Toxic Potentials of Some Plant Powders on Survival and Development of <i>Callosobuchus maculatus</i> (F.) and <i>Callosobuchus chinensis</i> L.

Abstract

Leaves of Vitex negundo L., Annona squamosa L., Nicotiana tabacum L., Polygonum hydropiper L. and leaf, bark and seed kernel of Azadirachta indica A. juss. were powdered and admixture at the rate of 1-, 2- and 3g per 50g cowpea seeds. Callosobruchus maculatus (F.) and C. chinensis L. adults of both sexes were released in the treated and control cowpea seeds. The mean numbers of eggs laid by both bruchids was significantly decreased in A. indica seed kernel treated cowpea seeds. The toxic effect of the plant parts were observed up to seven days. Between 26.66% ± 12.01 to 100% mortality rates were recorded for C. maculatus and 86.66% ± 6.66 to 100% for C. chinensis in all the trials. The mortality rates in the untreated control ranges between 10-26%. Very few adults were emerged at A. indica seed kernel treatments. The adult emergence was 5.33% ± 0.88, 4.33% ± 0.88 and 1.66% ± 0.88 for C. maculatus; and 5.33% ± 0.88, 3.66% ± 0.66 and 2.00% ± 0.57 for C. chinensis at the doses of 1 -, 2 and 3g per 50g cowpea seed respectively. No significant weight loss was obtained in tobacco leaf powder and A. indica seed kernel treated seeds for both bruchid species. Among the plant materials highest percentage of weight loss was found in P. hydropiper leaf powder followed by A. indica bark, A. squamosa leaf and V. negundo leaf powder.

Key words: Azadirachta indica; Annona squamosa; Nicotiana tabacum; Polygonum hydropiper; Vitex negundo; cowpea weevil; pulse beetle; Vigna unguiculata

DOI: 10.3329/jles.v3i0.7437

J. Life Earth Sci., Vols. 3-4: 1-6, 2009