Abstract

CYTOTOXIC EFFECT OF FENITROTHION AND ITS SYNERGIST PBO ON ALPHITOBIUS DIAPERINUS (COLEOPTERA: TENEBRIONIDAE) FOR BIOLOGICAL SECURITY OF STORED GRAINS AND CEREALS

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

Abstract

To investigate the co-toxicity and co-efficient activity of fenitrothion (sumithion 50EC), an organophosphate and piperonyl butoxide (PBO) against Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae). Insecticidal activity 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 fenitrothion and piperonyl butoxide offered synergistic action to both larvae and adult. We observed that the toxicity of the fenitrothion was decreased as the ratio (amount) of PBO was increased. The individual LD50 value of fenitrothion for adult is 0.8737μgcm-2. But in the mixture, the share of fenitrothion are 0.2648, 0.5187, 0.5864 and 0.8242μgcm-2 at ratios of 1:1, 1:3, 1:5; 1:10 when PBO causes reduction of dose level of 84.84%, 85.16%, 88.81% and 91.42% respectively. In case of larvae the individual LD50 value of fenitrothion is 0.7328μgcm-2. But in the mixture, the share of fenitrothion are 0.1515, 0.1583, 0.1331 and 0.1062μgcm-2 at ratios of 1:1, 1:3, 1:5; 1:10 when PBO causes reduction of dose level of 89.66%, 94.60 %, 96.98% and 98.68% 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: Organophosphate, Neurotoxin, Acetone, Darkling beetle, Integration of pest management, Residual film assay.