Utilization of solar heat in the control of cowpea bruchid callosobruchus maculatus f. (coleoptera: bruchidae) in freshly infested cowpea vigna unguiculata walp

Abstract

Cowpea bruchid, Callosobruchus maculatus Motschulsky is a very serious primary pest of stored cowpea grains with 30-100% loss potential. This study is therefore aimed at evaluating the efficiency of solar heat in the management of this pest. The experiment was carried out from May to June, 2024 in the laboratory of the Department of Crop Protection, Modibbo Adama University, Yola laid in a randomized complete block design (RCBD) with three replications. Data collected were subjected to analysis of variance and means separated using Least significant difference LSD at (a = 0.05). Results of the biochemical constituents after the experiment showed significantly higher levels of dry matter and nitrogen free extract, low levels of ash and lipid, appreciable level of crude protein and fibre. Though, before the experiment the trend follows the same pattern. The effects of the sun, affected all the development stages of C. maculatus and the adult stage, where mortality rate decreases as the exposure period to the solar heat increases during the assessment period. The control (unexposed) had the highest number of mortality of C. maculatus, from larva stage to pupa. Highest number of eggs laid was observed in the control treatment was 52, while the exposed treatment had 26.0, 18.0 and 17.67 at 1, 2, and 3 hours, respectively. Cowpea grain damage and grain weight loss also follows same trend, where it decreases as the exposure period increases, while the control had the highest. This finding also indicated increase in germination with increase in exposure periods of 8.0, 8.67 and 9.67 at 1, 2, and 3 hours of exposure, while the control had the lowest germination rate of 2.33 seeds. This study therefore evaluated the effects of solar heat and its promising potentials in the control of C. maculatus in stored cowpea that can be incorporated into an integrated pest management strategy.