In situ polymerization of sodium alginate and polyethylene glycol nano-formulations of acetamiprid against khapra beetle, Trogoderma granarium (Everts) (Coleoptera: Dermestidae)

Abstract

Nano-formulations have been identified as a novel method of integrated pest management due to their increased effectiveness. Acetamiprid is an insecticide belonging to the group of neonicotinoids that selectively binds and interacts with the insect nicotinic acetylcholine receptor site, causing convulsions, paralysis, and ultimately death. Our research describes nano-formulated acetamiprid in situ polymerized using sodium alginate (AL) and polyethylene glycol (PEG). Third instar larvae of the Trogoderma granarium were sprayed using a potter tower for bioassays. LC50 for bulk formulation was 1.48 μg/cm2 and for AL and PEG were 0.85 μg/cm2 and 0.93 μg/cm2, respectively. Data analysis demonstrated that AL was 1.76-fold and PEG was 1.57-fold more toxic than bulk acetamiprid. LT50 for bulk formulation, AL, and PEG were 2104, 9, and 23 min, respectively. The results indicated that AL and PEG were more active and rapidly induced toxicity than bulk acetamiprid, viz., 224.18-fold and 92.58-fold, respectively. In vitro experiments revealed that protein, carbohydrate, glycogen, and lipid contents of treated larvae were significantly decreased. Detoxifying enzymes activities (glutathione S-transferases) were also reduced by AL and PEG-nano-encapsulated formulations but the activity of α-β-esterase were significantly increased. Based on outcomes, nano-formulation can enhance effectiveness of acetamiprid in terms of toxicity.