Insecticidal Comparison of Botanicals and Synthetic Insecticide on Cowpea Bruchid, Callosobruchus maculatus (Fab.) [Coleoptera: Chrysomelidae] Development on Vigna unguiculata (L.) Walp

摘要

Background and Objectives: Cowpea seed bruchid, a cosmopolitan field-to-insect pest of stored cowpea. Efficient and effective control were achieved using synthetic chemicals but with consequences on human and the environment. The study was conducted to compare the effect of botanicals and a synthetic insecticide on Cowpea Seed Bruchid (CSB) development and also to identify chemical constituents in catmint that are pesticidal. Materials and Methods: About 30 g of uninfested Sampea 13 cowpea seeds were place in plastic containers measuring 8.80 (outside lid diameter) and 3.80 cm (depth). Five grams of each treatment were separately measured into the plastic containers and shaken. Five pairs of approximately one day old CSB were artificially introduced in to the each cup. The cups were covered with a muslin cloth and fastened with a rubber band to disallow CSB escape, but cut opened to allow aeration. The experiment was arranged in a completely randomized design and replicated four times. Parameters measured were on mortality, oviposition and number of progeny emergence. The data was subjected to analysis of variance and means were separate using LSD at 5% probability level. Results: The results obtained showed a significant difference (p 0.05) on mortality between the treatments and the control. Highest mortality counts were recorded in pestox (6.00) 24 h after infestation. Significantly (p 0.05 ) higher number of eggs were laid in the control compared to botanicals which were statistically similar. There was no significant difference (p 0.05) among the botanicals and pestox on mean number of progeny emergence. However, high mean adult emergence was recorded in the control (18.50). Phyto chemical analysis of catmint revealed the presence of insecticidal secondary metabolites such as flavonoids, tannins, saponins and alkaloids. Conclusion: Based on this findings, botanicals can be used in preserving cowpeas instead of using synthetic insecticides that are highly toxic and their use has some negative consequences on human, animals and the environment.