一种对桃小食心虫高毒力的斯氏线虫Steinernema sp.(CB-2Y)

本研究在室内用“沙埋法”比较了两种斯氏属昆虫病原线虫Steinernema sp.(CB-2Y)和S.feltiae Agriotos对桃小食心虫的侵染力,结果表明CB-2Y线虫对桃小食心虫幼虫和冬茧的侵染力都高于Agriotos线虫。接线虫笫7天桃小食心虫LD50,CB-2Y组为49条线虫,而Agriotos组为158条;冬茧的LD50分别为1330条和24046条。在桃小冬茧开始活动期(6月15日)分别施用两种线虫,一个月后检查桃小食心虫成虫羽化率,CB-2Y线虫的控制效果明显优于Agriotos,在1024条线虫/桃小食心虫冬茧时(75条/cm~2),越冬代桃小食心虫的羽化率分别为8.2％和29.2％。

A COMPARATIVE STUDY ON THE VIRULENCE AGAINST CARPOSINA NIPPONENSIS CLEP. , CARPOSINIDAE] BETWEEN A NEWLY ISOLATED INSECT NEMATODE STBINERNEMA SP. (CB-2Y) AND STEINERNEMA FELTIAE AGRIOTOS

Laboratory experiments were conducted in Beijing to compare infectivities of two steinernema nematodes against Carposina nipponensis,a key pest boring various fruits, using the "Sand-Imbedding Method" . The nematodes were Steinernema feltiae agriotos, which has been used in controlling the moth in China, and Steinernema sp. (CB-2Y) , which was isolated from Hebei Province in 1988. The results showed that the new CB-2Y nematode had a significantly higher infectivity to both larvae and overwintering cocoon of C. nipponensis than S. feltiae agriotos. The LD30 of larvae infected by CB-2Y and the strain agriotos on the 7th day after inoculation was 49 and 158 infective juveniles, respectively. The LD50 to the overwintering cocoon infected by the two nematodes wsa 1,330 and 24,046 infective juveniles, respectively. The percent adult emergence of the overwintering generation of C. nipfonensis was significantly different in the treatments of CB-2Y and agriotos. AtJ a dosage of 1,024 infective juveniles per overwintering cocoon (or 75 juveniles/cm* of soil) , the adult emergence rate was 8.2% and 29,2%, respectively, one month after the soil treatment.