Control techniques of Soybean Gray Leaf spot

1. Disease: mainly harms the leaves at the adult stage, and infects seeds, seedlings, stems and pods. Round brown spots appeared on the cotyledons of young seedlings born with diseased grains. Irregular plaques may also be formed in the later stage. When it is wet, the central part of the disease spot on the back of the leaf is full of gray mildew layer, which is the conidia of the pathogen. 2. Prevention and control methods: (1) in the humid and rainy areas at the seedling stage, 50% thiram should be mixed with 0.4 kg per 100 kg of seeds. (2) for the susceptible varieties, the dense growing bean fields should be sprayed at the initial stage or pod and susceptible period to control the disease spots on the grains as far as possible. Commonly used agents are 40% carbendazim glue suspension 100 grams per mu, or 50% methyl topiramate 100 grams, with water 80 kg ~ 100 kg spray. According to the development of the disease, the patients were sprayed 2 ~ 3 times at an interval of 7 ~ 10 days.