EFFECT OF PLANTING TIME AND STORAGE METHODS ON GRAIN WEEVILS, SITOPHILUS SPP (COLEOPTERA: CURCULIONIDAE) INFESTING WHEAT GRAINS

Abstract

This research was conducted at special farms in Shebin Elkom locality to study the effect of planting wheat at five times (Oct. 30, Nov. 10, Nov. 16, Nov. 20, Nov. 26, 2012 ) and harvested at four times ( Apr. 4, Apr. 19, Apr. 22, Apr. 29, 2013) on the infestation of the grain weevils, Sitophilus spp, (Coleoptera: Curculionidae, along one year of storing at five tools (Metal silos, Mud silos, Polyethylene bags, Jute bags, Plastic fiber bags). Wheat grain samples (100 g) of each store model of stored grains were examined by eye and with the aid of handle lens (6 x) to calculate the average number of weevil insects per 100 g. Treatments were replicated three times. Statistical analysis of the obtained results indicated that there were significant differences in the annual weevil numbers among the planting times, the best planting time is 20 November because it has the lowest infestation numbers of weevil insects recording 4103 weevil / 100 g wheat grains, while the highest weevil numbers was recorded with the planting time 10 November giving 15796 weevil / 100 g wheat grains. Regarding to the storing tools, results indicated that there were significant differences in the annual weevil numbers between plastic fiber bags and all other tools recording the lowest numbers of grain weevil insects 5495 individual / 100 g. The highest annual numbers of grain weevils recorded in mud silos and polyethylene bags (10082- 10584 weevil / 100 g) respectively. From the obtained results it could be concluded that the suitable planting time to cultivate wheat is 20 November which resulted the lowest numbers of weevil insects, as well as the suitable tool for wheat grain storing is plastic fiber bags in comparison with other tools.