| 1,3-Dichloropropene (1,3-D) has been used for many years in Florida to manage plant-parasitic nematodes on many crops. 1,3-Dichloropropene is a fumigant nematicide available to growers and it will likely be among the most important alternative replacements for methyl bromide, which is proposed for complete phase-out in 2005. Rate, application depth, method of application, abiotic degradation, and microbial degradation are all factors that contribute to the performance of 1,3-D. Experiments were conducted in the field, microplots, and greenhouse with the goal to improve knowledge of the relative performance of 1,3-D in Florida deep sandy soils and soils capable of microbial degradation of 1,3-D at an accelerated rate (enhanced soil). Field and greenhouse experiments were performed with soil infested with root-knot nematodes enhanced for degrading 1,3-D. The number of second-stage juveniles (J2) that penetrated tomato seedlings that were transplanted into fumigated soil were evaluated to determine the efficacy of 1,3-D against root-knot nematodes in enhanced and nonenhanced soils. There were no differences in the number of J2 that entered the roots grown in fumigated enhanced and nonenhanced soils. No decrease in efficacy of 1,3-D could be detected. Field studies were performed to determine efficacious rates and methods of applications for plant-parasitic nematode control in deep sandy soils. Rates tested included 56, 84, 112, and 168 liters/ha of 1,3-D applied broadcast with conventional chisels followed by disking. Soil fumigated with 1,3-D at broadcast rates of 84, 112, and 168 liters/ha offered the best control of root-knot nematodes on squash, whereas 56 liters of 1,3-D/ha provided marginal control. Methods tested included in-row and broadcast fumigation of 1,3-D using conventional and parachisels followed by disking and subsurface hooded chisels. Number and yield, plant-parasitic nematode population density, root-knot nematodes gall indicies were determined. The highest number of fruit were from plots treated with 1,3-D applied broadcast followed by disking ( P < 0.1). The highest yield was from plots fumigated with 1,3-D applied in row with conventional chisels followed by disking (P < 0.1). At midseason and at harvest, the number of J2 was lower in all fumigated plots except in 1,3-D applied in row with parachisels and the untreated control (P < 0.1). The performance of 1,3-D applied by subsurface hooded sweep chisels was poor. Fumigation with 1,3-D, regardless of rate or methods, resulted in a decrease in root-knot nematodes that infected indicator crops. |
