Adaptation of soil solarization to the integrated management of soilborne pests of tomato under humid conditions.

ABSTRACT Soil solarization was shown to be cost effective, compatible with other pest management tactics, readily integrated into standard production systems, and a valid alternative to preplant fumigation with methyl bromide under the tested conditions. Solarization using clear, photoselective, or gas-impermeable plastic was evaluated in combination with metham sodium, 1,3-dichloropropene + chloropicrin, methyl bromide + chloropicrin, pebulate, or cabbage residue. Strip solarization, applied to 20-cm-high, 0.9-m-wide beds, was conducted to achieve compatibility with standard production practices and resulted in soil temperatures 2 to 4 degrees C above those temperatures resulting when using conventional flatbed solarization. Soil temperatures were 1 to 2 degrees C higher at the edges of the raised beds, eliminating any border effects associated with solarization. Following a 40- to 55-day solarization period, the plastic was painted white and used as a production mulch for a subsequent tomato crop. The incidence of Southern blight and the density of Paratrichodorus minor and Criconemella spp. were lower (P < 0.05) in solarized plots. No differences (P < 0.05) in the incidence of Fusarium wilt and the density of nutsedge and Helicotylenchus spp. were observed between plots receiving solarization and plots fumigated with a mixture of methyl bromide + chloropicrin. The severity of root galling was lower (P < 0.05) when soil solarization was combined with 1,3-dichloropropene + chloropicrin (16.2 + 3.4 g/m(2)) and a gas-impermeable film. The incidence of bacterial wilt was not affected by soil treatments. Marketable yields in plots using various combinations of soil solarization and other tactics were similar (P < 0.05) to yields obtained in plots fumigated with methyl bromide + chloropicrin. The results were validated in several large scale field experiments conducted by commercial growers.