Evaluation of three inert materials in controlling Cowpea weevil (<em>Callasobruchus maculatus</em> F.) on stored cowpea (<em>Vigna unguiculate</em> L.)

Abstract

Eco-friendly inert materials can be achieved minimizing insect damages, this study was conducted to explore the efficacy of the three inert materials at 20% (w/w) paddy husk ash (PHA), fine dry sea salt and tiny bricks against the cowpea weevil C. maculatus on stored cowpea (V. unguiculata) on the basis of adulticidal effects and asses the influence against germination losses of the seeds. The result exhibited a significant difference (p≤ 0.0001) in their level of weevil attack during the storage. Maximum 100% adult mortality was recorded in the cowpea seeds incorporated with PHA after 96 hours of the treatment followed by dry salt it was observed 94% at the 5th day whereas, tiny bricks killed only 20% weevils as untreated control until 5th day after the treatment. Further, PHA treated seeds much reduced the capable of the egg laying capacity of weevil (9.8± 0.58eggs/ female) as well as minimized the production of new progenies (13.6 ± 0.37) and also there were recorded 0.03% weight loss and zero percent germination losses proving it to be best protectant on stored cowpea. However, significantly (p≤ 0.0001) any adverse effects that, egg laying capacity and new progeny production did not visible in dry salt up to 90 days after the treatments except minimize the germination loss. Among the inert materials used, tiny bricks were found ineffective to cause adult mortality, fecundity and adult emergency in F1 generation (119.8± 1.78), it was further increased production of new weevils obtained following the next F2 generation (1301 ± 0.65) and play down the losses of weight and germination of the seeds. Considering it was noticed tiny bricks treated seeds significantly equivalence with the level of damage by the weevil C. maculatus in untreated control on stored cowpea.