Efficacy of Oxydimethon Methyl (EC 25%), Diazinon (EC 60%), Acetamiprid (WP 20%) and Imidacloprid (SC 35%) with pH Reducer Solution, Lonsul, Against Aphis fabae

In this study, Effect of water pH correction on short and long term toxicities of four insecticides, oxydimethon methyl (EC 25%), diazinon (EC 60%), acetamiprid (WP 20%) and imidacloprid (SC 35%), were evaluated against population of A. fabae in compeletely randomised block design under field conditions during 2010-2013. Recommended Field concentrations (RFC) , 50 and 25% RFC of each insecticide were made by original and corrected water (by pH reducer solution of Lonsul®). Corrected mortality precentage of the aphid after 24 h and cumulative aphid days (CAD) during various sampling days after treatments were determined and analysed in both growing seasons to evaluate short and long term effects of water correction on the efficacy of the insecticides . Water pH modification had no significant effects on the insecticides short tem efficacie. By pH modification, oxydimethon methyl, diazinon and imidacloprid at 50% RFC caused 99.5-99.9, 98.5-99.7 and 98.1-99.6% reduction in A. fabae population wich were not significantly different from the insecticide application at 100% RFC. The pesticide residue persisted to the end of sampling period (6 weeks in pH modified water compared to 1-2 weeks in original water) , but in acetamiprid plots with pH modified water treatments, CAD at 50% RFC were 103 and 2345 aphids and at 25% RFC CAD were 1532 and 22679 aphids which were significantly higher than the same treatments with original water (453 and 805 aphid at 25% RFC and 76 and 36 aphids at 50% RFC) in the fisrt and seocond growing seasons, respectively.