Crops can be severely damaged. Unlike other fungal diseases, this plant problem does not overwinter in the soil or on garden trash. Instead the spores are introduced by infected tubers, transplants or seeds. Wind will also carry the disease from nearby gardens. Warm temperatures (70-80˚F) and wet, humid conditions promote its rapid spread.
Note: Late Blight was responsible for the Irish potato famine (1845-1849). Treatment Plant resistant cultivars when available. Remove volunteers from the garden prior to planting and space plants far enough apart to allow for plenty of air circulation. Water in the early morning hours, or use soaker hoses, to give plants time to dry out during the day — avoid overhead irrigation. Destroy all tomato and potato debris after harvest (see Fall Garden Cleanup).
If disease symptoms are observed, treat plants with one of the following fungicides: Apply a copper based fungicide (2 oz/ gallon of water) every 7 days or less, following heavy rain or when the amount of disease is increasing rapidly. If possible, time applications so that at least 12 hours of dry weather follows application. Used as a foliar spray, Organocide® Plant Doctor will work its way through the entire plant to prevent fungal problems from occurring and attack existing many problems. Mix 2 tsp/ gallon of water and spray at transplant or when direct seeded crops are at 2-4 true leaf, then at 1-2 week intervals as required to control disease.
Safely treat fungal problems with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis and is approved for organic use. Best of all, SERENADE is completely non-toxic to honey bees and beneficial insects. Monterey® All Natural Disease Control is a ready-to-use blend of naturally occurring ingredients that control most plant foliar diseases. All stages of the disease is controlled, but applying before infestation gives the best results.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Found on a wide range of plants (too many to mention), gray mold (Botrytis cinerea) is a fungal disease that travels quickly through gardens, especially during damp, cool to mild weather. Disease symptoms appear as grayish colored soft, mushy spots on leaves, stems, flowers and on produce. Spots may become covered with a coating of gray fungus spores, especially if humidity is high. Fruit or plants shrivel and rot and often develop black, stone-like sclerotia — a compact mass of hardened fungal filaments — under rotted parts.
Gray mold is often found near the soil surface or in the densest areas of the plant canopy. It develops on wilted flowers first, then spreads quickly to other parts of the plant. The disease may also occur in storage areas causing rotting of harvested fruits and vegetables. Botrytis blight overwinters on plants, in or on the soil, and as sclerotia. Spores develop when conditions are optimal, and are moved by wind or splashing water onto blossoms or young leaves, where they germinate and enter the plant. Spores require cool temperatures (45-60 F.) and high humidity (93% and above) to germinate. Germinating spores rarely penetrate green, healthy tissue directly, but can enter through wounds on growing plants. Cuttings are particularly susceptible to infection.
Treatment Prune or stake plants to improve air circulation between plants. Make sure to disinfect your pruning equipment (one part bleach to 4 parts water) after each cut. If growing indoors use a small clip-on fan to improve air flow. Keep the soil under plants clean and rake up any fallen debris. Add a good amount of organic compost or mulch under plants. Mulches will prevent the fungal spores from splashing back up onto flowers and leaves. Water in the early morning hours, or use a soaker hose, to give plants time to dry out during the day.
Do not compost infected plant leaves or stems, and thoroughly clean up garden areas in the fall to reduce over wintering sites for the fungal spores. Copper-Soap fungicides will help by protecting plants from disease spores. Apply at the start of flowering and continue every 7-10 days until harvest. Fungicidal sprays are especially warranted when weather forecasts predict a long period of cool, wet weather. Safely treat most fungal diseases, including Botrytis blight, 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. Mycostop, a biological fungicide approved for organic use, has shown suppression of the disease. Direct spray (5 gm/ 50 liters of water) to susceptible leaves, flowers and fruits to point of run-off. Apply every 2-3 weeks, or as needed depending on disease pressure.
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. For best protection, repeat at 1-2 week intervals until conditions are no longer favorable for disease development.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Commonly found throughout the United States, Fusarium wilt is a soil-borne pathogen that attacks potato, tomato, eggplant and pepper plants. Disease fungi (Fusarium oxysporum) enter through the roots and interfere with the water conducting vessels of the plant. As the infection spreads up into the stems and leaves it restricts water flow causing the foliage to wilt and turn yellow.
Disease symptoms often appear later in the growing season and are first noticed on the lower (older) leaves. As the disease progresses, the younger leaves will also be affected and the plant eventually dies. In many cases, only one branch or side of the plant show symptoms. Fusarium wilt can survive for years in the soil and is spread by water, insects and garden equipment. The fungal disease develops during hot weather and is most destructive when soil temperatures approach 80˚F. Dry weather and low soil moisture encourage this plant disease.
Treatment Plant resistant varieties when available. Remove stricken growth from the garden and sterilize pruning clippers (one part bleach to 4 parts water) between cuts. Use Safer® Yard & Garden Insect Killer to control many garden insects, like cucumber beetles, which are known to spread the disease. High nitrogen fertilizers may increase susceptibility to the disease. Test your soil and use a slow-release, organic fertilizer in the vegetable garden. Hand pull or spot treat weeds using a weed flamer or natural herbicide — many weed species host the disease pathogen.
Mycostop is a biological fungicide that will safely protect crops against wilt caused by Fusarium. Approved for use in organic crop production, it can be applied as a soil spray or drench (1-2 gm/ 100 sq ft) to seedlings, ornamentals and vegetables. Apply sufficient water during application to move Mycostop into the root zone. If the disease persists, it is best to remove the entire plant and solarize* the soil before planting again.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Named for the scorched appearance of infected leaves, fire blight is a destructive bacterial disease (Erwinia amylovora) found on apples, pears and other members of the rose family. The disease enters the tree at the tips of the branches and then travels down the stems causing dieback. It attacks soft new growth first, so you would notice dieback at the top of the plant.
