The field experiment was conducted during kharif in year 2023-24 to study the effect of water pH on bioefficacy of insecticides against sucking pests of Bt cotton.” at Seed Technology Research Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola. The experiment was carried out in Factorial Randomized Block Design (FRBD) of two factors i.e. Factor A i.e. insecticides and Factor B i.e. water pH levels with nine treatments replicated three times. The treatment details of experiment, spraying three insecticides (i.e. Afidopyropen 50g/L DC, Fenpyroximate 5% EC, Spiromesifen 22.90% SC) with Acidic, Alkaline, and neutral water pH levels. The study revealed that, Among insecticides, The leaf hopper population identified significantly lowest in treatment of Afidopyropen 50g/L DC was shown most effective insecticide treatment against leafhopper, it was at par with Fenpyroximate 5%EC followed by Spiromesifen 22.90% SC. Among water pH levels. The leaf hopper population found to be lowest under treatment with acidic water (5-6 pH) it was at par with neutral water (7 pH) and highest population was observed in alkaline water (8-9 pH). In terms of the interaction impact, leafhopper control on Bt cotton was more effective by insecticides in acidic and neutral water than by those applied to alkaline water. The yield was recorded significantly highest in Afidopyropen 50g/L DC (13.63 q ha-1). It was at par with Spiromesifen 22.90% SC and yield was observed lowest in Fenpyroximate 5%EC. Among water pH levels, the maximum yield was obtained in treatment of acidic pH (12.78 q ha-1) followed by neutral pH which is at par with acidic pH. The yield was recorded lowest in alkaline pH. Based on ICBR, the result among different treatments indicated that treatment with of Afidopyropen 50g/L with neutral pH gave the highest incremental cost benefit ratio of 1:9.60 than other treatments. To control the number of cotton leafhoppers, cotton growers can apply an alternate spray of concluded insecticides at a suitable pH level of water

Bt Cotton, Cost Benefit Ratio, Efficacy, Insecticides, leafhopper, Water pH levels, Yield

The results of this study show that, when compared to the chemical insecticides mentioned above, Afidopyropen 50g/L DC was the most effective insecticide against the population of cotton leafhoppers. It was at par with Fenpyroximate 5%, which was the next best insecticide fallowed by Spiromesifen 22.90% SC. The acidic spray solution decreased leafhopper population the most effectively among the water pH levels, followed by neutral, which was at par with acidic pH, and The alkaline spray solution had the largest leafhopper population. In terms of the interaction impact, leafhopper control on Bt cotton was better served by insecticides in acidic and neutral water than by those in alkaline water

Praful P. Kowa, Gajanan K. Lande and Mohan S. Shelke (2024). Effect of Water pH on Bioefficacy of Insecticides Against Leafhopper Amrasca biguttula biguttula (Ishida) on Bt cotton. Biological Forum – An International Journal, 16(9): 185-190