Studies On Ecology And Control Strategy Of Bradysia Odoriphaga Yang Et Zhang

The study on the occurrence regularity and chemical control of Bradysia odoriphaga Yang et Zhang in main vegetables production in Shanghai area. The results showed that:1. Bradysia odoriphaga Yang et Zhang could occur the seedling of cucumber and watermelon, and it could occur the year round in greenhouse, and the damage in period of seedling was more serious.2. Bradysia odoriphaga Yang et Zhang could occur in open field it started harming vegetables in April and came into hibernation in December. Both spring and autumn were the peak period of the damage by it and the damage in autumn was more serious.3. Artificial feeding the larvae of Bradysia odoriphaga Yang et Zhang with cucumber,carrot agar culture medium(inoculating the Phytophthora infestans) and the carrot agar culture medium(adding the antiseptic) under the condition of 23℃,80%RH. Through comparing,these three kinds of methods each have their pluses and minuse.The first kind of method can offer larvae and adult while making pesticide experiment, the last two kinds of methods are easy to observe the biological behaviour of larvae.4. The appropriate time of controlling Bradysia odoriphaga with insecticides was respectively its adult stage. Such insecticides as beta-cypermethrin, phoxim and azadirachtin had comparatively good effects on controlling its adults. The LT₅₀ values at one day after applying these 3 insecticides of commonly used concentration were respectively 20.13 min, 27.21 min and 57.68 min, and the LT₅₀ at three days after applying these insecticides was respectively 66.61 min, 54.49 min and 104.05 min.5. The another appropriate time of controlling Bradysia odoriphaga with insecticides was respectively its young larval stage. Such insecticides as dichlubenzuron, imidacloprid, cyromazine and phoxim had comparatively good effects on controlling its larvae. The LC₅₀ values of these four insecticides were 39.62 mg/L, 110.67 mg/L, 6.46 mg/L and 378.30mg/L, respectively, and the field control efficiencies at 14 days after applying these four insecticides were all above 80%.6. Several well control measures including yellowboard ensnaring and spraying insecticides on Bradysia odoriphaga adult in the field, and irrigating insecticides on Bradysia odoriphaga larvae in the field were carried out.