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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Publications at this Location » Publication #301102
Title: Low carbon amendment rates during anaerobic soil disinfestation (ASD) at moderate soil temperatures do not decrease viability of Sclerotinia sclerotiorum sclerotia or Fusarium root rot of common bean

Author
item BUTLER, D - University Of Tennessee
item OWNLEY, B - University Of Tennessee
item DEE, M - University Of Tennessee
item SHRESTHA, U - University Of Tennessee
item EICHLER INWOOD, S - University Of Tennessee
item MCCARTY, D - University Of Tennessee
item Burelle, Nancy
item Rosskopf, Erin

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2014
Publication Date: 6/18/2014
Citation: Butler, D.M., Ownley, B.H., Dee, M.E., Shrestha, U., Eichler Inwood, S.E., Mccarty, D.G., Burelle, N.K., Rosskopf, E.N. 2014. Low carbon amendment rates during anaerobic soil disinfestation (ASD) at moderate soil temperatures do not decrease viability of Sclerotinia sclerotiorum sclerotia or Fusarium root rot of common bean. Acta Horticulturae. 1044:203-208. doi: 10.17660/ActaHortic.2014.1044.23.

Interpretive Summary: Anaerobic soil disinfestation (ASD) is a non-chemical process which involves incorporation of a carbon source into soil followed by mulching with polyethylene film, and application of drip irrigation to saturate the topsoil or bedded area. Several mechanisms have been proposed as contributing to control of pathogens, nematodes, and weeds during ASD treatment including formation of organic acids and volatile compounds during anaerobic decomposition of the added carbon source. These mechanisms include biocontrol by microorganisms favored by ASD treatment, and changes in soil chemical constituents under anaerobic conditions. In Tennessee, growth chamber, greenhouse, and field studies have been conducted to evaluate and optimize the ASD procedure for regional production systems and to evaluate pest, soil, and crop changes resulting from differing carbon source rates and properties. A growth chamber study conducted using soil temperatures typical of spring soil treatment temperatures in this region, suggests that lower amendment rates do not consistently reduce fungal pathogen germination or growth, or disease incidence of common bean compared to an unamended control. Other preliminary work suggests that amendment rates may need to be higher for effective soil disinfestation at moderate soil temperatures. Studies to determine optimal amendment rates and properties for consistent ASD treatment at moderate soil temperatures are ongoing.

Technical Abstract: Anaerobic soil disinfestation (ASD; also termed biological soil disinfestation) is a non-chemical process which includes 1) soil incorporation of a labile carbon (C) source, 2) mulching with polyethylene film to limit gas exchange, and 3) drip irrigation to saturation of the topsoil or bedded area. A number of putative mechanisms have been proposed as contributing to control of pathogens, nematodes, and weeds during ASD treatment, although not all have been well-characterized. Mechanisms include formation of organic acids and volatile compounds during anaerobic decomposition of the added C source, biocontrol by microorganisms favored by ASD treatment, and changes in soil chemical constituents under anaerobic conditions. In Tennessee, USA, growth chamber, greenhouse, and field studies have been conducted to evaluate and optimize the ASD procedure for regional production systems and to evaluate pest, soil, and crop changes resulting from differing C source rates and properties. A growth chamber study conducted using soil temperatures typical of spring soil disinfestation treatment temperatures in this region (15 to 24°C), suggests that amendment rates less than 1 mg C g-1 soil for ASD treatment do not consistently decrease viability of Sclerotinia sclerotiorum sclerotia or decrease incidence of endemic Fusarium root rot of common bean compared to an unamended control. Variability in measures of accumulated anaerobic soil conditions and an observed soil pH increase in ASD-treated soils are also indicative of ineffective ASD treatment at low amendment rates. Other preliminary work suggests that amendment rates may need to be as high as 4 mg C g-1 soil for effective soil disinfestation at moderate soil temperatures. Studies to determine optimal amendment rates and properties for consistent ASD treatment at moderate soil temperatures are ongoing.