Abstract

CO-TOXICITY STUDY OF IMIDACLOPRID AND A SYNERGIST PBO ON ALPHITOBIUS DIAPERINUS (COLEOPTERA: TENEBRIONIDAE) FOR BIOLOGICAL SAFETY OF STORED GRAINS AND CEREALS

Akter Mst Yeasmin†, Talukdar Muhammad Waliullah†*, Nafisa Islam, Md. Ashraful Alam, ASM Shafiqur Rahman

Abstract

To investigate the co-toxicity and co-efficient activity of imadacloprid (imitaf 20EC), a neonicotinoid and piperonyl butoxide (PBO) against Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae). Dose mortality test was done by the residual film assay technique. Statistically the dose mortality relationship was expressed as a median lethal dose (LD50) by the probit analysis. The regression lines and isoboles were drawn using the Fig-P (Biosoft) package. The Coefficient values showed that all ratios of imadacloprid and piperonyl butoxide offered synergistic action to both larvae and adult. We observed that the toxicity of the imadacloprid was decreased as the ratio (amount) of PBO was increased. The individual LD50 value of imadacloprid for adult is 0.6803μgcm-2. But in the mixture, the share of imadacloprid are 0.0506, 0.0559, 0.0531 and 0.0405μgcm-2 at ratios of 1:1, 1:3, 1:5; 1:10 when PBO causes reduction of dose level of 92.56%, 91.78%, 92.19% and 94.04% respectively. In case of larvae the individual LD50 value of imadacloprid is 0.5168μgcm-2. But in the mixture, the share of imadacloprid are 0.0568, 0.0297, 0.0241 and 0.0185μgcm-2 at ratios of 1:1, 1:3, 1:5; 1:10 when PBO causes reduction of dose level of 89%, 94.25%, 95.33% and 96.42% respectively. The study suggests that the mortality rate of lesser mealworm is increase with the increase of insecticide dose. The LD50 values of the insecticides are inversely related to the toxicity of the insecticides i.e. higher the LD50 value lower the toxicity of the insecticide.

Keywords: Neonicotinoid, Metabolic inhibitor, Neurotoxin, Acetone, Darkling beetle, Integration of pest management, Residual film assay.