Abstract

CO-TOXICITY EVALUATION OF LAMBDA-CYHALOTHRIN AND ITS SYNERGIST PBO FOR SUSCEPTIBILITY OF ALPHITOBIUS DIAPERINUS (COLEOPTERA: TENEBRIONIDAE)

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

Abstract

To investigate the co-toxicity and co-efficient activity of λ-cyhalothrin (karate 2.5EC), a pyrethroid 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 λ-cyhalothrin and piperonyl butoxide offered synergistic action to both larvae and adult. We observed that the toxicity of the λ-cyhalothrin was decreased as the ratio (amount) of PBO was increased. The individual LD50 value of λ- cyhalothrin for adult is 0.0292μgcm-2. But in the mixture, the share of λ-cyhalothrin are 0.0125, 0.0145, 0.0182 and 0.0233μgcm-2 at ratios of 1:1, 1:3, 1:5; 1:10 when PBO causes reduction of dose level of 78.76%, 79.10%, 89.72% and 92.80% respectively. In case of larvae the individual LD50 value of λ-cyhalothrin is 0.0813μgcm-2. But in the mixture, the share of fenitrothion are 0.0155, 0.0250, 0.0269 and 0.0287μgcm-2 at ratios of 1:1, 1:3, 1:5; 1:10 when PBO causes reduction of dose level of 93.23%, 94.34%, 98.40% and 98.40% 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: Pyrethroid, Metabolic inhibitor, Neurotoxin, Acetone, Darkling beetle, Integration of pest management, Residual film assay.