How to prevent and control pests and diseases during soybean cultivation?

I) Control of cyst nematode

1. Strengthen quarantine and protect disease-free areas: it is forbidden to transfer soybean seeds from diseased areas.

2. Agricultural control: implement crop rotation of soybean with gramineous crops or non-host plants such as cotton; where conditions permit, paddy-upland rotation is best, and this is currently the most important and effective measure for controlling this disease. The rotation period must not be less than 3 years; more than 5 years provides disease control.

3. Chemical control. The chemicals include: D-D mixture. Use 30-50 kg per mu, apply in furrows 20 cm deep, build ridges and compact the soil after application, and sow 15-20 days later; 3% carbofuran granules, 5-6 kg per mu, mixed with fertilizer and applied just before sowing, but kept separate from the seeds. 15% aldicarb granules: 1.2-1.5 per mu, applied in furrows about 10 cm or more deep at sowing, sow after shallow soil covering, and do not let the seeds contact the chemical.

II) Control of downy mildew

1. Select and promote disease-resistant varieties. The disease-resistant varieties include: Zaofeng No. 5, Baihuacuo, Jiunong No. 9 and No. 2, Fengshou No. 2, Sui 76-5187, Sui 78-5053, Sui 79-5354, Kangmei No. 1.

2. Chemical control. The effective chemicals include: 65% zineb wettable powder at 500 times dilution; 25% metalaxyl wettable powder at 500-800 times dilution; 50% tuijunte wettable powder at 800 times dilution; 75% chlorothalonil wettable powder at 700-800 times dilution. The spray volume is about 60 kg per mu.