Fall Fumigation of Potato with 1,3-Dichloropropene: Efficacy Against Pratylenchus crenatus, Yield Response, and Groundwater Contamination Potential. James B. Kotcon, Research Associate, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Rosemary Loria, Associate Professor, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Plant Dis. 71:1122-1124. Accepted for publication 21 April 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-1122.

Plots in two commercial potato fields infested with Pratylenchus crenatus were fumigated in September 1984 with 94% 1,3-dichloropropene (1,3-D) at 0, 94, 117, or 140 L of formulated material per hectare. Population densities of P. crenatus 2 wk after fumigation were reduced by all rates of 1,3-D at both locations, and up to 96% control was obtained with 140 L/ha. Yields of the potato cultivar Superior during 1985, however, were not related to mean preplant population densities of P. crenatus, which ranged from 13 to 310/100 cm³ of soil. In a separate experiment, plots in fields with shallow water tables (<4 m), were fumigated with 1,3-D (94 or 140 L of formulated material per hectare). Groundwater samples were taken from wells adjacent to fields and analyzed for 1,3-D and related hydrocarbons 1 day before, 1 wk after, and at about 3-wk intervals for 1 yr after fumigation. No detectable levels (>2 ppb) of 1,3-D or related hydrocarbons were found in ground water samples after fumigation at either 94 or 140 L/ha. About 0.6 cm of rain fell during the first 17 days after fumigation, and a total of 89.7 cm fell during the sampling period. Relatively low levels of precipitation immediately after fumigation may have reduced the potential for groundwater contamination by 1,3-D and related hydrocarbons.