Qualitative Phytochemical screening of Acalypha fimbriata, and its methanol extract as protectant against Sitophilus zeamais (Coleoptera: Curculionidae) on stored maize

Abstract

Phytochemical screening of crude methanol extract of Acalypha fimbriata was done to check for presence of secondary metabolites. The result indicated that the plant contained alkaloids, tannins, saponins, flavonoids, resins and glycosides. Extracts at different concentrations of (10, 20, 30 and 40 %v/v) with a solvent-treated control (0 %v/v) were also bio-assayed for their insecticidal potential against Sitophilus zeamais on stored maize. Five pairs (1 male :1 female) of adult insects were used to infest 50 g TZPB-SR-W maize grains stored for three months. Experiment was laid out in a completely randomised design, in four replicates, in the Entomology Research Laboratory, University of Ibadan, under an ambient conditions of 27 ± 2?C and 65 ± 5% relative humidity. Parameters assessed were insect mortality, oviposition, progeny emergence as well as percentage grain damage and seed viability. Results showed that the plant extract significantly (P < 0.05) caused higher mortality, reduced oviposition, inhibited F₁ emergence and with less damage to the grains when compared to those of the control. However, insecticidal activity was concentration dependent, with 40% v/v A. fimbriata extract being the most potent. There was no significant difference (P > 0.05) in the germination of tested seeds among all treatments including the control.

Keywords:  Phytochemical screening, Acalypha fimbriata, protectant, Sitophilus zeamais