Pii: S0022-474x(99)00023-5

Maize grain of hybrid AN 447 was: (a) infested with Sitophilus zeamais and infected with Aspergillus chevalieri; (b) infested with S. zeamais; (c) infected with A. chevalieri; and (d) grain free of insects and fungus (control); the treatments were stored for 30 days at 268C and 15% moisture content, under hermetic and non-hermetic conditions to monitor the oxygen concentration, insect mortality, insect o€spring, grain germination, and fungal growth. The oxygen was depleted to 0% after 6±9 days in those treatments infested with insects, whereas the same oxygen level was reached after 24 days in grain with the storage fungus alone. The oxygen level gradually decreased to 8.4% after 30 days in the control treatment. All insects were dead after 6 days in grain with insects and fungus, and after 12 days in grain with insects alone. A low mortality rate (1.5±3.5%) occurred in equivalent treatments of the nonhermetic conditions. Because oxygen was depleted to 0% after 6 to 9 days in those treatments infested with insects, the weevils of both infested treatments under hermetic conditions produced a signi®cantly lower number of o€spring compared with those in the non-hermetic conditions. Under hermetic conditions in grain treated or not treated with fungicide, the storage fungus A. chevalieri invaded a low percentage of grains. A low percentage of fungal invasion occurred in grain stored under non-hermetic conditions also, where the decreased moisture content did not favor fungal growth. The grain germination of those treatments stored under hermetic conditions was signi®cantly lower than those treatments stored under non-hermetic conditions. The insects were the main oxygen consumers, followed by the fungus and ®nally by the grain. Under sealed storage conditions, insects and fungus combined forces to deplete the oxygen of hermetically stored maize, creating an unfavorable atmosphere for their own survival. # 2000 Elsevier Science Ltd. All rights reserved. Journal of Stored Products Research 36 (2000) 25±36 0022-474X/00/$ see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0022-474X(99)00023-5 www.elsevier.com/locate/jspr * Corresponding author.