Sclerotinia sclerotiorum can harm leaves, petioles and stems. The first leaf is usually diseased, with dark stains, and a dense layer of white mold on the surface when wet. Then spread downward causing petiole and stem disease. The affected part was brownish water-stained. When the speed was high, soft rot was formed. White mycelium grew on the surface. Finally, the stalk tissue rotted and hollowed out in the fibrous stem, forming rat urine-like black sclerotia. At present, it has entered the autumn and there is a large temperature difference between day and night, which is conducive to the occurrence of the disease. It must be given high attention so that early detection, early prevention and control, and loss reduction can be achieved.
The onset of ascospore transmission by wind and rain, infestation of old leaves with weak life, sick leaves and robust leaves, stem contact can spread hyphae. High temperature and humidity are conducive to the occurrence and epidemic of the disease. It is easy for celery to connect with fleas or cruciferous vegetables that are prone to sclerotinia. Poor drainage during the rainy season, with a heavy nitrogen fertilizer.
Control methods 1. Agricultural control. Implement more than three years of rotation. Seed disinfection before sowing. During the rainy season, timely drainage will reduce the humidity in the field. The diseased leaves were removed from the fields in a timely manner, concentrated deep, and prevented from spreading. 2. Chemical control. At the beginning of onset, 70% thiophanate-methyl wettable powder 600 times, 50% carbendazim wettable powder 500 times, or 65% triamcinolone wettable powder 1000 times, sprayed 5 to 7 days Continuous control 2 to 3 times. The above pesticides are used alternately to avoid drug resistance.
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