Rate response of 1,3-dichloropropene for nematode control in spring squash in deep sand soils

The soil fumigant 1,3-dichloropropene (1,3-D) formulated with chloropicrin is viewed as a likely alternative for replacing methyl bromide in Florida when the latter is phased out in 2005. Therefore, it behooves us to learn more about using 1,3-D in deep, sand soils. Two trials were conducted on spring squash to determine the most effective rate of 1,3-D for the control of Meloidogyne spp. Rates tested included 0, 56, 84, 112, and 168 liters/ha of 1,3-D applied broadcast with conventional chisels 30 cm deep. The chisel traces were sealed by disking immediately after fumigant application. Cucurbita pepo cv. Sunex 9602 was sown 7 days after fumigation. The population density of plant-parasitic nematodes in soil and root-knot nematode galling severity was determined at 34 and 65 days after planting (DAP), and the number of marketable fruit and yield were determined. The number of fruit and yield were higher in all plots that received 1,3-D than in untreated controls. The number of Meloidogyne spp. second-stage juveniles was lower in all fumigated plots in trial 1 at both 34 and 65 DAP, and in trial 2 at 65 DAP, than in the untreated control. The severity of root galling was decreased with all treatments in both trials, with broadcast rates of 84, 112, and 168 liters/ha providing the best control of root-knot nematodes in spring squash grown in sandy soil. Satisfactory management of root knot on squash grown in early spring months in north Florida can be achieved with low rates of 1,3-D.