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

Background: Prostephanus truncatus, also called larger grain borer (LGB), is a pest of maize and
can infest field crops as well as maize in storage. 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.
Methods: 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: Crude flavonoids of Piper guineense seed can be used to control or
manage LGB infestations on maize by its application in combination with a toxicant on a non-food
crop to attract and kill LBGs. 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.