Pest Control Marketing

Prabhdee says:

FUNGAL DISEASES
Fungal diseases are the most common type of disease in vegetables. Fungi don’t contain chlorophyll and can’t produce their own food using photosynthesis, so they get their nutrients from other living things. Fungi are made up narrow web-like strands called hyphae, which release enzymes and absorb food. Most fungi feed on dead and decaying matter, and are beneficial to gardeners as they aid in the decomposition of matter, returning minerals and nutrients to the soil. Some fungal infections are actually a good thing – mycorrhizal fungi infect the roots of many plants, forming a symbiotic relationship with the plant that actually helps the plant absorb nutrients – especially phosphorus – and withstand drought.
Some fungi are destructive in the garden, however. Common fungal diseases in plants include blights, botrytis, clubroot, damping off, leaf and pod spots, mildews, and wilts.
Blights thrive in warm, wet weather and may affect vegetable crops such as potatoes and tomatoes. Potato blight was the cause of the Irish Potato Famine in the 1840s. Blight starts with dark spots which progress to wilting, yellowing leaves, and rotting fruit. If blight occurs, destroy diseased foliage and dispose of any infected potatoes, as the disease can overwinter on diseased tubers. Buy certified seed potatoes, which are free of disease. Practice crop rotation with vegetables.
Botrytis (grey mould) is a common vegetable disease that affects plants such as lettuces and tomatoes. Botrytis likes cold, damp conditions. Brown-spotted or blotchy leaves are an early sign, followed by a fluffy grey mould that causes the plant tissue underneath to die. As with other fungal diseases, prevent botrytis by keeping plant foliage dry, clearing the vegetable garden of debris at the end of the gardening season, and destroying affected plant matter.
Clubroot is a fungal disease that attacks brassicas such as broccoli, cauliflower, and cabbage. Once clubroot is in the soil it can remain there for up to 20 years. Prevention is the best way to deal with clubroot. Grow your own plants from seed, or be sure to buy seedlings from a reputable grower. Clubroot can only survive in acid soil, so if the soil is already infected, raise the pH above 7.2 to eradicate the disease.
Damping off is a fungal disease that can affect any type of vegetable plant, and is caused by several different types of soil- or water-borne fungi. Affected seedlings collapse and die, or they may not emerge at all. Infected containers, overcrowding, and poor ventilation are frequent causes of damping off. Clean and sterilize pots and flats, don’t sow seeds too thickly, and don’t over water.
Leaf and pod spots (anthracnose) can occur on beans, as well as vegetables like brassicas, cucumbers, peppers, and tomatoes, creating sunken brownish spots. Remove and dispose of infected plants. Buy disease-resistant seed varieties.
Downy mildew results in yellowing leaves with a greyish or white mould on their underside. Older leaves have tiny black fungi spots on their leaves, and slowly die in the autumn. Wet foliage can cause fungal diseases such as downy mildew. Don’t water with a sprinkler – use drip irrigation or container watering. Susceptible plants include lettuce, onions, peas, and spinach. Powdery mildew occurs in hot, dry conditions when plants are overcrowded. Use sufficient water to prevent powdery mildew and destroy affected leaves to keep it from spreading.
Fusarium wilt and verticillium wilt are fungal diseases that cause leaves to turn yellow and look wilted. The yellow leaves turn brown and the disease usually starts from the bottom of the plant and works its way up, eventually killing the plant. Fusarium wilt is the most common form of the fungal disease, and is more prevalent in warm climates. Verticillium wilt is more common in cooler regions. Both fusarium wilt and verticillium wilt can be spread by cucumber beetles and squash vine borers. Crop rotation may have little effect on fusarium and verticillium fungi, which can survive in the soil for several years without a host plant. Grow disease-resistant varieties and destroy infected plant material, disposing of it properly.
VEGETABLE DISEASES AND THEIR CONTROL
Damping-Off (seedling disease)—Seeds of many vegetables are susceptible to damping-off fungi when planted in infested soils. The seeds may fail to germinate, or seedlings may be attacked before or after emergence and turn brown, shrink, and finally die. Control measures include these: plant fungicide-treated seeds in well-drained areas; do not apply excessive amounts of nitrate forms of nitrogen fertilizers; and rotate the location of the vegetables.
