病原线虫对桔小实蝇种群的控制作用

通过室内和田间实验研究了昆虫病原线虫对桔小实蝇Bactrocera (Bactrocera) dorsalis (Hendel)的控制作用。室内实验结果表明，供试的3种线虫的4个品系（小卷蛾斯氏线虫Steinernema carpocapsae All品系与A24品系，夜蛾斯氏线虫Steinernema feltiae SN品系和嗜菌异小杆线虫Heterorhabditis bacteriophora H06品系），以小卷蛾斯氏线虫All品系对桔小实蝇的侵染力最强，其3天的LD₅₀和LD₉₅分别为35.0和257.1条/cm²土壤。按300条/cm²土壤的量施用，小卷蛾斯氏线虫All品系对当代桔小实蝇的控制效果为86.3%。用以虫期作用因子组建的生命表方法评价了小卷蛾斯氏线虫All品系对田间桔小实蝇下代种群的控制作用，结果表明，按300条/cm²土壤的量施用线虫，对照杨桃园的桔小实蝇种群趋势指数为105.9，而处理杨桃园的桔小实蝇种群趋势指数下降为15.5；小卷蛾斯氏线虫All品系对桔小实蝇的干扰控制指数为0.146，即线虫处理果园的下代种群密度仅为对照果园的14.6%。

Effects of entomopathogenic nematodes on the oriental fruit fly, Bactrocera( Bactrocera ) dorsalis (Hendel)

Effects of four entomopathogenic nematode strains, i.e., Steinernema carpocapsae All, Steinernema carpocapsae A24, Steinernema feltiae SN, and Heterorhabditis bacteriophora H06, on the oriental fruit fly (OFF), Bactrocera (Bactrocera) dorsalis (Hendel) were investigated both in the laboratory and field. The results showed that among the four tested strains, the strain S. carpocapsae All displayed the strongest pathogenicity. The LD_ 50 and LD_ 95 of S. carpocapsae All in 3 days after treatment against the 3rd instar larvae were 35.0 and 257.1 infective juveniles/cm2 soil, respectively. The index of population trend (I) and the interference index of population control (IIPC) based on the life table with affecting factors in different stages in the field populations of B. (B.) dorsalis were used to evaluate the control efficacy of S. carpocapsae All against OFF. The field results showed that when S. carpocapsae All nemotodes in 300 infective juveniles/cm2 soil were used to treat the soil, the control efficacy in 9 days after treatment against larvae and pupae reached 86.3%; the I value of OFF was 15.5, significantly lower than 105.9 found in the orchard without nematode treatment; and the IIPC value of OFF in the treated orchard was 0.146, which meant that the population density of OFF in next generation in the treated orchard was reduced to 14.6% of the population density of OFF in the control orchard.