Botrytis cinerea is one of the main diseases of tomato in spring conservation. The disease occurs in both the seedling stage and the adult stage, and can be infested on leaves, stems, flowers and fruits. In the seedling stage, most of the disease starts from the damage of the seedlings (including mechanical injuries, frostbite, etc.) or dead leaves. The diseased part is gray-brown, rotten, and has a dense gray mold layer on the surface.
Infected with adult disease, starting from the tip of the leaf and the edge of the leaf, it develops into a "V" shape inside the leaf. At the beginning, it is a water-stained necrotic spot, light brown, and when the humidity is high, the lesion rapidly develops into an irregular shape, and there are large round and large lesions in the dark and light colors, and the surface is gray mold. During the flowering period, the pathogen invades from the flowerbed or the receptacle of the defeated fruit, and gradually develops the fruit, so that the pedicle of the fruit is water-stained grayish white soft rot and produces a gray mold layer.
When the fruit is inflated, the pathogen is infested along the residual stigma or from the umbilicus. The small black spots at the beginning of the depression gradually develop, enlarge, rot, and produce a gray mold layer, which causes the diseased fruit to fall off. The petiole wound left behind after the old leaves is also susceptible to gray mold.
Botrytis cinerea usually begins to develop in early March. Due to the low temperature in the spring of this year, tomato growth is poor. At this stage, the temperature rises, the plant growth in the shed increases, the rainy weather and the humidity increase. The incidence of tomato gray mold in greenhouses is heavier and has formed a peak incidence. The majority of growers should do a good job in the prevention and control of tomato gray mold.
1. Strengthen field management: scientific and fertilizer management should be carried out to control the flooding of large water in fertilizers. Try to increase the appropriate opening time in the morning and evening, reduce the humidity in the shed; strengthen ventilation, adopt variable temperature management, and carry out ecological prevention and control. On sunny days, when the shed temperature is raised to 30 °C, then the shed ventilation is started, so that the indoor humidity is less than 85%; the morning to noon shed temperature is between 25 °C and 28 °C, and the afternoon shed temperature is maintained at 20 °C ~ 25 °C; When the shed temperature drops to 20 °C, close the tuyere to slow down the nighttime shed temperature; the night shed temperature is maintained at 15 °C ~ 18 °C; the cloudy day should also be short-term ventilation. It is not conducive to the sporulation and germination of Botrytis spores, but is conducive to the conditions of tomato photosynthesis and accumulation of photosynthetic products.
2. Remove diseased fruits, diseased leaves and side branches in time after onset. When removing diseased fruits, diseased leaves and side branches, use scissors to gently cut off the affected parts, put them into plastic bags, and destroy them or bury them deeply. Reduce vibration, prohibit littering, and avoid artificial transmission.
3. Spray (蘸) flower control. At the time of flowering per panicle, 50% of the flavonoids (Huiyou) were added to the anti-fallin or the 2,4-D sneezing anthers by 4,000 times to squirt the whole flower spike. The prevention effect against gray mold is very good. 4. Use the drug at the beginning of the disease. Dust or smoke agent can be used in the rainy days, and 10% of the procymidone can be used to prevent and control the smoke. Available on sunny days: (1) 40% pyrimethanil 1000 times; (2) 50% carbendazim 1500 times; (3) 50% chlorfenapyr 4000 times spray, once every 7 days, even spray 3-4 Times. Because gray mold is easy to produce resistance, pesticides should be used in rotation.
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