Studies on the Efficacy of Various Botanicals and Insecticides Against Sitophilus Oryzae (Linn.) in Stored Wheat

Abstract

The storage experiment was conducted at the Agriculture Research Station, Gulbarga during the year 2012- 13 over a period of seven months to know the effectiveness of various botanicals and insecticides against Sitophilus oryzae (Linn.) in 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 treatments in protecting the wheat grains from the infestation of S. oryzae at 30 DAS (100 %), 90 DAS (80.10 %), 150 DAS (50.20 %) and 210 DAS (11 %) respectively with a minimum live adult at 30 DAS (0.00 %), at 90 DAS (7.00 %), at 150 DAS (12.12 %) and a t 210 DAS (25.20 %) respectively. Residual toxicity of deltamethrin lasted effectively upto 150 DAS. In once application method, sweet flag (5.00 %) a t 30 DAS and 90 DAS, caused the highest mortality of 99.10 and 97.12 per cent respectively with minimum live adult weevil population of 0.00 and 14.00 per cent respectively, however 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 79.12 and 66.30 with a minimum live adults population of S. oryzae (11.65 And 29.55 %) 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 remained superior in the beginning upto 90 days but over prolonged storage period deltamethrin remained effective in managing the insect population of S. oryzae to a maximum extent.