Studies On The Biology And Ecology Of Opius Dimidiatus (Ashmead)

The Liriomyza sativae Blanchard and Liriomyza huidobrensis Blanchard are all the quarantine pest in many countries. And now they have become the important pest on vegetable and ornamental crops in china since the former was firstly found in Hainan province in 1993 and the latter was firstly found in Yunnan province in 1994. The paper studied on the biology and ecology of Opius dimidiatus (Ashmead), which is the important larval-pupa parasitoid wasp of the two species leafminers.The result of research showed that there are 6 parasitoid species in Guizhou province, i.e. Opius dimidiatus (Ashmead), Opius dissitus Muesebeck, Chrysonotomyia okazakii Kamijo, Diglyphus isaea (Walker), Chrysocharis pentheus (Walker) and Hemiptarsenus varicornis (Girault). Among these, Opius dimidiatus (Ashmead) was the dominant species. It is concluded that the parasitoids play a very important role in the natural control of the leafminer.The result is studied on the spatial pattern of the leafminer larval that belong to core pattern.Temperature significantly affected the development of Opius dimidiatus (Ashmead) at range of 15-30 ℃, the developmental period of Opius dimidiatus (Ashmead) was decreased with the temperature increasing. According to the law of effective accumulative temperature ,the low temperature threshold of development for the egg, larval, pupa and egg-pupa of Opius dimidiatus (Ashmead) were estimated to be 9.633 ℃ ,10.943 ℃ ,10.023 ℃ and 10.232 ℃ respectively; the effective accumulative temperature for the egg, larval, pupa and egg-pupa were 53.982, 59.126, 75.433 and 188.62 day-degrees respectively. Both the longevity of adult and generation period decreased with the temperature rising, the relationship between longevity of adult (y) , the mean total number of eggs laid by per female (y) and temperature (x) were described as the following formula: y=—0.9466x + 37.07 (R~2 =0.9875), y=-0.6403x~2+25.661x-166.83(R~2=0.8674).