Suppression of Seed Beetle (Callosobruchus maculatus) Population with Root Bark Powder of Zanthoxylum Zanthoxyloides (Lam.) Waterm. (Rutaceae) on Cowpea (Vigna unguiculata (L.) Walp

Abstract

In view of the recently increased interest in developing botanical pesticides as an alternative to synthetic pesticides, this investigation was carried out to examine the insecticidal po tentials of the Zanthoxylum Zanthoxyloides (Lam.) Waterm. (Rutaceae) Root Bark Powder against Seed Beetle, Callosobruchus maculatus (F.). The experiment was carried out at ambient temperature of 28±30C and relative humidity of 68±3% in the laboratory. Population suppression activities of Z. zanthoxyloides Root Bark Powder against Seed Beetle was recorded at 5, 7 and 10 g/150 g cowpea grains laid out in completely randomized design replicated four times including the untreated control. Plant products applied at rates greater than 20% of the grain weight would not be economically viable in suppressing the population of insect pests. The root bark powder was applied to assess contact adult mortality, adult emergence, percentage weight loss and percentage grains damaged. Application rates of Z. zanthoxyloides were found to possess insecticidal activity against adult seed beetle. Topical application of the root bark powder caused significant (P<0.05) increase in adult mortality, reduced adult emergence, reduced weight loss of the grains and offered protection of cowpea grains against damage in small scale storage. Highest rate of treatment significantly increased adult mortality of C. maculatus compared to lower rates at 2 DAT. From the results, it could be concluded that the adults of C. maculatus were susceptible to Z. zanthoxyloides root bark powder. On the whole application of the plant material was better than no treatment at all. Such findings would be helpful in promoting research aimed at the development of new agents for C. maculatus control. The plant powder could also, be incorporated in Integrated Pest Management approach against C. maculatus in storage.

Keywords: Beetle, Coleoptera, Emergence, Plant Material, Powder, Survival