Biological Effect of Some Plant Extracts against Trogoderma granarium Everts

This study aimed to test the effect of aqueous extract of five plants Cuscuta chinensis Lam, Melia azedarach L., Nerium oleander L., Ricinus communis L. and Orobanche aegyptiaca Pers, at three concentrations, 2.5, 5 and 10%, as wheat grains treatment against the Khapra beetle Trogoderma granarium Everts. Results indicated that M. azedarach and N. oleander extracts had high effect on the average progeny number produced which was 13, 14.33 respectively, versus 43 in control while it was 36, 39.66 and 37.66 for C. chinensis, R. communis and O. aegyptiaca, respectively. The type of plant extract and its concentration had significant effect to the generation period loss in weight and germination of infested grains. It was also found that 80, 76.66% of larvae exposed to treated grains with plant extract of M. azedarach and N. oleander failed to complete their development to adult insect M. azedarach extract showed repellent effect to larvae when used free choice test for feeding, 5.50% of which attracted to treated wheat grains.
On the other hand the adult insects did not show Significant effect in its choice for treated wheat grains with plant extract to egg lying.