The Future of Hermetic Storage of Dry Grains in Tropical and Subtropical Climates
S. Navarro *, J.E. Donahaye † and S. Fishman †
*Department of Stored Products, Agricultural Research Organization. P.O. Box 6, Bel Dagan. 50250 Israel.
†Department of Statistics. Agricultural Research Organization, P.O. Box 6. Bet Dagan, 50250 Israel.
Abstract: Oxygen (0₂) depletion and carbon dioxide (C0₂) enrichment of the intergranular atmosphere fonn the basis for suppressing and controlling insect infestations during hennetic storage of dry grain. Traditional methods and recent improvements are reviewed, and modem structures designed for hennetic storage at the commercial and fanner levels are described. Improvements needed to render the hennetic concept more widely acceptable are enumerated, and the development of hennetic storage within flexible plastic liners is evaluated on the basis of more than a decade of experience in hot climates. A preliminary model is employed to simulate the interdependent changes in gas concentrations, insect populations and amounts of grain consumed. A theoretical ingress rate of 0.05% 0₂/day was found sufficient to arrest development of residual insect infestations. Potential niches for hermetic storage applications in developing and technologically advanced countries are identified. In tropical climates aeration for cooling of grain is not feasible, reinfestation is frequent and the available contact insecticides degrade rapidly because of high temperatures. The advantages of long-tenn hermetic stomge in technologically advanced countries, and as a medium-term, user-friendly technology in developing countries, are stressed. In sharp contrast to the use of chemicals, hermetic storage is environmentally sound and poses no risk to storage operators, consumers or non-target organisms.
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