Experimental Confirmation of the Bruchidae Natural Parasitism Efficacy using an Innovative Device, Friendly to the Environment

ABSTRACT

Due to the high cost factor the existing methods of managing pests in stored grains are not feasible for small-scale farmers. Management of pests by using locally and naturally available materials will be affordable by farmers and it will also be environment-friendly. In the present work, an innovative device (parasitoid facilitator bin), friendly to the environment with provision for the free movement of parasitoids into the bin was designed and employed to manage one of the major pests of pulses, the cowpea weevil, Callosobruchus maculatus (F.). The parasitoids that naturally entered the experimental setup were the egg parasitoid, Uscana lariophaga (S.) and the larval and pupal parasitoid, Dinarmus basalis (R.). The number of pests (all life stages) gradually decreased in grains stored in bins where there was provision for the movement of natural parasitoids. Adult emergence was very high in the control (320 to 416 per 500 egg-carrying grains), whereas it was much lower (33 to 46 per 500 egg-carrying grains) in the experiment, i.e. in the parasitoid facilitator bin. The adult emergence inhibition index in the experiment was 81.21%. In areas where natural parasitoids are abundant, this bin can be a boon to the farmer and this may have practical implications in the development of efficient large- scale storage systems.

Keywords:

• environmentally-friendly device
• natural parasitism
• biological control
• Callosobruchus maculatus
• Uscana lariophaga
• Dinarmus basalis