Sweet potato stem nematode disease is the enemy of sweet potato production. Sweet potatoes infected with stem nematode disease, cracking the vetch epidermis, the formation of irregular brown spots, pith intramedullary part into a dark brown, was dry when severe. The black spots of the potato chips appear on the epidermis, and larger cracks form. The inside of the potato pieces turns black and rot, commonly known as heart disease. The head of the sweet potato stem nematode has iron nail-like needles. It penetrates the root tissue of the sweet potato with a needle, drills inside the potato block, and feeds nutrients to make the internal tissue of the potato gray and brown. The incidence of light sweet potato stem nematode disease was reduced by 20% to 30%, and severe cases reduced production by more than 50% or even lost. To control sweet potato stem nematodiasis, we must first select the varieties that have strong resistance to disease and can obtain higher yield before nursery. The most ideal varieties are Guangshu 92-66. Secondly, it was applied twice at the seedbed stage: the first time after inserting the potato seeds, and the second time after pulling out the second pod of yam, 5% of Aldicarb Granules were used at 40 to 50 grams per square meter. After mixing with fine soil, spread it to the seedbed evenly, spray water after applying the pesticide, and control the disease-free seedlings for the overwintering stem nematodes in the soil. Swelling in the whole spring potato field, insert the seedlings into the ridge, and water the holes in the seedlings. Use 22.5 to 30 kilograms of sweet potato stem threads per mu or 30 to 45 kilograms of halvacarb. Sprinkle into the seedling hole, watering the soil, can effectively control the sweet potato stem nematode disease. Prevention of sweet potato stem nematode disease can also take a turn for cropping methods, severe disease fields can be changed to peanuts, rice and other crops, and the use of clean manure, the best 3 to 4 years after the planting of sweet potatoes, so better disease prevention.
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