Effect of some botanicals on hemocytes and molting of Papilio demoleus larvae

Abstract

The lemon butterfly, Papilio demoleus whose larvae are serious pest of citrus plant, causes potential threat to the citrus industry. Citrus trees are excellent source of vitamins and its fruits utilized directly by human being. Therefore, P. demoleus should be controlled in eco-friendly manner. Keeping hazardous effects of synthetic insecticides in mind the natural bio-pesticides are being tested here with reference to insects molting and hemocyte counts. In the present study, leaf extracts of Eucalyptus globulus and Ageratum conyzoides and clove extract oiAllium sativum were evaluated for their bio-efficacy against V instar larvae of P. demoleus. The leaf and clove extract of aforesaid plants were prepared by macerating and extracting them in small quantity of Double Distilled Water (DDW). Total Haemocyte Count (THC) and Differential Hemocyte Count (DHC) were conducted and results revealed significant reduction in THC as well as great deal of variation in relative percentage of hemocytes in comparison to their control. The abnormalities in morphogenetic development were exhibited by the production of larval-pupal intermediates, pharate adults and different degrees of wing abnormalities in imagoes. Plant extracts also caused reduction in larval body weight showing their anti-feedant properties. Relatively more significant reduction in body weight was found in Eucalyptus globulus treated larvae. These results revealed that the botanicals used in this study are very economical and eco-friendly to non-target organisms and human being. But these botanicals/bio-pesticides are hazardous to lemon butterfly thus challenging its pest status in the crop field. © 2012 Academic Journals Inc.