Control measures of diseases and insect pests in soybean continuous cropping

Soybean root diseases and insect pests are mainly cyst nematode disease, root rot disease, root miner, black velvet beetle, ground tiger. Control methods: 1. Agronomic measures: do a good job in the replacement of soybean varieties, avoid planting a single variety for a long time, and improve the disease resistance and insect tolerance of soybean itself. ② advocates mechanized seed selection to remove diseased grains, insect-eating grains, weed seeds and impurities, and reduce the chance of disease and insect infestation. Sowing at the right time, according to the occurrence of diseases and insect pests in various places, and adopt the method of early sowing or delayed sowing to achieve the purpose of avoiding diseases and pests. Ploughing as early as possible, fine soil preparation, as far as possible to remove the disease and debris, reduce the probability of pests overwintering. 2. Chemical control: 5% methyl mixed with phosphorus on the land with heavy cyst nematode and root maggot, along with the sowing method of "three-ridge cultivation", and seed coating agent can also be used to coat the land according to the proportion of medicine: species at 1:75. 35% methyl thiocarbophos and 35% ethyl thiocarbophos are mixed with seeds according to 0.5% seed amount, in which 5% methamidophos can also be used to control two leaf beetles, thrips, red spiders and other seedling pests. Soybean black velvet beetle shell and ground tiger can also apply the above methods. In the land with severe root rot, collect 50% Duofu mixture and mix seeds according to 0.5% of the seed amount. In the mixed area of root diseases and insect pests, mixed seed dressing with insecticides and fungicides can be adopted. The main diseases and insect pests during the growth period of soybean continuous cropping are soybean downy mildew, soybean gray spot and soybean heart borer. Prevention and control measures: 1. Agricultural control: do a good job of mid-tillage during the growth period of soybean, promote the formation of a large number of new roots, and destroy the living environment of pathogens. Strengthen the prediction and forecast of soybean diseases and insect pests during the growth period, determine the prevention and control period accurately and timely, and carry out effective control; 2, chemical control: in the land with serious soybean downy mildew, 50% Fumishuang is used to mix seeds at 0.5% of the seed amount. At the initial stage of the disease, 75% chlorothalonil wettable powder or 25% Ruidu wettable powder can be sprayed with 100-125g / mu of water, once per 7-lO day, usually twice; soybean gray spot occurrence plots are sprayed with 50% carbendazim wettable powder; soybean heart borer is controlled by dichlorvos fumigation or 5% methyl mixed phosphorus removal method in the land with good ridges. Specific methods: make poison sticks with corn stalks, insert 1 row every 6 rows, 1 branch per 6 meters, 30 sticks per mu, and the efficacy can be maintained for about 7 days. One ridge of phorate was removed every 6 ridges. In the land with poor ridge sealing, pyrethroid pesticide spraying can be used, and insecticides and fungicides can be used in mixed areas of diseases and insect pests.