Relative Efficacy of Some Chitin Synthesis Inhibitors on the Mortality of Okra Jassid, <i>Amrasca biguttula biguttula</i> (Ishida)

Abstract

In this laboratory study, three chitin synthesis inhibitors (CSIs) <i>viz.</i> Tacoma 40SC (Buprofezin), Heron 5EC (Lufenuron) and Pyrifen 10.8EC (Pyriproxifen) were evaluated with three concentrations of each through different application methods <i>viz</i>. direct or topical, indirect or leaf-dip and combined (Direct + Indirect). Data on jassids mortality was collected at 3 and 7 days after treatment (DAT) application. Our present study showed that all of the CSIs had significant effect on the mortality of jassid. In all cases, mortality was clearly dose, time and application method dependent. It has been seen that higher concentrations were found to be more effective than lower concentrations. Moreover, significant level of mortality was found at 3DAT but reached to the peak level at 7DAT in case of all selected CSIs. Bioassay study has showed that all the selected CSIs became able to enter the insect body through contact as well as stomach action to disrupt moulting process by inhibiting chitin synthesis that confirmed the contact and systemic actions of the selected CSIs. Moreover, protocols developed in this study for jassids collection and their safe transferring inside the petridishes would be a useful and convenient approach for the researchers.