Abstract:
Biossay experiments were conducted both in the laboratory and in storage to evaluate efficacy and repellent properties of two botanicals; Tephrosia vogelii Hook and Calodendrum capense Thunb dust at the rate of 0.11%, w/w and 0.22% w/w as feeding deterrents against shelled hybrid 5HB maize weevil, Prostephanus truncatus Horn. Their efficacies were compared with standard actellic super (2% dust 0.056% w/w). T. vogelii, C. capense and actellic super dust attained mean mortalities of 60%, 70% and 100% respectively on adults of P. truncatus over exposure period of 28 days .The lethal mean mortality exposure time (LT50) varied from 8-14 days for the two botanicals. The two botanicals and actellic super effectively reduced the F1 progeny by more than 60%. The former products exhibited a higher repellency against P. truncatus at lower dosages (0.11%w/w) compared to actellic super dust. The three treatments offered effective protection of shelled maize grain for the first 90 days. However, significant (P=0.05) percent weight loss was observed there after, hence requiring a repeat application after the initial 3 months.
Key words. Mortality, Calodendrum capense, Tephrosia vogelii Hook, , Prostephanus truncatus efficacy, repellency and hybrid 5HB maize.