Most infected leaves and branch tips wilt rapidly turn brown or black; the leaves die but do not drop off. Trees will also develop reddish water soaked lesions on the bark. On warm days, these lesions ooze an orange-brown liquid. Fire blight kills blossoms, shoots, limbs and sometimes, the entire tree. The bacteria overwinters in infected bark and is spread by splashing rain, dew, wind and insects. It spreads rapidly in moist, warm weather, especially during bloom.
Treatment Select resistant varieties whenever possible. Avoid heavy pruning or excess applications of nitrogen fertilizer, both of which encourage new growth. Avoid planting close to wild plants of hawthorn, apple or pear. As soon as fire blight is discovered, prune off infected branches 1 foot below the diseased sections and burn them to prevent further infection. Dip pruning shears into a 10% alcohol or bleach solution between each cut to avoid transmitting the disease from one branch to another. Early applications of liquid copper are effective against this plant problem. Mix 0.5 to 2.0 oz per gallon of water and apply at silver tip and bud break — repeat at 3 to 5 day intervals up to petal fall. Use the lower rate if disease pressure is light and the higher rate when conditions favor heavy disease pressure.
Bacterial spread can be reduced by applications of products that contain Streptomyces lydicus as the active ingredient. To obtain best disease control, applications should be made at the start of the bloom period and every five to seven days thereafter. SERENADE Garden is a broad spectrum, preventative bio-fungicide recommended for the control or suppression of many important plant diseases. For best results, treat prior to foliar disease development or at the first sign of infection. Repeat at 7-day intervals or as needed.
The systemic action of Organocide® Plant Doctor moves throughout the entire plant to treat most common disease problems. Mix 2-1/2 to 5 tsp per gallon of water and apply to foliage. Spray to run-off, as required for disease control.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Common on tomato and potato plants, early blight is caused by the fungus Alternaria solani and occurs throughout the United States. Symptoms first appear on the lower, older leaves as small brown spots with concentric rings that form a “bull’s eye” pattern. As the disease matures, it spreads outward on the leaf surface causing it to turn yellow, wither and die. Eventually the stem, fruit and upper portion of the plant will become infected. Crops can be severely damaged.
Early blight overwinters on infected plant tissue and is spread by splashing rain, irrigation, insects and garden tools. The disease is also carried on tomato seeds and in potato tubers. In spite of its name, early blight can occur any time throughout the growing season. High temperatures (80-85˚F.) and wet, humid conditions promote its rapid spread. In many cases, poorly nourished or stressed plants are attacked.
Treatment Prune or stake plants to improve air circulation and reduce fungal problems. Make sure to disinfect your pruning shears (one part bleach to 4 parts water) after each cut. Keep the soil under plants clean and free of garden debris. Add a layer of organic compost to prevent the spores from splashing back up onto vegetation. Drip irrigation and soaker hoses can be used to help keep the foliage dry.
For best control, apply copper-based fungicides early, two weeks before disease normally appears or when weather forecasts predict a long period of wet weather. Alternatively, begin treatment when disease first appears, and repeat every 7-10 days for as long as needed. Containing copper and pyrethrins, Bonide® Garden Dust is a safe, one-step control for many insect attacks and fungal problems. For best results, cover both the tops and undersides of leaves with a thin uniform film or dust. Depending on foliage density, 10 oz will cover 625 sq ft. Repeat applications every 7-10 days, as needed.
SERENADE Garden is a broad spectrum, preventative bio-fungicide recommended for the control or suppression of many important plant diseases. For best results, treat prior to foliar disease development or at the first sign of infection. Repeat at 7-day intervals or as needed. Remove and destroy all garden debris after harvest and practice crop rotation the following year. Burn or bag infected plant parts. Do NOT compost.
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Dummer. ゛☀
2017年09月15日
Dummer. ゛☀
Downy mildew (Plasmopara viticola) affects many plants and appears as yellow to white patches on the upper surfaces of older leaves. On the undersides, these areas are covered with white to grayish, cotton-like fungi. These “downy” masses are most often noticed after rain or heavy dew and disappear soon after sunny weather resumes. As the disease progresses leaves may eventually turn crisp and brown and fall off even though the plant has ample water.
Downy mildew occurs in cool, moist weather usually in early spring or late fall. Spore production is favored by temperatures cooler than 65˚F. and by relative humidities approaching 100%. This disease overwinters on plant debris and in the soil. Fungal spores can be carried by insects, wind, rain or garden tools. Treatment The best way to prevent downy mildew is to avoid the environmental conditions that favor the disease.
Prune or stake plants and remove any weeds to improve air circulation. Water in the early morning hours, or use a soaker hose, to give the plants time to dry out during the day. Keep the ground under infected plants clean during the fall and winter to prevent the disease from spreading. Remove and destroy any plants with serious infection (see Fall Garden Cleanup). Choose resistant varieties whenever possible. Downy mildew is comparatively easy to control on most plants when the foliage and fruit are kept protected by a copper spray. Begin treatments two weeks before disease normally appears or when weather forecasts predict a long period of wet weather. Alternatively, begin treatment when disease first appears, and repeat at 7-10 day intervals for as long as needed.
The systemic action of Organocide® Plant Doctor moves throughout the entire plant to treat common disease problems. Mix 3/4 tsp per gallon of water and apply to foliage. Spray to run-off, as required for disease control.
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