Peanut root-knot nematode disease is a devastating disease of peanuts, and it is widely distributed and harmful. (I) Symptoms Root-knot nematode disease mainly infects peanut roots, followed by infestation of peanuts, pods, and fruit pods. Invading from the roots, the root-transporting tissue is destroyed, affecting the normal absorption and operation of water and nutrients. The affected area expands to form a spindle-like, moth-eaten, initially milky white, and later light yellow to dark brown, giving rise to a number of unregulated hair roots on the gall. The nematode invades again and forms a moth. After repeated infections, the entire root system of peanuts has become a messy hair-like “muscle rootâ€. Infected pods form a sore brown husk on the shell, which is called worms. Identification should pay attention to the difference between insects and root nodules, insects more than long at the root end, rough surface, irregular shape, and long hair roots, cross-sectional visible milky sand-grained female; root nodules grow in the root side, round Shaped or oval, smooth surface, no hair roots, cross-sectional visible red or dark green rhizobium liquid bacteria. After being killed, the leaves of the plants yellow and thin, the flowering is reduced, the growth is weak, the plants are short, and the fallen leaves are early. (b) Incidence conditions 1. Soil temperature. When the soil temperature was 11-12°C, the eggs began to hatch, and the larvae broke out at 15°C. The minimum soil temperature for the larvae to infect the root system was 11.3°C, the highest was 34°C, and the most suitable was 15-20°C. When the soil temperature is between 12 and 19°C, the larvae invade takes about 10 days; at 20 to 26°C, it can invade in large quantities within 4 to 5 days; and above 26°C, it is not conducive to invasion. The optimum growth and development of larvae is 25-28°C, and the highest lethal temperature is 45°C. 2 soil moisture. The optimum soil moisture content of larvae invasion is 70%, soil moisture content less than 20% or 90% of the maximum water capacity in the field are not conducive to nematode intrusion. 3. Soil properties. Sandy soil, sandy loam soil, and soil with good permeability and loose texture are heavy; soil with low enthalpy, viscosity, and poor air permeability is light. 4. Cultivation measures. Early sowing peanuts are more severe than late sowing. Continuous crop rotation was more severe than the new peanut area. (C) Control measures 1. Strictly quarantine the old groundnut area peanut root knot nematode is a quarantine object. When planting in different places, we must do a good job of seed quarantine. At the same time, the root-knot nematode has a wide host range, and the quarantine system must be strictly enforced when transporting other host crops. 2. Clean up the pasture and eliminate the source of the disease. After the harvested peanuts were harvested, they were not taken out of the field. The sick and dry bodies were dried in place and burned. When harvesting peanuts, it is necessary to dig deep and carefully, so that the root cause and disease will not be left in the soil. At the same time, weeds were removed from the roots of the weeds and burned. In addition, the diseased body can be used to feed fertilizer and livestock to prevent root-knot nematodes from mixing with manure and spread the hazards. 3. Reasonable rotation. Gramineous crops are not the host crops of root-knot nematodes. Therefore, diseased crops can rotate with crops such as wheat, corn and millet, which can significantly reduce the density of insect populations in the soil. The longer the period of rotation, the smaller the population density. 4. Strengthen field management. Reasonable fertilization, application of organic fertilizer, deep turning and soil improvement, reasonable irrigation, and precision farming can all reduce the risk of root-knot nematode disease. 5. Chemical control. When peanuts are sown, they use 2.5 to 3.0 kg of prophylactic agent per mu, or 1 to 1.5 kg of aldicarb granules, or 3% of carbofuran granules 1.0 to 2. 9 kilograms, mixed with appropriate amount of sand, applied in the sowing ditch, can also be used with 20% of musei granules 1.5 to 2.0 kilograms, furrows or hole application, but can not be in direct contact with the seeds. 5% aldicarb has 1 kg of 10% grams of phosphor particles per acre. In addition, Kedandan, Keke phosphorus, and DD mixtures have certain control effects on root knot nematodes.