THE EFFECT OF THE INFESTATION WITH THREE SITOPHILUS SPECIES ON THE WEIGHTS OF GRAINS STORED UNDER LABORATORY CONDITIONS FOR ONE YEAR

This article aimed to study the effect of the infestation of Sitophilus species on the average weights of wheat, maize, and rice grains stored under laboratory conditions for one year. The average weights of grains were gradually decreased along year months from 10 kg reaching 7 kg at the end of the experiment. The wheat weevil, Sitophilus granarius insects appeared in the wheat grains at the second month of storage with a few numbers (1 insect / kg grains) and gradually increased along year months recording 80 insect / kg grains at the end of the experiment. The average weights of maize grains were gradually decreased along year months from 10 kg reaching 6 kg at the end of the experiment. Results also indicated that there were no damage or infestation at the first month of storing, meanwhile the damage start to increase at the third month recording 5 % , and 7 % after 4 months , and continued in increase recording 65 % after 12 months of storing . The maize weevil, Sitophilus zeamais insects appeared in the maize grains at the second month of storing with a few numbers (2 insect / kg grains) and gradually increased along year months reaching 75 insect / kg grains at the end of the experiment. The average weights of rice grains were gradually decreased along year months from 10 kg reaching 6 kg at the end of the experiment. The rice weevil, Sitophilus oryzae insects appeared in the rice grains at the second month of storing with a few numbers (2 insects / kg grains) and gradually increased along year months recording 75 insects / kg grains at the end of the experiment.