Biopesticidal Effect of Acokanthera schimperi and Nicotiana tabacum on Maize Storage Insect, Sitophilus zeamais

Abstract

Maize serves as a primary staple food for approximately one-third of the sub-Saharan population. Despite being the third most widely produced grain globally, various factors impede its production. Insects, par ticularly maize weevils (Sitophilus zeamais), play a crucial role in hindering maize production, especially during storage. This study investigates the efficacy of two medicinal plants, Acokanthera schimperi and Nicotiana tabacum, in managing the maize weevil, a significant pest affecting stored grain. Adult maize weevils (S. zeamais) were collected and reared in the entomological laboratory at Addis Ababa University. The medicinal plants, Acokanthera schimperi and Nicotiana tabacum, were processed into powder and applied to the laboratory-reared S. zeamais in varying amounts. Statistical analysis, using SPSS version 16’s ANOVA, was conducted to assess mean differences among replicates and dose rates. The plant toxicity test employed the "corrected mortality (%)" formula. Results indicated that Nicotiana tabacum demonstrated effectiveness against the maize weevil, with approximately 59% mortality recorded among adult weevils during the experimentation. This highlights the potential for sustainable utilization of plant resources for affordable pest management, while simultaneously mitigating the environmental detriments associated with conventional methods.