Detailed Explanation of Key Technical Points for Soybean Viral Disease Control
Soybean is what is called yellow bean in the south. Soybean is extremely prone to viral diseases, and there are many types, about a dozen or so viral diseases. Viral diseases are mainly spread by insects, and seeds can also carry viruses. Several viral diseases in the south are spread by aphids. Sometimes several viral diseases occur together. What do the symptoms look like, and how should they be treated? Let us study together.
1. Causes of the disease
There are three pathogens in total. One is soybean mosaic virus, which causes mosaic symptoms; cucumber mosaic virus, which causes stunting and ring patterns on seeds; and alfalfa mosaic virus, which causes yellow mottling. These viruses can occur at the same time, producing mixed symptoms. These viruses mainly occur in the south. They rarely occur in the north.
2. Disease manifestations
When the disease occurs in spring, the upper leaves become mottled, lose chlorophyll and turn yellow, with mosaic patterns, and the leaf mesophyll has blister-like raised areas. They gradually begin to wrinkle. After the leaves become deformed, the edges curl downward. The whole plant begins to become shorter, and few pods are set; even when pods are set, they are deformed pods. After maturity, the seeds in the pods are very small, and brown spots may also appear inside.
3. Disease triggers
=Some high-yielding varieties are more susceptible to the disease than short, sturdy disease-resistant varieties. In regions or seasons with drought and little rain, there are many insects, especially large numbers of reproducing aphids, so the disease becomes very severe. Plants with weak growth due to nutrient deficiency are easily infected.
4. Control methods
It is better to choose disease-resistant varieties such as Liaoxian No. 1. Plants kept for seed should be planted separately, and disinfection should be done carefully from seeds to soil. Fertilizer should be applied at every stage to maintain soil nutrient supply. Pay attention to controlling aphids; do not let aphids cause damage everywhere and prevent them from spreading. Use a 500-fold dilution of 20% Virus A for spraying, or spray a 1000-fold dilution of 1.5% Zhibingling emulsifiable concentrate. For aphids, spray a 500-fold solution of 10% imidacloprid.
The common viral diseases of soybean are the above three, mainly causing damage in the south. Aphids are the main transmission vector. Aphid control must be emphasized in order to effectively control the disease. Viral disease control should use pesticides when the disease is mild.