Hermetic storage system preventing the proliferation of Prostephanus truncatus Horn and storage fungi in maize with different moisture contents

Grain of maize, infested as well as uninfested with Prostephanus truncatus Horn, was stored for 15 days at 27 °C under hermetic and non-hermetic conditions. Grain moisture content (m.c.) was adjusted to 14, 15, 16 and 17%. Under hermetic conditions at 3 days storage, oxygen levels were 0.8, 0. 6, 0.4 and 0.0% in grain with 14, 15, 16 and 17% m.c., respectively. However, at 6, 9, 12 and 15 days, the oxygen level dropped to 0% in all tested m.c. Insect mortality at 3 days storage under hermetic storage conditions ranged from 5 to 30%. At 6 days, insect mortality was 100% in maize with 14, 15 and 17% m.c. and 95% in grain with 16% m.c.; however, at 9 days of this m.c., mortality was 100%. In open storage, during the whole storage period and under all m.c. tested, P. truncatus manifested 0% mortality. The predominant fungus was Aspergillus ruber. The presence of this fungus was directly related to the m.c. and length of storage. Under hermetic conditions, in all m. c, the percentage of grain invaded by A. ruber ranged from 1 to 3%. In the open system, grain with 14 and 15% m.c. manifested low (1%) and moderate (13%) fungal invasion, respectively. However, at 16 and 17% m.c., the grain became strongly infested at 9, 12 and 15 days (61–97% infection). The reduction in grain germination was similar in both storage systems for all grain m.c., except for 17% at 12 and 15 days, since under hermetic conditions grain germination rates were higher than in the open system. Hermetic storage is an effective low cost-effective system for grain produced in the rural areas of developing countries.