Repellence of Volatiles and Extracts of Solanecio manii To Subterranean Termites, Macrotermes natalensis in Laboratory Test

Abstract

Plant based pesticides have been touted as alternatives to supplement synthetic pesticides for integrated pest management as they pose little threat to health and environment hence a need for affordable and eco-friendly alternative pesticides of botanical origin. Solanecio manii plant used traditionally by communities in Kericho to repel insects from dwellings was evaluated for repellence potential against Macroteremes natalensis termites. Samples of S. manii roots stem and leaves were collected and prepared appropriately for each test as fresh, dried or crushed forms. The dried plant parts were extracted using methanol and hexane and extracts prepared to 2, 4, 6 and 8 mg/ml dilutions respectively. Termite repellence was evaluated in a dual choice Y-tube olfactometer in a choice test and in petri dishes with inoculated paper discs (10x10) mm and rings of 10 mm width. Results indicated that on average, the highest and lowest percentages of termites contacted filter papers discs treated with pure water (23.5%) and 8mg/ml of leaves phytochemicals (2.4%) respectively. 6.6% of termites was the lowest recorded in the test compartment when fresh crushed leaves were placed in the test compartments of the Y-tube olfactometer. The average number of termites that contacted filter paper discs on repellence was significantly higher when filter paper was treated by the control than when treated with S. manii phytochemicals extracted using hexane (p < 0.001) and methanol (p < 0.001) solvents. The study concludes that S. manii extracts are potential repellents to subterranean termites authenticating and scientifically justifying traditional knowledge that exists regarding use of S. manii for termite control. Therefore, enhanced use of the plant extracts as botanical pesticide friendly to the environment is recommended.