Botrytis blight Goose Gardens Gardening Supplies

http://plantclinic.cornell.edu/FactSheets/botrytis/botrytis_blight.htm

Botrytis blight or gray mold is a fungus disease which infects a wide array of herbaceous annual and perennial plants. There are several species of the fungus Botrytis which can cause blights; the most common is Botrytis cinerea. Botrytis infections are favored by cool, rainy spring and summer weather usually around 15C (60F). Gray mold can be particularly damaging when rainy, drizzly weather continues over several days.

Symptoms

During wet or humid weather, examine any brown or spotted plant material that develops, and look for masses of silver-gray spores on the dead or dying tissue. These spores are readily liberated, and may appear as a dust coming off of heavily infected plant material. Some species of Botrytis form tiny black resting stuctures called sclerotia that may be evident on dead plant tissue in late summer. Not all species of Botrytis readily form these, so they may not be observed on all plants.

Disease Cycle

On most susceptible plants, new infections may begin in the spring as soon as weather conditions are favorable for disease development. Wet or very humid weather may be highly favorable for the spread of the disease. For some Botrytis spp., sclerotia develop in dead plant tissue and form the overwintering stage of the fungus. Fungal mycelium may also overwinter in woody stem debris. Sclerotia then germinate in the spring, or mycelium grows out of infected debris and conidia (infectious spores) develop. Conidia may be windborne or rainsplashed to cause new infections on susceptible host tissue.

Management Strategies

The best way to manage this disease is by inspection and sanitation. While inspecting plants carry a paper bag for sanitation. Remove faded or blighted flowers, blighted leaves, or entire plants infected at the base and place them in the paper bag so that they may be discarded with the trash or burned. It is best not to do any sanitation when plants are wet with dew or rain since this could spread fungal spores during conditions which favor infection. Likewise avoid overhead watering, syringing, or misting plants especially if Botrytis blight has been troublesome in the past. To promote rapid drying of plants, space them to allow good air circulation.

Remember that this fungus can overwinter as tiny, black sclerotia embedded in dead plant tissue. Therefore, practice sanitation every autumn. Remove plant debris from the garden, cut stalks at or below the ground level, and destroy or discard this plant debris.

Fungicide sprays may also help by protecting plants from infections. Apply these when spring weather is continuously cool and wet or if Botrytis blight has been a problem the previous year. There are many effective fungicides for use against Botrytis spp. in New York State, but products vary greatly depending on the site and type of plant(s) to be treated. Each fungicide is registered for use on different plant(s) or groups of plants so be certain the plant(s) which will be treated are listed on the label. Some fungicides with the active ingredients chlorothalonil, mancozeb, potassium bicarbonate, and thiophante-methyl may be registered to treat some plants in the home landscape. Some of those products are also registered to treat plants in the home orchard or vegetable garden. For information on additional pesticides currently registered to treat Botrytis on specific plants, obtain the latest copy of "Pest Management Around the Home" Part II, Miscellaneous Bulletin S74 (available through Cornell Cooperative Extension). The label also contains information on how to apply the fungicide as well as any precautions so follow the label instructions for all pesticides used.

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Botrytis Blight: Botrytis blight is caused by the fungus Botrytis cinerea and often first appears as small water-soaked lesions on the underside of the leaf. Leaves, stems or flowers appear blighted and turn dark brown to gray, often with a fuzzy coating on the surface.

Prevention and Treatment: Collect and discard all dead and dying plant material. Provide better air circulation, and avoid getting the flowers and foliage wet. Botrytis often follows mite injury, so controlling these pests aids in controlling this disease.

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http://www.optimara.com/doctoroptimara/diagnosis/botrytis.html

f your African Violet displays this symptom, it probably has a case of Botrytis. (Note: Do not confuse the fuzzy gray mold of Botrytis with the light gray powder of Powdery Mildew. The Botrytis fungus has a fuzzy appearance and is typically spotty in distribution over the plant. Powdery Mildew, on the other hand, leaves a fine powder that, in most cases, uniformly covers the affected parts of the plant.)

Other Symptoms

Flowers have white or gray spots on them. When taking note of any white or gray spots on your Violet's flowers, be sure to distinguish those caused by Botrytis from those that are merely genetic traits or debris, such as dust or ash. If they are a genetic trait, the spots will show as part of the plant's pigment. If they are debris of any kind, the spots can simply be flicked off. If they are symptoms of Botrytis, however, the spots appear as a growth on the flowers.

Flowers turn brown or have brown spots on them

Flowers wilt or turn mushy.

Leaves darken. They appear brown or black in color.

Leaves wilt. They may appear translucent brown with a soft, jelly-like consistency.

Plant growth is slow.

Treatment

First, isolate infested plants in order to prevent the Botrytis from spreading. Next, remove all dead or dying tissue from the affected plants. Space plants to increase air circulation. Treat with a fungicide, such as Benomyl or Captan (as directed on label).

Prevention

Always remove spent flowers and leaves as soon as you see them. Maintain good air circulation between your plants, especially where the air is damp and still. Keep your growing area and tools clean. Before repotting, disinfect used pots with a 10 percent bleach solution (1 part bleach to 9 parts water). If Botrytis is a recurring problem, you may want to try placing small containers of sulfur among your plants.

Treatment

Prevention

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Botrytis Blight

Small water-soaked lesions form on damaged petioles and spread to leaf blades. Infected flowers fade prematurely

.Space plants and provide ventilation to avoid excessively high humidity. Remove fading flowers and yellowing leaves. Apply chlorothalonil, fenhexamid, copper sulfate (Phyton 27), or mancozeb to protect healthy tissue.

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Botrytis blight or Gray mold, Botrytis cinerea.

Infected flowers develop tan, papery patches and are often covered with gray, fuzzy masses. Senescing flowers are particularly susceptible. Tan to brown spots with a target-like appearance can also develop on the leaves. These patches are often associated with flowers which have dropped onto the leaf surface.

Good sanitation practices including grooming the plants and removing spent or senescing flowers can minimize the potential for infection. These affected tissues should be carefully removed and discarded when they are dry. It is also important to avoid wetting the flowers when watering and crowding plants. Adequate spacing between the plants can promote good air circulation. Control can also be achieved with the use of fungicide sprays applied as soon as symptoms are visible. Among the compounds registered for use in Connecticut are copper sulphate pentahydrate, mancozeb, and thiophanate-methyl. Consult the label for dosage rates, safety precautions, and indoor use.