COMPARATIVE ANALYSIS OF DIFFERENT STORAGE CHEMICALS (PHOSPHINE, PERMETHRIN POWDER AND PIRIMIPHOS METHYL 2% DUST) ON POST HARVEST PEST OF COWPEA Callasobruchus maculatus (Fab.)

The study was conducted in the Entomology Laboratory, College of Agriculture, Maiduguri, to determine the effectiveness of three insecticides (Permethrin, Phosphine and Pirimiphos methyl) on Callasobruchus maculatus a post harvest pest of stored cowpea. The experiment was 2 × 4 factorial laid out in Completely Randomized Block Design (CRBD) (i.e four treatments under two regimes) replicated three times. The treatments were T₁ (Permethrin )  T₂ (Phosphine), T₃ (Pirimiphos methyl) and T₄ (control).  The weight of 200 seed-sample each was placed in a plastic container. Ten unsexed C. maculatus adults obtained by sieving infested cowpea in a local market, were introduced into each of the twenty-four containers. At the end of the two and four months of storage, the results revealed that the weight loss for the beans subjected to the different treatments showed weight loss of  29.48% of its initial weight for control, while percentage loss in weight for permethrin was 16.33%; phosphine 9.68% and pirimiphos methyl  20.26%. The results also showed that after the two months of storage, the weight (46.67g) of cowpea treated with phosphine was significantly more than those treated with permethrin (42.67g) and pirimiphos methyl (42.0g) while that of control recorded the lowest (36.67g). There was significant difference between the mean number of undamaged seeds for the four treatments in regime one (two months). The highest number of undamaged seeds of 146.6 was recorded in container treated with phosphine; 110 in container treated with permethrin; 109 in container treated with pirimiphos methyl and the least (84.3) seeds was that from the control.  Therefore, phosphine was found to be more effective against the stored cowpea beetle.