Antiovipositional and Antifertility Effects of Plant Extracts against the Flour Beetles, Tribolium castaneum (Herbst) and T. confusum (J. du Val)

Abstract

Effects of petroleum ether extracts of Trichosanthes palmata seed and Zingiber cassumunar rhizome on the fecundity and fertility of two stored grain insect pests, Tribolium castaneum and Tribolium confusum have been assessed. Laboratory studies indicated that all the doses of T. palmata seed extract reduced significantly the egg laying and hatching of both the insects in comparison with the control. The mean oviposition per female for 33 days in the untreated medium were 232.05 ± 9.91 for T. castaneum and 215.00 ± 14.43 for T. confusum respectively. The mean egg laying per female at the lowest (1000ppm) and the highest (16000 ppm) doses were 130.20 ± 11.52 and 52.95 ± 13.00 for T. castaneum; and 146.75 ± 17.66 and 52.35 ± 7.68 for T. confusum respectively. The mean hatching percentage of untreated T. castaneum and T. confusum were 69.90 ± 1.73 and 65.90 ± 2.98 respectively whereas the lowest mean value was 46.10 ± 1.73 for T. castaneum and 41.55 ± 2.35 for T. confusum at the highest dose (16000 ppm). Z. cassumunar rhizome extract also showed the toxic effect to both the insect species. Here the mean egg laying of control T. castaneum and T. confusum were 216.80 ± 12.14 and 223.85 ± 13.54 respectively. The mean oviposition of treated female at 1000 and 16000ppm were 111.90 ± 4.38 and 45.20 ± 7.62 for T. castaneum; and 126.55 ± 7.44 and 54.55 ± 8.10 for T. confusum. The egg hatch at the highest dose was 48.80 for T. castaneum and 50.80 for T. confusum while the control values were 71.63 and 73.42 respectively.