Chestnuts and red spiders are called coniferous claws, which damage the leaves of the chestnuts and cause the leaves to fade into yellow-white spots. When they are severe, the leaves are brown and brown, resulting in reduced yields. The wintering of the ovum in the leaves of the 1-4 years old leaves, rough slits and branches over the winter, from the end of April to the beginning of May the following year, hatching, when the chestnut buds germinating period, in mid-May cub crawling On the damage of new leaves, red spiders occur 4-9 generations a year. The second to fifth generations of the flood season are the heaviest. The time is generally between June and July. The suitable temperature is 24-25 degrees Celsius. Earlier and heavier, Yangpu chestnut occurred earlier and heavier than the shady chestnut garden.
Control methods: In May, scrape the 5â€“10 cm circumference of the rough skin. Apply 40% omethoate EC 2 to 5 times to the exposed trunk to coat the trunk. Then use a plastic film to wrap it. It can also be sprayed with 20% amitraz EC 2000 times or 20% diclofen EC 1000 times from late May to late June.