Joseph W. Noling

Validation of 1,3-dichloropropene plus chloropicrin broadcast application in tomato grower fields

ABSTRACT There is a need to test the efficacy of weed control technologies on a commercial scale. Therefore, large-plot field studies were conducted on tomato (Lycopersicon esculentum Mill.) farms during 1999 and 2000 to compare the effect of 1,3-dichloropropene + chloropicrin (1,3-D + Pic) application methods on rootknot nematode (Meloidogyne spp.), nutsedge (Cyperus spp.) populations, and tomato growth and fruit yield. Treatments were 1,3-D + Pic (65:35 v/v) applied broadcast at 250 L.ha−1; 1,3-D + Pic (65:35 v/v) applied in-bed at 330 L.ha−1; and methyl bromide (MBr) + Pic (67:33 v/v) applied in-bed at 350 kg.ha−1. Both 1,3-D + Pic treatments received a broadcast application of the herbicide pebulate at a rate of 4 kg.ha−1 before fumigant injection. The results indicated that MBr + Pic and 1,3-D + Pic applied in-bed + pebulate resulted in the lowest rootknot counts, with nearly three times less nematodes than treatment with 1,3-D + Pic applied broadcast + pebulate. However, there were no differences among the treatments for nutsedge density, tomato plant height and vigor, and marketable and non-marketable fruit weight. This finding indicated that by applying 1,3-D + Pic broadcast, it is possible to reduce fumigant rates and personnel poisoning risks and maintain the same tomato yield, and nutsedge and rootknot nematode control as with MBr + Pic.