Variation of Corn Weevil Sitophilus Zeamais Population in a Hermetic Preservation Minienvironment Depleted of Oxygen

The growth of a corn weevil SITOPHILUS ZEAMAIS was studied in the weevils culture and maize storage minienvironment, with diferent oxygen concentrations ranging from 0 %, 5 % 10 % 15 % oxygen, and in the control environment with 21 % oxygen. In the weevils culture ME with 21 % oxygen the maize weevils SITOPHILUS ZEAMAIS normally growth and there was no dead weevil during the 80 days of experiment, and the percentage loss of corn weight was over 29 %. However, under the same experimental conditions, with a lower oxygen concentration, of 15 %, 10 % and 5 %, the number of weevils appeared decreased and the number of dead weevils increased, and the weight loss rate of maize significantly decreased, relatively as a function of the oxygen concentration. In ME at 5 % oxygen, after 80 testing days there were 90 weevils appeared, however of which 60 was died, accounting for 67 %; in comparison with that at 21 % oxygen there were 576 weevils appeared but no death one; the maize weight loss was 5.50 %, equal to about only 1/6 of that at 21 % oxygen. It was found that, in the test fram, the lower the oxygen concentration in the ME, the lower the number of weevils appeared, the larger the number of death weavils, and the greater the reducing ratio of maize mass loss. In ME with 0 % oxygen concentration there was not any weevil appeared and the corn weight loss ratio was just 0 %.