Studies on the Effectiveness of Botanicals and Insecticides in Prevention of Cross Infestation By Rhyzopertha Dominica (Fabr.) in Stored Wheat

Abstract

The laboratory experiment on storage was conducted at the Agriculture Research Station, Gulbarga during the year 2012-13 over a period 210 days to know the effectiveness of various botanicals and insecticides against Rhyzopertha dominica Fabin two different methods viz. in, Impregnation method and once application method on the surface treatment of gunny bags in botanicals and insecticides once in the beginning. In Impregnation method deltamethrin at 0.005 per cent stood significantly superior over other trea tments in protecting the wheat grains from the infestation of R. Dominica at 30 DAS (98.10 %), 90 DAS (8.30 %), 150 DAS (26.10 %) and at 210 DAS (6.20 %) with a minimum live adult population of R. dominica at 30 DAS (0.00 %), at 90 DAS (8.15 %), at 150 DAS (11.55 %) and at 210 DAS (42.00 %) respectively. Residual toxicity of deltamethrin lasted effectively upto 150 DAS. In once application method, sweet flag (5 %) at 30 DAS and 90 DAS caused the highest mortality of 100.00 and 96.12 per cent with minimum live adult of borer population of 0.00 and 9.00 per cent respectively. In this method residual toxicity of sweet flag lasted effectively upto 90 DAS. Similarly at 150 and 210 DAS deltamethrin at 0.005 per cent remained superior causing a mortality of 70.00 and 60.0 per cent with a minimum live adult population of R. dominica (25.00 and 32.00 % respectively). Among the two different methods impregnation method was found effective where in the toxicity levels of deltamethrin lasted effectively upto 210 days unlike in the once application method though sweet flag remain superior in the beginning upto 90 days but over prolonged storage period deltamethrin remained effective in managing the insect population of R. dominica to a maximum extent.