Submitted to: Crop Protection Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2012
Publication Date: March 19, 2012
Citation: Butler, D., Burelle, N.K., Muramoto, J., Shennan, C., Mccollum, T.G., Rosskopf, E.N. 2012. 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. Crop Protection Journal. 39(1):33-40. Interpretive Summary: There is a need for non-chemical options to manage weeds, soilborne plant pathogens, and plant-parasitic nematodes in vegetable production systems. This need is even greater given the global phase-out of the broad-spectrum soil fumigant methyl bromide (MeBr) as part of the Montreal Protocol, as well as the limitations of fumigant alternatives to MeBr in terms of efficacy, environmental sustainability, and human health and safety. Additionally, given the increasing demand for agricultural products produced by sustainable and organic methods, non-chemical soil management practices that are easily-adaptable for conventional, organic, or transitional systems would be widely useful to growers. The anaerobic soil disinfestation (ASD) system can be utilized in urbanized areas where fumigant buffer restrictions would limit the applicability of alternative fumigants and, unlike many other biologically-based alternatives, it has a broad-spectrum of activity, impacting most pests that are currently controlled by MeBr:chloropicrin combinations. A system was developed for Florida raised-bed production that incorporates the use of agricultural waste products that are easily accessible. The system utilized composted poultry litter and blackstrap molasses combined with soil saturation and solarization to provide soilborne fungal plant pathogen and plant pathogenic nematode control that is equivalent to that acheived with methyl bromide. The current rates of material needed to achieve efficacy with ASD may be logistically limiting to its application to small farms. Future research may enable farmers to reduce the rates of poultry litter and molasses needed on larger acreage.
Technical 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 effectiveness of anaerobic soil disinfestation (ASD) as an alternative to methyl bromide (MeBr) fumigation for control of plant pathogens and parasitic nematodes. A complete factorial experiment in a split-split plot was established to evaluate three levels of applied initial irrigation (10, 5, or 0 cm), 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. Untreated and MeBr controls were established in each block for comparison to ASD treatments. Control of Phytophthora capsici, introduced as buried inoculum prior to ASD treatment, was equal to that of MeBr and greater than the untreated control for all solarized treatments regardless of applied soil amendments during both seasons. Mortality of Fusarium oxysporum f. sp. lycopersici introduced inoculum was greatest (and greater than the MeBr standard) in treatments with applied molasses. While plant-parasitic nematode populations were generally low throughout the first season of the study, 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 100 cm3 of soil compared to an average of 10 nematodes per 100 cm3 in ASD treatments where molasses or molasses + CPL was applied and irrigated with 5 or 10 cm of water. These are promising results and ASD may provide an alternative to chemical soil fumigation for control of plant pathogens and plant-parasitic nematodes in Florida raised-bed vegetable production systems.