How to prevent diseases and insect pests of Chinese yam

First, anthrax. Chinese yam is easy to produce anthracnose in high temperature and rainy season, resulting in withered stems and fallen leaves. In the early stage, there were black spots on the leaves, but in the later stage, the color of the leaves changed to black, and the disease spots were flooded, which seriously affected the plant growth and reduced the yield. Prevention and treatment: spray 50% methamphetamine 600x solution or 1000 times methyl topiramate every 7 days for 3 times; remove diseased leaves in the field in time and remove stagnant water. Second, brown spot. It mainly harms the leaves and is serious in the rainy season. Yellow or yellow-white disease spots appeared on the leaves at the initial stage of the disease, but the color of the leaves changed to light brown in the later stage, and withered in severe cases. Prevention and treatment: at the initial stage of the disease, 50% of thiophanate solution or 1000 times of methyl topiramate was sprayed every 7 days. It can also be prevented with 2.5% of the enemy killing 2000 times the liquid. Third, mosaic disease. Most of the veins showed green belts. When the leaves were fully unfolded, there were chlorotic spots and wheel lines on the leaves, and necrotic spots appeared on the leaves in the middle and later stages of growth. Prevention and treatment: choose healthy root tuber as seed. To control aphids, 10% imidacloprid wettable powder 1000 times, or 25% aphid lice EC 3000 times, 10% aphid lice kill 1000 times alternating spray. Fourth, nematode disease. Most of them occurred in the high temperature season in early autumn, with irregular brown spots on the underground roots and oval spots on the aboveground stems. Prevention and treatment: choose healthy root tuber as seed. If there is still suspicion of infection, soak the seeds in warm soup, that is, soak the seeds in warm water of 52-54 ℃ for 10 minutes and stir them up and down twice to make them heated evenly to achieve the purpose of killing insects. The seeds can also be soaked in 40% methyl isofloxate 500 times 800 times solution for 48 hours, dried and then dried. Fifth, the small land tiger. During the growing period, the tuber was bitten, so that the tuber could not grow normally, which seriously affected the yield and quality of yam. Prevention and control: 40% phoxim granules can be sprinkled into the field before transplanting, or irrigated with 90% crystal trichlorfon 1000 times 500 times, or 2.5% trichlorfon 2000 times solution for control. Grubs. During the growing period, the tuber was bitten, so that the tuber could not grow normally, which seriously affected the yield and quality of yam. Prevention and control: 60-80 paulownia leaves are placed every 667 square meters in the evening, and the paulownia leaves are face down, and manual hunting is carried out in the next morning. You can also use 90% crystal trichlorfon 50 grams per 667 square meters, add 1.5 kilograms of water to dissolve and mix 1.5 kilograms of fried cottonseed cake to make poison bait. In the evening, the poison bait is scattered among the rows to trap and kill the larvae. 40% phoxim granules can also be sprinkled into the field before transplanting yam, or irrigated with 90% crystal trichlorfon 1000-1500 times.