Abstract

Efficacy of long-lasting polypropylene storage bags incorporated with deltamethrin insecticide  developed by Vestergaard Frandsen SA. to protect grains (cowpea and maize) from stored products insect damage was compared to grains admixed with Permethrin at 2.5 ppm stored in Polypropylene (PP) bags and untreated grains stored in PP bags investigated in the laboratories of Nigerian Stored Products Research Institute, Ilorin, Kwara State, Nigeria in 2013. Callosobruchus maculatus Fab. (Coleoptera: Bruchidae), Sitophilus zeamais L. (Coleoptera: Curculionidae), Rhyzopertha dominica Fab. (Coleoptera: Bostrichidae) and Tribolium castaneum Herbst. (Coleoptera: Tenebrionidae) adults were used as test insects to determine the contact-sensitivity of each pest to deltamethrin insecticide treated storage bags nd PP bags for different exposure times; attack to stored grains by preventing pest entry or exit through treatment storage bags as well as effect of insect infestation on grain quality. Test insects exposed to deltamethrin insecticide treated  storage bags recorded 90% knockdown compared to 0% in untreated PP bags after 72 h and adults could not chew/bore through the deltamethrin insecticide treated  storage bags either from inside or outside at 72 h respectively after treatment compared to untreated PP bags where adult test insects chewed/bored either from inside or outside within 24 h. Control set up by retaining insects without feed to check mortality recorded 65-90% death of the test insects due to starvation after 7 days.  Simulated study on insect infestation of grains in deltamethrin insecticide treated  storage bags compared to grains treated with Permethrin at 2.5 ppm and stored in PP bags recorded higher percentage mortality of the test insects in deltamethrin insecticide treated  storage bags than in PP bag. There was no change in moisture content, crude protein, ash, fiber, oil, carbohydrate of cowpea or maize grains stored in treatment bags after 6 months storage period. The deltamethrin insecticide treated storage bags are recommended because of their ability to control the target insects or pests in general.  Further study to conduct a field trial using the insect incorporated bags in selected household and traders grain stores was recommended.

Key words: deltamethrin insecticide treatedstorage bags, test insects, chew/bore, stored grains, grain quality.