The potency of six medicinal plant extracts against the stored grain insect pest Sitophilus granarius L.

Abstract EN

This study was conducted on six medicinal plants viz., Vitex negundo (leaves), Xanthium strumarium, Caesalpinia bonduc, Mucuna pruriens, Moringa oleifera (seed kernels), Tagetes erecta (petals) for their bio-insecticidal activity.

The powders of various parts of plants were extracted using the MARS6 microwave acid digestion system.

Three different concentrations (20, 30, and 40%) of plant extracts were tested against granary weevil, Sitophilus granarius L.

(Coleoptera: Curculionidae) for their bio-insecticidal activities under laboratory conditions.

The results of statistical analysis showed a good performance of all plant extracts, especially at the high concentrations of the extracts, where they showed different levels of insect mortality and their developmental rate was also reduced leading to significant reduction in insect numbers.

The mortality rate ranged was 0-100% with S.

granarius adults (p < 0.01).

There was significant correlation (R=1) between mortality rate and the concentration of plant extracts.

However, the extract of Mucuna pruriens with solvents (Acetone + Petroleum Ether) showed the highest mortality rate of 100% at the three concentrations used (p < 0.01), whereas, the lowest average mortality of 43.3% (p < 0.01) was observed with Xanthium strumarium and Vitex negundo extracts with solvents (Methanol + n-Hexane) compared with 0% mortality in the control.

All plant extracts have revealed insecticidal as well as propitious protective effect on grains, and it can be selected as effective control treatment after proper dose formulation to prevent weevil infestation in stored grains.