›› 1996, Vol. 39 ›› Issue (3): 238-245.

• RESEARCH PAPERS • Previous Articles     Next Articles

A STUDY ON THE RESISTANCE OF DIAMONDBACKMOTH TO BACILLUS THURINGIENSISIN GUANGDONG

Feng Xia Chen Huanyu Shuai Yingyuan Xie Qihe Lu Yuechang   

  • Online:1996-08-20 Published:1996-08-20

Abstract: The diamondback moth (DBM), Plutella xylostella L, is one of the most destructive pest of crucifer crops in Guangdong Province, China. The resistance of field strains of DBM from Shenzhen (SZ) and Guangzhou (GZ) city of Guangdong Province to conventional microbial insecticides has been investigated. Results showed that the strains of SZ and GZ had resistance to synthetic pyrethroids, organophoshorus insecticides, carbamates as well as insect growth regulators, but only the strains of SZ showed resistance to microbial insecticide (B. Thuringiensis). Fenvalerate was greatly synergized with piperonyl butoxide (PB) or o,o -diethyl-o-phenyl-thiophosphate (SVI). An addition of PB, SV1 and TPP (triphenyl phosphate)to microbial insecticide BT resulted in no synergism, indicating that the resistantmechanism of DBM to BT does not include microsomal oxidation of MFO and esterases. Susceptible of DBM would obtain resistance to Dipel (B. thuringiensis var. Kurstaki) soon, when every generation was bred with Dipel under laboratory condi-tion (23℃-30℃ , L: D =12:12). The LC50 of F0, F5 F12 and F18 were 30.33, 298.00,695.33 and 1077.33mg/L, respectively, the LC50 of F18 was 35.5-fold as that of F0.On the other hand, during the 20 generations of rearing without insecticide pressure,recovery of sensitivity to BT was detected, so was the recovery of sensitivity tochemical insecticides, but the recovery of sensitivity to insect growth regulators (chlorfluazuron) and synthetic pyrethroids was very slow. Fortunately, no crossresistance was found between the chemical and microbial insecticide (BT) used.

Key words: Plutella xylostella, Bacillus thuringiensis, insecticide resistance, cross-resistance, synergism