EFFICACY OF BACILLUS THURINGIENSISON LARVAE OF JUNONIA A TLITES DAMAGING HYGROPHILA DIFFORMISMiD IT'S ON FARM METHOD OF SMALL SCALE PRODUCTION

摘要

Water gardening is a burgeoning business that has a long track record of growth. Aquatic ornamental plants are used for the decoration of ponds or aquaria. Hygrophila difformis is a textbook species for the planted aquarium novice. The larvae of Junonia atlites emerged as a pest in the variety of H. difformis and its larval stages damaged severely on the leaves of this plant. The nature of damage and biology of the J. atlites on H. difformis were studied. The life cycle of 7. atlites was completed in26±2 days. Larval stage consists five distinct instars. The peak population of J. atlites was reached in March 13th week (54%) and April 16th week (62%). Field and laboratory assays were performed with Bacillus thuringiensis (8t) against J. atlites. Btat different concentrations (0.5, 1,1.5, 2, 3 and 5 g/L) were tested against last instar larvae of J. atlites. The concentrations of 1, 1.5, 2, 3 and 5 g/L caused 78, 82, 92 and 100% mortality of larvae of J. atlites, respectively at 2 days after treatment (DAT). Concentrations of 1, 1.5, 2, 3 and 5 g/L caused 100% mortality at 3 DAT. No damage was observed on the leaves one DAT due to cessation of larval feeding at all concentrations. Bt at 1 g/L was the optimum concentrations for the control of larvae of J. atlites. The coir dust extract was identified as a basal media for small scale multiplication of St. Coir dust extract based Bt formulations of 10, 20, 30, 40 and 50 mL/L performed 20%, 35.53%, 53.33%, 66.67% and 100% respectively at 3 DAT. Theseresults revealed that Bt formulations at 50 mL/L was the best concentration and could be applied at the field for controlling the larvae of J. atlites.