Lethal and sublethal effects of a chitin synthesis inhibitor, lufenuron, against Glyphodes pyloalis Walker (Lepidoptera: Pyralidae)

Glyphodes pyloalis Walker is a serious pest of mulberry trees in Iran. In this study, lethal (LC۵۰ = ۱۹ ppm) and sublethal effects (LC۱۰ = ۳.۷۴ andLC۳۰ = ۹.۷۷ ppm) of lufenuron were evaluated against ۴th instar larvae of G. pyloalis. After treating the larvae at LC۳۰ and LC۵۰ level, most of them died during the molting process and only a few individuals developed to the ۵th larval instar. The highest rate of mortality wasobserved in ۵th larval (۶۸.۴۲%) and pre-pupal (۵۹.۵۷%) stages at LC۵۰ concentration. Also, lufenuron caused an increase in larval, pre-pupal and pupal developmental periods. The successful pupation decreased to ۵۳.۶۴% at the LC۳۰. Also, no prepupa molted to pupation after treatment of larvae at the LC۵۰. Larval weight was significantly reduced at ۴۸, ۷۲ and ۹۶ h after treatment, compared to the control. Adult emergence and female longevity were also reduced at LC۳۰. The LC۳۰ of lufenuron negatively affected reproduction of G. pyloalis. Larval content of carbohydrate and protein were decreased significantly ۴۸ and ۷۲ h after treatment, however, lipid and glycogen content were decreased significantly only ۷۲ h after treatment at LC۱۰, LC۳۰ or LC۵۰. Findings indicated adverse effects on some biological and biochemical parameters at lethal and sublethal concentrations of lufenuron which necessitate further investigations for its application in an integrated management of G. pyloalis.

کلیدواژه ها:

Glyphodes pyloalis ، lufenuron ، fecundity ، sub-lethal effects ، IGR