Root Rot of Beans and Southern Peas—Root rot is severe on green beans, lima beans, and southern peas. The disease first appears as reddish or reddish-brown areas on stems and roots. As the disease advances, discolored areas spread until the entire root and lower stem are affected. Above-ground symptoms include stunting, yellowing, drooping of leaves, failure to produce normal pods, and death.
These control practices reduce losses from root rot:
* Use high-quality seeds treated with a fungicide like Arasan.
* In-furrow fungicides (Terraclor) help control root rot. Apply one-fourth of the material in the open furrow and the remainder in the covering soil during planting.
* During cultivation, do not throw soil against plant stems.
* Plant in a 4- or 5-year rotation with other vegetables.
* Plant in well-prepared soils with a pH of about 6.5, fertilized according to a soil test and treated for nematodes if recommended. Plant seeds 1 inch deep only during favorable weather, in warm soils, and on top of a bed to avoid “drowning.
Early Blight of Tomatoes—Early blight is a major disease of tomatoes in Mississippi. Symptoms first appear on lower, older leaves as circular, dark brown to black spots that often contain rings, giving a “target board” effect. As the disease progresses, leaves turn yellow, wither, and drop off. Frequently, only the upper half of the plant has green leaves, and in severe cases, the plant becomes completely defoliated.
Early blight also occurs on plant stems and sometimes on fruit. On seedlings, the disease may girdle the stem and give the appearance of damping-off.
Reduce losses to early blight by providing good ventilation in plant beds and watering when leaves have time to dry. Seed treatment with Thiram aids in controlling the damping-off stage. Do not set tomato plants where early blight occurred the year before, and remove and destroy all diseased plant debris in the garden after harvest.
Applications of chlorothalonil or mancozeb effectively control this disease. There is no waiting period after application until harvest for Bordeaux mixture or chlorothalonil, but there is a 5-day waiting period for mancozeb.
Begin applying when plants are 8 to 10 inches tall, and continue at 7-day intervals through the growing season. Applications of these fungicides also control some of the other leaf, stem, and fruit diseases of tomatoes.
Blossom End Rot – Tomato
Blossom-End Rot of Tomatoes—Blossom-end rot occurs on the tomato fruit. It may also be a problem on peppers, squash, and watermelons. It is more common on fruit that is one-third to one-half grown and occurs on the blossom end of the fruit. It begins as a small, water-soaked spot that develops into a dark brown, leathery spot that may involve half the fruit. The surface of the spot shrinks and becomes flat or sunken.
Blossom-end rot is caused by a lack of calcium in the developing fruit. The uptake of calcium from the soil by the tomato plant can be reduced by fluctuations in soil moisture—either excessively wet soil or excessively dry soil. The disease commonly occurs when plants are grown rapidly and luxuriantly early in the season and are then subjected to prolonged dry weather. Because of drying conditions, the disease may be more serious on the windward side of a garden and on staked tomatoes than on unstaked or bushy plants.
Prevent blossom-end rot by maintaining a soil pH around 6.5, irrigating and mulching to maintain uniform soil moisture, and avoiding heavy applications of nitrogen. Control blossom-end rot by spraying with 4 tablespoons of 96 percent calcium chloride per gallon of water at 7- to 10-day intervals for 4 applications. Begin spraying with first appearance of symptoms. Overdosing plants with calcium chloride may result in leaf burn. Calcium chloride is suggested only for tomatoes.
Spotted Wilt
Spotted Wilt of Tomatoes and Peppers—This viral disease is transmitted by several species of thrips and may kill plants or drastically reduce fruit-set. Fruits from diseased plants are generally small and distorted. Tomatoes develop irregular yellowish blotches.
Initial symptoms appear as thickening of veins on younger foliage. Younger foliage generally exhibits a pronounced downward curling. Inter-nodes become shortened, and immature fruit does not ripen. Dark purple streaks can occur on leaves, stems, and fruits. Other symptoms are blighting and blackening of young shoots. On individual leaflets, small, dark, circular dead spots may appear. Badly spotted leaves may turn dark and wither.
Some varieties are now being released with resistance. Check with your seed source. It is not clear how effective or long-lived these resistant cultivars will be.
Try these control practices:
* Remove and destroy diseased plants.
* Keep weed populations down in and around gardens to reduce movement of virus-carrying thrips from weeds to garden plants.
* Suppress thrips by applying approved insecticides (Malathion 50 or Diazinon 25 EC at 2 teaspoons per gallon).
* Further suppress thrips with shiny mulch materials around tomatoes and other susceptible vegetables. Apparently,