Technical Abstract: Propargyl Bromide (PrBr) is a promising alternative fumigant that has not been studied for nearly 50 years. In 1999 USDA initiated research to evaluate PrBr as a MeBr alternative. The research involves scientists from USDA-ARS in Calif. and Florida, Univ. of Calif., Univ. of Florida, and USDA-IR-4 to evaluate efficacy of PrBr against selected pathogens and pests and the response of several crops. Preliminary field efficacy trials carried out in 2000 included small plot studies on strawberry, tomato, carrot, and grape nursery, and microplot studies of tomato and flowers. These initial studies indicated good efficacy against soil pathogens at rates about 1/4 to 1/2 those presently used with MeBr. Initial studies have also been completed on the chemical characteristics of PrBr, its degradation in the soil, and transport through plastic films. In those initial field studies, a toluene e(20%) formulation of PrBr was used. The field and microplot studies are being repeated this year with a new formulation with inert stabilizers. We will determine yield and quality of production, safe plant back times (phytotoxicity), and efficacy against the relevant pests and pathogens. Applications have been made by both shank and drip irrigation. Additional studies underway will determine dose response against target pests and soil distribution of fumigants under field conditions.