The Efficacy and Residual Toxicity of certain Granular Insecticides against Mustard Aphid,Lipaphis erysimi (Kalt)

Abstract

The systemic activity of four granular insecticides (phorate 10%, Temik 10%, diazinon 5% and Sevidol [8% carbaryl + 8% gamma-BHC]) was evaluated for the control of mustard aphid, Lipaphis erysimi (Kalt). The granules were applied in the soil to one month old mustard plants transplanted in pots. 3rd and 4th instar nymphs were used for the trial. Mortality counts were made 24 hours after release. Of the insecticides tested, phorate and Temik at 1 lb a.i./ac proved most effective. Temik had a quick knockdown effect as compared to phorate, as it gave 100% control within 24 hours, while with phorate 100% kill was obtained only after 72 hours. Diazinon at 4 lb a.i./ac gave 83.3% kill after 72 hours. Sevidol proved ineffective as an aphidicide. Residual toxicity of three of the granular insecticides, namely phorate, Temik and diazinon, was tested. Phorate and Temik at 1 lb a.i./ac exhibited the same residual toxicity up to 4 weeks, i.e. 100% and 76% kill obtained at the end of 2 and 4 weeks respectively. Although the toxicity of both pesticides gradually declined there was no significant difference in percentage kill over a period of 5 weeks. After 6 weeks, however, the mortality recorded with Temik was 37.1% and with phorate was 51.1%. The residual toxicity of phorate was further found to last up to 8 weeks, when the mortality obtained was 40%. The residual toxicity of diazinon sharply declined within 2 weeks.     

Comparison of structural diversity of tree-crop associations in Peripheral and Buffer zones of Gachabari Sal forest area, Bangladesh

The original version of this article unfortunately contained three mistakes.
（1） The spelling of the [A. Nishad＇] name was incorrect. The corrected spelling is given below.