What are the control measures for soybean continuous cropping pests and diseases?

The main root pests and diseases of soybean include soybean cyst nematode, root rot, root maggot, black velvety chafer, and cutworm.
Control methods:
1. Agronomic measures:
Do a good job of changing soybean varieties, avoid long-term planting of a single variety, and improve soybean's own disease resistance and insect tolerance. ② Advocate mechanical seed selection to remove diseased seeds, insect-eaten seeds, weed seeds, and impurities, reducing opportunities for pest and disease infestation. Sow at the appropriate time; according to the occurrence of pests and diseases in each area, adopt early sowing or delayed sowing to achieve the purpose of avoiding diseases and insects. Plow and turn the soil early, prepare the land finely, remove diseased residues as much as possible, and reduce the probability of pests overwintering.
2. Chemical control:
For plots with severe cyst nematode and root maggot, use 5% phorate, applied with seed fertilizer at sowing in combination with the "three-ridge cultivation" sowing method; seed coating agents can also be used, coating at a ratio of pesticide to seed of 1:75. 35% mephosfolan and 35% ethoprophos, used as seed dressing at 0.5% of seed weight; among these, the application of 5% phorate can also control seedling-stage pests such as two-striped leaf beetle, thrips, and red spider. The above methods can also be used for soybean black velvety chafer and cutworm. In plots with severe root rot, use 50% carbendazim-thiram mixture as seed dressing at 0.5% of seed weight. In areas where root pests and diseases occur together, mixed seed dressing with insecticides and fungicides can be adopted.
　　
The main pests and diseases during the growing period of continuous cropping soybean include soybean downy mildew, soybean gray leaf spot, and soybean pod borer.
Control measures:
1. Agricultural control:
During the soybean growing period, carry out intertillage well to promote the massive formation of new roots and destroy the living environment of pathogens. Strengthen the forecasting and reporting of pests and diseases during the soybean growing period, accurately and promptly determine the control period, and carry out effective control;
2. Chemical control:
In plots with severe soybean downy mildew, use 50% thiram as seed dressing at 0.5% of seed weight. In the early stage of the disease, spray 75% chlorothalonil wettable powder or 25% metalaxyl wettable powder, 100-125 grams per mu diluted with water for spraying, once every 7-10 days, generally requiring 2 times; for plots where soybean gray leaf spot occurs, spray 50% carbendazim wettable powder; for the control of soybean pod borer, in plots with good canopy closure, use the dichlorvos fumigation method or the 5% phorate broadcast application method. Specific method: make poison sticks from corn stalks, insert 1 row every 6 ridges, insert 1 stick every 6 meters, insert 30 sticks per mu, and the efficacy can be maintained for about 7 days. For broadcast application of phorate, apply to 1 ridge every 6 ridges. In plots with poor canopy closure, pyrethroid pesticide spraying can be used for control; in areas where pests and diseases occur together, insecticides and fungicides can be used in combination.