Column system for concurrent assessment of emission potential and pest control of soil fumigants

Fumigation for soilborne pest and pathogen control is under close scrutiny because of its potential hazardous effects on the environment and on human health. Therefore, reduced-risk yet effective fumigation practices are impe ratively needed. We have developed a column system that allows an integrate d evaluation of emission potential and efficacy of fumigants. The system co nsists of a large, packed soil column and a sampling chamber for measuring fumigant emissions at the soil surface. Nematodes (or of her pests) can be inoculated into the column and their survival may be assayed after the trea tment. This approach was used to evaluate the emission of 1,3-dichloroprope ne (1,3-D) and its efficacy against the citrus nematode Tylenchulus semipen etrans when ammonium thiosulfate, a 1,3-D degrading fertilizer, was applied at the soil surface. Results closely comparable to field observations were obtained. Compared with field studies, the proposed method is rapid and in expensive, and thus may be used for screening fumigation practices that hav e improved environmental safety and pest control performance.