Ethoprop depletion from soil as influenced by simulated rainfall

Two field microplot tests were conducted in sandy soil to evaluate retention of ethoprop in relation to simulated rainfall levels. Ethoprop was applied at the equivalent of 13.5 kg a.i./ha, and simulated rainfall was added at rates of 2.5, 7.5, 15.0, and 22.5 cm over a 6-day period. Ethoprop concentration in the soil at 5-, 10-, and 40-day intervals indicated that it was depleted rapidly with increased rainfall levels. The 2.5-cm level of simulated rainfall reduced ethoprop concentration to one-half in the 0 to 15 cm depth within 10.7 days, whereas the 22.5 cm of rain shortened this period to 1.7 days. Soil samples taken 10 days after ethoprop treatment and inoculated with Meloidogyne javanica indicated that 2.5 cm of rain rendered the nematicide ineffective against M. javanica.