EFFECTS OF POPULATION DENSITY AND STORAGE DURATION ON THE DEVELOPMENT OF CALLOSOBRUCHUS SUBINNOTATUS IN STORED BAMBARA GROUNDNUT (VIGNA SUBTERRANEAN (L.) VERDCOURT)
Maina, Y. T.; Degri, M. M. and Sharah, H. A.
Journal Title:Journal of Environmental Issues and Agriculture in Developing Countries
An experiment was conducted in the Entomology Laboratory, Department of Crop Protection, Faculty of Agriculture, University of Maiduguri in 2010. The aim was to determine the effect of Population density and storage duration on the development of Callosobruchus subinnotatus in stored bambara groundnut (Vigna subterranean (L.) Verdcourt) with different levels of infestation (2, 3, 4 and 6 pairs of C. subinnotatus) per 100g of bambara groundnut and stored for three months duration under prevailing tropical storage temperature of 30 - 32o C. The results showed that as the population density of C. subinnotatus increases with increasing storage duration the more the damage done to bambara groundnut. The mean number of eggs laid at different levels of infestation increase with the storage duration indicating a significant difference between the first, second and the third month. Adult emergence in treatments infested with two pairs at the third month has a higher mean number of adults compared to those of first and second month which are also applicable to 3, 4, and 6 pairs. The percentage seed damage of bambara groundnut done infested with two pair of C. subinotatus and stored for three months was higher with mean number of 87.84% while four and six pairs gave 99.66% and 99.33% respectively. The severity of damage caused was more in the third month compared to that of first and second month regardless of the level of infestation. The study submitted that the longer the storage duration, the more economic damage stored produce will suffer due to increase egg laying, increase adult emergence and increase percentage damage of seeds which result to high severity of damage.