Effects of nitrogen and phosphine mixtures on storedproduct insects’ mortality

Abstract

A study to determine the effect of nitrogen mixed with phosphine on controlling stored-grain insects was conducted in the storehouse. Adults of Sitophilus oryzae (L.), Tribolium castaneum (Herbst), Rhizopertha dominica (F.), Callosobrochus maculatus (F.) and 3th larvae of Plodia interpunctella (Hubner) were exposed the mixture of nitrogen and phosphine. After exposure periods of 24 h, the insects were transferred to clean jars containing food and held at 27±2°C and 65 ±5% R H. Experiments were performed in different heights (30, 35, 40, 45 and 100 cm) and nutrition materials (rice, wheat and date), in penetration tests and empty-space tests. In empty-space trials, the highest mortality was for S. oryzae and P. interpunctella. In the penetration tests, treatment with high-pressure nitrogen and phosphine under different height and foodstuff resulted in different rates of mortality. The mixture of nitrogen and phosphine in the interaction between height and diet (height × diet) was not significant for T. castaneum, R. dominica, C. maculatus and P. interpunctella, but for S. oryzae, it was significant. The influence of nitrogen gas and phosphine in the date was more than it was in rice and  wheat. The mixture of nitrogen with phosphine can be a suitable fumigant for decreasing phosphine under ambient storage conditions in penetration and empty-space fumigations.

Key words: Fumigant, Insect, nitrogen, phosphine, Sitophilus oryzae, Tribolium castaneum, Rhizopertha dominica, Callosobrochus maculatus, Plodia interpunctella.