Exploring cover crop biomass as carbon sources in anaerobic soil disinfestation to manage Agroathelia rolfsii

Authors: GARCIA-GONZALEZ, JOSE - Virginia Tech; Mehl, Hillary; LANGSTON, DAVID - Virginia Tech; REITER, MARK - Virginia Tech; STRAWN, LAURA - Virginia Tech; RIDEOUT, STEVEN - Virginia Tech

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2026
Publication Date: 5/1/2026
Citation: Garcia-Gonzalez, J.F., Mehl, H.L., Langston, D.B., Reiter, M.S., Strawn, L.K., Rideout, S.L. 2026. Exploring cover crop biomass as carbon sources in anaerobic soil disinfestation to manage Agroathelia rolfsii. HortScience. 61(5):934-942. https://doi.org/10.21273/HORTSCI19260-26.
DOI: https://doi.org/10.21273/HORTSCI19260-26

Interpretive Summary: With the phase-out of fumigants such as methyl bromide, alternative methods are needed for management of soilborne diseases in crops. Anerobic soil disinfestation (ASD), a process that consists of incorporating carbon sources such as cover crop biomass into soil then covering the soil surface with plastic to induce anerobic conditions, is a promising method for management of soilborne fungal diseases due to its impact on soil chemical and biological properties. A factor limiting the feasibility of ASD is availability of locally sourced biomass that can effectively induce anerobic soil conditions. Thus, the current study evaluated locally available carbon sources including cool-season cover crop for their potential use in ASD for vegetable production in the mid-Atlantic U.S. Though several cover crops induced desirable changes in soil chemical and biological properties as well as plant health, suppression of the soilborne fungal pathogen Sclerotium rolfsii was not documented. Results demonstrate that cool-season cover crop biomass can serve as carbon source in ASD, but further research is needed to optimize S. rolfsii control in U.S. mid-Atlantic plasticulture systems.

Technical Abstract: Although anaerobic soil disinfestation (ASD) is a promising alternative for managing soilborne pathogens in plasticulture systems, its inconsistent efficacy and high, often unavailable carbon inputs limit feasibility. In 2020, two ASD growth chamber and greenhouse experiments evaluated six cool-season cover crop biomasses and three local organic amendments to determine the effects on soil anaerobicity, viability of the soilborne fungal pathogen Agroathelia rolfsii, soil fertility, and vigor of tomato (Solanum lycopersicum L.). Field-collected soil in pots was amended with carbon sources and inoculated with A. rolfsii sclerotia, mulched with polyethylene, saturated with water, and incubated at 15 °C /25 °C (12/12 hours) for 3 weeks. All carbon sources, except wood biochar and mushroom compost, induced anaerobic conditions. However, sclerotial viability was not reduced and decreased sclerotial colonization by Trichoderma sp. compared with the nonamended aerobic control. All carbon sources, except wheat and biochar, induced greater soil microbial activity compared with the nonamended control, with poultry litter showing the greater effect. Soil pH was generally increased by ASD treatments. Soil nitrate accumulation after ASD varied, but mushroom compost, poultry litter, Austrian winter pea, and spring oat increased nitrate concentrations in at least one experiment compared with nonamended aerobic control. Poultry litter, followed by Austrian winter pea, resulted in the greatest total fruit weight and shoot dry biomass, and both responses were positively associated with the effect of ASD on soil nitrate. The results demonstrate that cool-season cover crop biomass can serve as carbon source in ASD; however, further research is needed to optimize A. rolfsii control in mid-Atlantic US plasticulture systems. Because these experiments were performed under controlled conditions, field responses may vary; however, the findings provide references for field evaluations of cover crop-based ASD systems in the mid-Atlantic United States.