Toxicity of Propylene Oxide at Low Pressure Against Life Stages of Four Species of Stored Product Insects
ALI A. ISIKBER,1 SHLOMO NAVARRO,2 SIMCHA FINKELMAN,2 MIRIAM RINDNER,2 AVI AZRIELI,2 AND REFAEL DIAS2
J. Econ. Entomol. 97(2): 281-285 (2004)
Abstract: The relative toxicity of propylene oxide (PPO) at a low pressure of 100 mm Hg to four species of stored product insect at 30°C over a 4-h exposure period was investigated. PPO at 100 mm Hg was toxic to all four species tested: Tribolium castaneum (Herbst), Plodia interpunctella (Hübner), Ephestia cautella (Wlk.), and Oryzaephilus surinamensis (L.). There were differences in susceptibility between the life stages of the tested insect species. Mortality tests on all life stages of the insects resulted in LD99 values ranging from 4.7 to 26.1 mg/liter. The pupal stage of E. cautella, O. surinamensis, and T. castaneum was the most tolerant stage with LD99 values of 14.4, 26.1, and 25.7 mg/liter, respectively. For P. interpunctella, the egg stage was most tolerant, with a LD99 value of 15.3 mg/liter. Generally,PPOat 100mmHg was more toxic to P. interpunctella and E. cautella than to O. surinamensis and T. castaneum. A 99% mortality of all life stages of the tested species was achieved at a concentrations × time product of 104.4 mg h/liter. These Þndings indicate that a combination of PPO with low pressure can render the fumigant a potential alternative to methyl bromide for rapid disinfestation of commodities.
Key words: propylene oxide, Tribolium castaneum, Plodia interpunctella, Ephestia cautella, Oryzaephlius surinamensis
