[1] Main occurrence area. Citrus yajian silkworm mainly occurs in Jiangsu, Zhejiang, Fujian, Hunan, Hubei, Henan, Hebei, Shaanxi, Jiangxi, Guangdong, Guangxi, Sichuan, Yunnan, Anhui and other places.
[2] Main harmful parts and symptoms. Citrus yamosaurus is dominated by nymphs and female adults that harm the sap of citrus leaves, fruits and twigs. The less affected leaves are often yellow spots, if many nymphs gather, the reverse side of the victim is a large yellow spot, and in severe cases, the leaves will bend and deform, and the branches and leaves will die. The affected fruit is often yellow-green, ugly in appearance, and sour in taste, which seriously affects the quality and yield of citrus.
[3] The period of occurrence of major hazards. Citrus yapids, can occur 2 to 4 generations a year, with female adults and 2-year-old nymphs overwintering, in April to May of the second year, when the average daily temperature reaches more than 19 degrees, the overwintering female adults begin to lay eggs and hatch, and the generations overlap, until the average daily temperature reaches less than 17 degrees in October, and stop laying eggs. The warm and humid climate is conducive to the occurrence of insect pests, and the high mortality rate of high temperature and drought larvae is high, and it is conducive to the occurrence of insect pests in places with closed tree canopy.
[4] Prevention and control measures.
1, 25 days after the first flowering and when the first generation of two-instar males begin to appear, 5 days later is the first control period. Spray the drug again after 20 days. Spray control should be carried out when the overwintering female adults reach 10% of the leaves in the autumn shoots last year, or when there are more than two small shoot groups on the trees with obvious insects or a few branches and leaves are scorched, or when the overwintering female adults on the leaves of the autumn shoots reached 15 heads per 100 leaves last year.
2, prevention and treatment of drugs. You can use Emilion 1500 times liquid, 40%, quick culling 1000 times liquid or 99% lu ying 200 to 300 times. Remove diseased insect branches and pants and some corn juice to reduce members and ventilate light to protect natural enemies, especially the Japanese square head beetle, Hubei red-spotted lip ladybird, arrow-tip aphid wasp and flower horn aphid wasp.
