Abstract
A three year-experiment was conducted at two locations near Homestead, Florida to evaluate the feasibility of using a biologically-based system for winter production of freshmarket tomatoes (Lycopersicon esculentum Mill.) in south Florida fields with light to moderate infestations of the rootknot nematode (Meloidogyne incognita [(Kofoid and White) Chitwood], and yellow nutsedge (Cyperus esculentus L.). The system consisted of a cropping rotation in which nematoderesistant cover crops [cowpea (Vigna unguiculata (l.) Walp. cv. Iron Clay), velvetbean (Mucuna deeringiana (Bort.), Merr.) and sunn hemp (Crotalaria juncea L. cv. Tropic Sun)] were followed by a nematode-resistant tomato (Lycopersicon esculentum Mill.) crop. There were two cover crop treatments (cowpea and velvetbean) and a standard methyl bromide/chloropicrin (MC-33) treatment in 2000/01. A third cover crop treatment using sunn hemp was added in 2001/02. In 2003/04, two cover crop treatments (velvetbean and sunn hemp), a fallow (no cover crop), and a MC-33 treatment preceded by a summer sorghum sudangrass cover crop were used. Biomass production by the velvetbean, cowpea, and sunn hemp crops averaged 14.8, 8.5, and 11.6 Mg·ha[sup-], respectively. Suppression of root-knot nematode (Meloidogyne incognita) by the cover crops could not be rigorously determined because of very low or low density nematode populations. Marketable tomato yields in all treatments and in all years were above average annual yields in Miami-Dade County. Yields were highest in 2003/04 because the crop was healthy and favorable prices encouraged eight harvests. In contrast, yields were low in 2001/02 due to a heavy infection by foliar pathogens. In 2000/01, there was no significant difference in extra-large fruit yield among the treatments but the MC-33 treatment had a higher yield of large fruits than the cowpea and velvetbean treatments, thus resulting in a higher total marketable yield than both cover crop treatments.
