![]() This air exchange should only take 5 or 10 minutes. Even if the incoming air is saturated, the RH will drop significantly as the air warms. The warm humid air is ventilated to the outside as the cooler outside air is drawn into the greenhouse. To prevent excessive humidity and dew formation, turn on the heat and open the vents. ![]() This film of moisture is essential for Botrytis (and other fungal pathogens) to germinate and cause infection. In the evening, as warm air becomes cooler, the relative humidity (RH) rises until water vapor begins to form a film of moisture on surfaces (dew formation). Warm air holds considerably more moisture than cool air. Reduction of humidity by heating and ventilating is relatively inexpensive compared to the loss of revenue that can result from Botrytis blight and other plant diseases. Environmental regulation (temperature, relative humidity, leaf wetness duration) is critical. Manage insect pests, which may carry spores between plants and cause injuries that enable fungal infection. Avoid overfertilization, which leads to overproduction of succulent tissues. Space plants properly to allow for good air circulation, which reduces both leaf wetness duration and the relative humidity within the canopy. ![]() Remove plant debris from the greenhouse completely do not place it in garbage cans. Control weeds and remove plant debris between crop cycles and during production. Cultural ManagementĪn integrated program including good sanitation practices, monitoring, environmental control, and fungicides is required for the successful management of Botrytis blight. Given the common occurrence of Botrytis in greenhouses and the relative ease with which it spreads, greenhouse managers must avoid conditions that are conducive to disease development. The fungus may also produce chlamydospores and/or microsclerotia, both of which can survive in soil for extended periods of time. Spores are easily disseminated by air currents and splashing water. Botrytis blight is more prevalent in the spring and fall months. Colonization of plant tissue takes place at a wide range of temperatures, but 60-75☏ is optimum. Germination of spores and infection of the host is dependent on a film of moisture for 8 to 12 hours, relative humidity 85% or greater, and temperatures 55 - 75☏. Like other fungi, Botrytis has a specific range of temperature and relative humidity that is necessary for spore germination, infection, and disease development. Copious spores are produced on lesions as well as on plant debris left on benches, the greenhouse floor, and cull piles. The fuzzy spore masses may be visible to the naked eye or observed with a hand lens. Spores may be whitish in appearance but turn gray as they mature. Leaf lesions may begin as brown, water-soaked areas. Plants may be attacked at any stage but tender new growth, freshly injured tissues, and aging or senescent tissues are preferred. Signs and Symptomsĭepending on the host and environmental conditions, Botrytis can cause leaf and flower blight, fruit rot, cankers, damping off, and root rot. ![]() A sound IPM program including is necessary to control this disease. A wide variety of plants including ornamentals, vegetables, and herbs are susceptible. Botrytis blight is most often caused by Botrytis cinerea, but other species may also be problematic. The disease is often referred to as gray mold because it produces abundant fuzzy gray spores on the surfaces of infected tissues. This level of control was not significantly different from control achieved by the fungicide iprodione (74%).Botrytis blight (“moho gris” or “pudrición gris” in Spanish) is one of the most common fungal diseases of greenhouse crops. jeanselmei, which reduced the number of lesions by 63%. The most effective antagonist was a yeast, E. Biological control by these antagonists, Exophiala jeanselmei, Cryptococcus albidus, an Erwinia sp., and a coryneform bacterium, was demonstrated by applying them to cut roses 1 day before inoculation with a suspension of 1,000 conidia of B. Preliminary evaluations identified four microorganisms with the ability to reduce the number of lesions caused by Botrytis cinerea on rose. DOI: 10.1094/PD-71-0799.įungi and bacteria isolated from rose petals were evaluated for their potential as biological control agents of Botrytis blight, a serious disease of greenhouse-grown roses. Copyright 1987 The American Phytopathological Society. Department of Plant Pathology, University of California, Davis 95616. ![]() Redmond, Department of Plant Pathology, University of California, Davis 95616. Biological Control of Botrytis cinerea on Roses with Epiphytic Microorganisms. ![]()
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