玫烟色拟青霉亚致死浓度对小菜蛾取食和成虫生殖的影响

Sublethal Effects of Paecilomyces fumosaroseus on Feeding and Fecundity of the Diamondback Moth,Plutella xylostella

在室内测定了玫烟色拟青霉菌株SCAU-PFCF01的亚致死剂量对小菜蛾幼虫取食量、蛹重、化蛹、羽化、成虫寿命和雌蛾产卵量的影响。结果表明,用玫烟色拟青霉1×102和1×103孢子/ml处理小菜蛾2龄幼虫后,其幼虫期的总取食量较对照相比分别降低29.3%和54.1%。处理4龄幼虫后,玫烟色拟青霉导致其化蛹率、蛹重、羽化率、成虫寿命及成虫产卵量显著下降,1×103孢子/ml处理4龄幼虫后小菜蛾的平均蛹重、雌成虫寿命、雄成虫寿命、成虫的产卵量分别为4.3mg、15.3d、17.2d和135.1粒/雌,显著低于对照。

The diamondback moth, Plutella xylostella, is an important insect pest of cruciferous vegetables in South China and has developed higher resistance to insecticides commonly used in the field. In an effort to select effective biological control agents against the diamondback moth, sublethal effects of a Paecilomyces fumosaroseus strain （SCAU-PFCF01） on the feeding, development and fecundity of the diamondback moth were studied in the laboratory. Results showed that food consumption of the larvae could be reduced by P. fumosaroseus conidia at sublethal concentration. When the 2nd instar larvae were treated with 102 and 103 conidia/ml, the total food consumption of larval stage was reduced by 29.3 % and 54.1%, respectively. Although the sublethal concentration could not kill all the 4th instar larvae, it could significantly decrease the pupation rate, emergence rate, longevity and fecundity of adults. When treated with concentration of 103 conidia/ml at the 4th instar larvae, the average weight of pupa （4.3 mg）, longevity of adult （ 15.3 d for male, 17.2 d for female） and fecundity （ 135. I eggs/female） were significantly lower than that of control, respectively.