Laboratory studies on vacuum and inert gas packing for the control of stored‐product insects in foodstuffs

Abstract

AbstractCowpeas, wheat flour and wheat grain infested with various developmental stages of, respectively, Callosobruchus maculatus (F) (Col: Bruchidae), Tribolium castaneum (Herbst) (Col: Tenebrionidae) and Rhyzopertha dominica (F) (Col: Bostrichidae) were packed under vacuum or in CO2 or N2atmospheres in plastic laminate pouches. After holding for up to 35 days the packs were opened and their contents incubated to allow survival to be assessed.Almost all eggs of C maculatus were killed when vacuum packed at chamber pressures of II kPa or less and held under vacuum for 14 days, whereas about 7% of young larvae survived these conditions. In contrast, R dominica was more difficult to control when packed as eggs; about 10 % and 2% of eggs laid survived to adulthood after two weeks following packing at II kPa and 0·9 kPa, respectively, whereas larvae and adults were all killed. Populations of T castaneum eggs, larvae and adults were effectively controlled by vacuum packing at 11 kPa and holding for 7 days.None of the insects tested survived being packed in a CO2 or N2atmosphere and held for periods ranging from 4 to 14 days.Many C maculatus survived vacuum and gas treatments when polyethylene film was used as packaging material. Control failures also occurred when pouches were punctured either by the commodity or by insects.