Seasonal Incidence of Bactrocera dorsalis and Its Parasitoids in the Field

The seasonal incidence of Bactrocera dorsalis and its major parasitoids were studied by the field investigation in Tianbao,Zhangzhou Prefecture. The results showed that B. dorsalis occurred from March to November each year in the studied area and the peak population took place from June to September. It was made clear that there were 4 species of parasitoids which parasitized on B. dorsalis, and there was a following phenomenon between population variation of each parasitoid and B. dorsalis. It was indicated that Psyttalia incisi was the predominant species of the 4 parasitoids to control B. dorsalis and its population accounted for 77.6% of the total parasitoids samples in the field,which occurred from May to November and its parasitism ratio reached 11.42%. It was found out that both B. dorsalis and P.incisi had obvious preference for infesting and parasitizing,and the population order of P. incisi observed on host plant species was: guava(Psidium guajava) > carambola > rose apple. It was showed that P.incisi preferred of parasitizing on larvae of B.dorsalis infesting on guava and carambola.