Impact of anaerobic soil disinfestation combined with soil solarization on plant–parasitic nematodes and introduced inoculum of soilborne plant pathogens in raised-bed vegetable production

Abstract

A two-year field study was established in August 2008 at the USDA-ARS, U.S. Horticultural Research Laboratory in Fort Pierce, FL to examine the impact of anaerobic soil disinfestation (ASD) combined with soil solarization as an alternative to methyl bromide (MeBr) fumigation for control of plant–parasitic nematodes and introduced inoculum of soilborne plant pathogens. A complete factorial experiment in a split-split plot was established to evaluate three levels of applied initial irrigation (10, 5, or 0cm), two levels of partially-composted poultry litter (CPL; amended or unamended), and two levels of molasses (amended or unamended) in combination with solarization in a raised-bed bell pepper-eggplant double crop production system. Untreated and MeBr controls were established in each block for comparison to ASD treatments. Survival of Phytophthora capsici inoculum, introduced prior to ASD treatment, was equal to that with MeBr and less than the untreated control for all solarized treatments regardless of applied soil amendments during both seasons. Survival of introduced inoculum of Fusarium oxysporum f. sp. lycopersici was least (and equivalent to the MeBr control) in treatments with applied molasses during the second season. While endemic plant-parasitic nematode populations were generally low throughout the first season, by the end of the second eggplant double crop, root-knot nematode (Meloidogyne incognita) populations in treatments not receiving molasses and/or CPL (solarization only) or not receiving irrigation at treatment averaged more than 200 nematodes per 100cm3 of soil compared to an average of 10 nematodes per 100cm3 in ASD treatments where molasses or molasses+CPL was applied and irrigated with 5 or 10cm of water. Anaerobic soil disinfestation combined with solarization may provide an alternative to chemical soil fumigation for control of soilborne plant pathogens and plant–parasitic nematodes in Florida raised-bed vegetable production systems.