›› 2008, Vol. 51 ›› Issue (10): 1044-1049.

• RESEARCH PAPERS • Previous Articles     Next Articles

Resistance stability and re-growth in adults of the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae) to trichlorphon

ZHANG Yu-Ping   

  • Online:2010-07-29 Published:2008-10-20

Abstract:

In the laboratory, two different high-level resistant strains TrR50 and TrR90 of the oriental fruit fly, Bactrocera dorsalis to trichlorphon were established after 14 generation selection by using the concentrations of LC50 and LC90 of trichlorphon, the TrR50 and TrR90 strains without exposure to any insecticides were kept for 19 generations, and the resistance recession to trichlorphon were studied. At the same time, the re-growth resistance was monitored after the two strains were bred for 4 generations under insecticide-free condition, and then selected with trichlorphon for 12 generations. The results showed that the resistance of the two resistant strains was all  instable, but their depression rates were different. After Tr90 and TrR50 were selected for 4 and 7 generations respectively, their resistance decreased to one third of the original level. Then the resistance of the two strains was depressed slowly, and after the two strains were selected for 19 generations, their resistance kept at a low level but was unable to be depressed to the susceptible level. Through equation fitting of resistance depression tendency, it was found that the resistance depression of the two strains was both in line with S-curve model. The resistance re-growth of the two strains was different. After selection with trichlorphon for 6 generations, TrR50 resistance went up rapidly which was close to the original level; but only after selection for 9 generations with trichlorphon,

TrR90 resistance began to increase rapidly, which was close to the original level only after 12 generation selection. The results of the equation fitting of resistance re-growth tendency showed that resistance re-growth of the two strains was quite different, and the fitting curve of TrR50 strain was in line with the logistic model, while that of TrR90 was in line with quadratic curve model.

Key words: Bactrocera dorsalis, trichlorphon, insecticide resistance, resistance stability, resistance re-growth