Potential synergism of diatomaceous earth and Piper guineense for management of Callosobruchus maculatus in stored cowpea

Abstract

Some biological effects of SILICO SEC powder [diatomaceous earth (DE)] formulation and Piper guineense seed powder against the cowpea seed beetle, Callosobruchus maculatus F. were investigated under laboratory conditions at University of Port Harcourt, Nigeria. SILICO SEC and P. guineense powder were used to treat infested cowpea seeds in a small transparent plastic container at 0.02, 0.04, 0.06, 0.08 g/20g of seed. Number of eggs, adult progeny development, and adult mortality were the biological effects measured. All the application rates of the diatomaceous earth produced significant mortality of C. maculatus 24 hours (85.6-90.0%); and 48 hours (100.0%) post-treatment compared with the control. All the application rates of seed powder of P. guineense produced significant mortality of C. maculatus 24 hours (65.0-70.0%); and 48 hours (99.6%) post-treatment with the control. Binary mixture of P. guineense seed powder and DE significantly reduced oviposition and progeny by the beetle in comparison with the control. The result further indicated the potential of combining P. guineense seed powder and SILICO SEC for increased biological effects against C. maculatus infesting cowpea seeds in storage.