Sublethal Doses of Insecticides Affect the Fecundity and Fertility of the Chrysodeixis includens?

摘要

The objective was to determine lethal concentrations and to evaluate the effects of sublethal doses of insecticides on style="font-family:Verdana;">Chrysodeixis style="font-family:Verdana;">includens style="font-family:Verdana;"> under laboratory conditions. The standard population of style="font-family:Verdana;">C. style="font-family:Verdana;">include style="font-family:Verdana;">n style="font-family:Verdana;">s style="font-family:;" "=""> style="font-family:Verdana;">was kept on artificial diet under controlled conditions (25 style="font-family:;" "=""> style="font-family:Verdana;">°C ± 5°C, 60% ± 10 RU, 12:12 h). The active principles used were style="font-family:Verdana;">B. style="font-family:Verdana;">thuringiensis style="font-family:Verdana;">, style="font-family:Verdana;">Indoxacarb and style="font-family:Verdana;">Teflubenzuron. The CL _{style="font-family:Verdana;">25} style="font-family:Verdana;"> and LC _{style="font-family:Verdana;">50} style="font-family:Verdana;"> obtained from dose response curve (estimated from eight concentrations of each active principle) were diluted in water and applied to the back of third instar caterpillars and compared to the control (water). The insecticides used showed lethal and sublethal effects in style="font-family:Verdana;">C. style="font-family:Verdana;">includens style="font-family:Verdana;">. style="font-family:Verdana;">Bacillus style="font-family:Verdana;">thuringiensis style="font-family:Verdana;"> was 6.21 and 2.79 times more toxic to soybean looper when style="font-family:Verdana;">compared to the products Indoxacarb and Teflubenzuron, respectively. Insecticides style="font-family:Verdana;">applied to the caterpillars reduced survival and affected the biomass gain with increased larvae and pupae longevity, with a significant reduction in fertility (40%) and fecundity (94.97%) in adults. In the present study it was observed that both survival and larval biomass gain have a direct effect on fecundity and fertility, respectively. Therefore the active ingredients style="font-family:Verdana;">Indoxacarb style="font-family:Verdana;">, Teflubenzuron and style="font-family:Verdana;">B. style="font-family:Verdana;">thuringiensis style="font-family:Verdana;"> can be used in rotation as a tool in the style="font-family:Verdana;">C. style="font-family:Verdana;">includens.