Assessment of Piper guineense Seed Crude Flavonoids for Attractant Activity Using Prostephanus truncatus (Larger Grain Borer)

Background: There are increasing needs for natural ways to control the population of larger grain borer (LGB), since the use of synthetic pesticides has resulted to disastrous effects on both the environment and non-target organisms. This has been a major concern to chemical ecologists for the past years.

Objective: This work seeks to determine whether LGB, a storage pest of Zea maize, Manihot esculenta and Theobroma cacao is attracted to Piper guineense seed crude flavonoids or not. If LGB is attracted to crude flavonoids of P. guineense seeds, then crude flavonoids could be used in baited traps to control or manage the population of LGBs.

Method: Bound and sugar free flavonoids were extracted from Piper guineense seeds by treating powdered seeds in methanol (80%), n-hexane to eliminate fatty components, and dissolving in diethyl ether-ethyl acetate solvent blend (1:1), followed by refluxing ethyl acetate fraction in sulphuric acid (7%). Concentrations of bound and sugar free flavonoids, lemon juice and blends (0.0, 0.1, 0.4, 1.0, and 1.4% w/w) were analyzed for attractant activity in a Y-glass tube experiment.

Results and Conclusion: Bound and sugar free flavonoids attracted LGBs, revealing potentials of attractants, and could be used in baited traps to control or manage the population of LGBs. Lemon juice antagonized the attractant activity of both bound and sugar free flavonoids.