Preliminary Laboratory Evaluation of the Efficacy of Mixed Seed Powders of Piper guineense (Schum and Thonn) and Theueria penmiana (Persoon) Sebum Against CaIIosobndws .J Coleoptera: Brucbidae).

EMEASOR. K. C. EIIOSAIRUE, S. O. AND OGBWI. R. O.

ABSTRACT. The prospect of controlling the cowpea bruchid, Callosobruchus maculatus (F.), with mixture containing Piper guineense (Schum and Thonn) (Pg) ,
and Thevetia peruviana (Persoon) Schum (Tp) seed powders in the ratios of 80:20, 60:40, 50:50, 40:60 and 20:80 was evaluated under ambient laboratory conditions (28±2°C and 75±20% R H). The mixtures of seed powders (500)lm particle size) were applied at the rate of 5% of the treated seed weight. Mortality of adult insects at 2 and 7 days after infestation (DAI), number of eggs laid and number of adults that emerged from each treatment were compared with those of the controls (PgO+TpO) (Pg100+TpO), and (PgO+Tp100). All mixtures, with the exception’ of Pg 20+Tp80, significantly (P<0.05) caused higher mortality to C. maculatus than the control (PgO+TpO). The mixture Pg80+Tp20 caused the highest mortality (56.36%) at 7DAI, had the least egg count (2.34120g seed) and significantly (P<0.05) suppressed adult emergence. The seed powder mixtures did not produce additive or synergistic effect on the parameters quantified.

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