Common soybean diseases and how to prevent and control them
What diseases need to be prevented and controlled when growing soybeans? Here is an introduction. The diseases that need to be prevented and controlled when growing soybeans are: 1. Soybean root rot: This disease can occur and cause damage throughout the entire growth period of soybeans, reducing yields by 25-75% or more. The protein content of affected seeds is significantly reduced. The main symptom is the appearance of dark brown...
What diseases need to be prevented and controlled when growing soybeans? Here is an introduction
The diseases that need to be prevented and controlled when growing soybeans are:
1. Soybean root rot: This disease can occur and cause damage throughout the entire growth period of soybeans, reducing yields by 25-75% or more. The protein content of affected seeds is significantly reduced. The main symptom is the appearance of dark brown lesions at the base of the stem, which spread upward to varying degrees to the lower lateral branches, causing the pith of the diseased stem to turn brown, the base of the petiole to constrict, and the leaves to droop but not fall off. For chemical control, mainly use 58% ridomil mancozeb or 72% curzate wettable powder, both at 0.3-0.4% of seed weight for seed dressing.
2. Soybean sclerotinia rot: Soybean sclerotinia rot mainly infects the stems, with symptoms beginning in late July. In the early stage of infection, brown lesions appear on the stems, and later white cottony mycelium and white granules appear on the lesions, which then turn into black granules (sclerotia). When the stem of a diseased plant is cut lengthwise, black cylindrical sclerotia resembling mouse droppings can be seen, and the dead plant turns grayish white. For chemical control, spray with 50% procymidone wettable powder at 1000 times dilution, or 40% sclerotia net at 1000 times dilution, or 50% thiophanate-methyl at 500 times dilution.
3. Soybean frogeye leaf spot: Also known as spot disease, it generally begins to appear on leaves in early to mid-June and enters its peak period in mid-July. Pods become affected starting from the tender pod stage, with the seed-filling stage being the peak period. In years with high temperature and frequent rain in July-August, the disease is severe. It mainly damages leaves. When severely affected, almost all leaves are covered with lesions, causing premature leaf drop, reducing yields by 20-30%, and also decreasing 100-seed weight and lowering quality. Chemical control: In addition to seed dressing at sowing with 70% dexon wettable powder or 50% thiram wettable powder at 0.3% of seed weight, during the flowering and podding stage of soybeans, use 1.5 kg of 40% carbendazim suspension concentrate per hectare, diluted in 450 kg of water for spraying.
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