Study on Biological Aspects and Control Strategies of Pseudasphondylia diospyros(Diptera:Cecidomiidae)

Pseudasphondylia diospyros mainly damages the local variety of Diospyros kaki in Lanxi City of Zhejiang Province,the larvae feed on under barks of new branches,form galls,and heavily reduce the yield of fruits.This cecidomiid has only one generation in Lanxi,overwinter by first instar larvae in shoots.The adults hatch normally in the early of May,the adult population density can be affected by rainfall,the high density occurred in wet year,low density occurrs in dry year especially dry Spring season.The population density is higher in grafting seedling when local variety Dahongshi as cion than any other varieties,and it is higher in Spring shoots than in Summer and Autumn shoots.It is found that there are three parasitoids on the cecidomiids,i.e.Eurytoma nigrita,Eupelmus urozonus and Cerambycobius sp..The control strategy is to spray insecticides when the most cecidomiid adults emerge,combined with quarantine,culture control measures, concordant of biological and chemical control measures.The relations between occurrence and environment effects were also discussed.