Repellent Effects of Selected Organic Leaf Extracts of (Hemsl.) A. Gray and (O. Hoffman) against Motschulsky (Coleoptera: Curculionidae).

INTRODUCTION

infestation is among the major setbacks to sustainable maize farming and availability. It causes an estimated annual loss of 5-10% and 20-30% of the total maize grains loss in the temperate and tropical zones, respectively. Although synthetic pesticides are quick and effective in managing crop pests, their overuse and misuse is discouraged due to their detrimental effects on human and environment. Natural pesticidal products that are extracted from plants are particularly gaining importance as an alternative to synthetic pesticides. They are available, easily biodegraded and have low toxicity to nontarget organisms. Most botanical pesticides act on insects by repelling them away from the crops in the field or in the stores. Therefore, this study aimed to determine repellency potential of organic leaf extracts of and on . . The phytochemical profile of and was determined using GC-MS. Laboratory-based experiments were carried out using area preference method to assess the efficacy of the extracts against weevils for a test period of 5 h. Six groups of experiments were set up with ten in each test: positive control (Actellic), negative control (solvent only), and four different experimental extract concentrations (25, 50, 75, and 100%).

RESULTS

The results indicated that and leaf extracts possess potent repellency effect on weevils. All the extracts simply discouraged from the treated areas recording significantly good levels of repellent activities between 26 and 96%. Furthermore, the GC-MS analysis manifested the presence of bioactive compound in the extracts which are associated with the repellency effects.

CONCLUSION

The study scientifically confirms the traditional use of the and and provides important platform for further study on the extracts as bioresource of botanical repellent.