On-farm evaluations of anaerobic soil disinfestation and grafting for management of a widespread soilborne disease complex in protected culture tomato production

Authors: Testen, Anna; BOSQUES MARTINEZ, MARLIA - The Ohio State University; JIMENEZ MADRID, ALEJANDRA - The Ohio State University; DEBLAIS, LOIC - The Ohio State University; TAYLOR, CHRISTOPHER - The Ohio State University; PAUL, PIERCE - The Ohio State University; MILLER, SALLY - The Ohio State University

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2020
Publication Date: 11/20/2020
Citation: Testen, A.L., Bosques Martinez, M., Jimenez Madrid, A., Deblais, L., Taylor, C.G., Paul, P.A., Miller, S.A. 2020. On-farm evaluations of anaerobic soil disinfestation and grafting for management of a widespread soilborne disease complex in protected culture tomato production. Phytopathology. https://doi.org/10.1094/PHYTO-07-20-0288-R.
DOI: https://doi.org/10.1094/PHYTO-07-20-0288-R

Interpretive Summary: Tomatoes produced in high tunnels provide income to farmers and locally produced, fresh produce to consumers. High tunnel production is threatened by four soilborne diseases: corky root rot, black dot root rot, Verticillium wilt and root knot nematodes. These diseases occur in many high tunnels in Ohio. Anaerobic soil disinfestation and grafting onto disease-resistant rootstocks were examined for managing these diseases. Anaerobic soil disinfestation consistently reduced all soilborne diseases, while grafting was most effective for reducing corky root rot severity. These two disease management tools can be applied by high tunnel growers to reduce damage to tomatoes from the soilborne disease complex.

Technical Abstract: Tomato production in Ohio protected culture systems is hindered by a soilborne disease complex consisting of corky root rot (Pyrenochaeta lycopersici), black dot root rot (Colletotrichum coccodes), Verticillium wilt (Verticillium dahliae), and root-knot (Meloidogyne hapla and M. incognita). In a survey of 71 high tunnels, C. coccodes was detected in 90% of high tunnels, while P. lycopersici (46%), V. dahliae (48%) and Meloidogyne spp. (45%) were found in nearly half of high tunnels. Anaerobic soil disinfestation (ASD) with wheat bran (20.2 Mg/ha) plus molasses (10.1 Mg/ha) and grafting onto ‘Maxifort’ or ‘Estamino’ rootstocks were evaluated in high tunnels on five farms. In post-ASD bioassays using trial soils, root and taproot rot severity were significantly reduced following ASD, and root-knot galling was also reduced by ASD. Soilborne pathogenic fungi were isolated less frequently from bioassay plants grown in ASD-treated soils than control soils. Similar results were observed in tomato plants grown in high tunnels. Soil treatment did not significantly impact yield, and grafting led to inconsistent impacts on yield. Root rot was significantly reduced by ASD in nearly all trials. Corky root rot severity was highest in non-grafted plants grown in non-treated soils, while the lowest levels of corky root rot were observed in Maxifort-grafted plants. Black dot root rot severity was higher or equivalent in grafted plants compared to non-grafted plants. Root-knot severity was lower in plants grown in ASD treated soils in high tunnels compared to plants grown in control soils, but grafting did not significantly decrease root-knot severity.