Effects of sublethal doses of triazophos and chlorpyrifos on the population growth and yolk protein content ofSesamia inferens (Walker)
Author of the article:YANG Guo-Qing** LI Li GE Lin-Quan WU Jin-Cai***
Author's Workplace：Horticulture and Plant Protection College, Yangzhou University, Yangzhou 225009, China
Key Words：triazophos, chlorpyrifos, Sesamia inferens, population growth
Abstract：[Objectives] To understand the ecological mechanisms of natural population growth of the pink stem borer (PSB) Sesamia inferens (Walker), and the effects of sublethal doses of striazophos and chlorpyrifos on its population growth and yolk protein content. [Methods] The toxicity of triazophos and chlorpyrifos, and their effect on population growth parameters and yolk protein content, were assessed using the dipping and topical application methods for 1st and 3rd instar larvae respectively. [Results] Our results indicate that larvae were more sensitive to triazophos than chlorpyrifos. The weight of pupae developed from 1st and 3rd instar larvae treated with LC20 or LD20 of triazophos, the number of eggs laid by emergent adult females, and the yolk protein content of females all increased significantly. In contrast, chlorpyrifos had no obvious effect on population growth. [Conclusion] Our findings indicate that sublethal doses of triazophos stimulate the reproduction of PSB and may thereby promote outbreaks of this pest.