Hydrolysis and volatility contributed to loss of 14C-ring-labeled chlorpyrifos on air-dried surfaces of SOils and soil clays in the laboratory. Dissipation rates were influenced by temperature, composition of the substrate, and level of hydration. Chlorpyrifos degraded rapidly via a temperature-dependent catalytic hydrolysis process on Sultan silt loam. Times for 50% degradation at 5, 15, 25, 35, and 45°C were >20, >20, 8, 3, and 1 day, respetively, when ambient RH levels were 93, 67, 38, 30, and 10%, respectively. The insecticide degraded even more rapidly on air-dried surfaces of calcium homoionic clays (illite, vermiculite, adkaolinite) and clay separates isolated from Sultan silt loam and Chehalis clay loam. Degradation was slower on a sandy loam, on montmorillinite, and on an organic soil and negligible on pulverized peat moss and quartz sand. An increae in the sorbed water content of air-dried substrates decreased the rate of the clay-catlyzed hydrolysis reaction and increased the volatilization rate of 14C from mineral substrate surfaces. 3,5,6-trichloro-2-pyridinol was the only 14C-breakdown product found in acetone extracts of aged, chlorpyrifos-treated soils and homoionic clays.
Document Type: Research Article
Publication date: December 1, 1981
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.