Susceptibility of seven strawberry cultivars to Belonolaimus longicaudatus and interaction with Phytophthora cactorum

Authors: OLIVEIRA, CLEMEN - University Of Florida; VAN SANTEN, EDZARD - University Of Florida; MARIN, MARCUS - University Of Florida; Schumacher, Lesley; PERES, NATALIA - University Of Florida; DESAEGER, JOHAN - University Of Florida

Submitted to: Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2023
Publication Date: 4/13/2023
Citation: Oliveira, C.J., Van Santen, E., Marin, M., Schumacher, L.A., Peres, N.A., Desaeger, J. 2023. Susceptibility of seven strawberry cultivars to Belonolaimus longicaudatus and interaction with Phytophthora cactorum. Nematology. 2023:1-12. https://doi.org/10.1163/15685411-bja10237.
DOI: https://doi.org/10.1163/15685411-bja10237

Interpretive Summary: Sting nematode and Phytophthora crown rot (a fungus) are pathogens that affect strawberry production in Florida. Yet, no studies have evaluated possible interactions between these two organisms. Seven strawberry cultivars were tested in conjunction with sting nematode and Phytophthora crown rot to determine how strawberry yield, root length, canopy, and root and shoot weight were affected. The goal was to determine if and how these two pathogens interact under greenhouse conditions to aid growers in selecting vigorous transplants for strawberry production. We showed that an antagonistic interaction occurred between the two pathogens in which the presence of Phytophthora crown rot significantly decreased the population density of sting nematode in susceptible, moderately resistant, and resistant strawberry cultivars. Vigorous transplants led to higher disease tolerance, sting nematode did not break down resistance to Phytophthora crown rot, and there was no tolerant cultivar to sting nematode. Growers can use this information in their Phytophthora and sting nematode management programs to avoid stressed transplants that lead to more plant disease.

Technical Abstract: Belonolaimus longicaudatus and Phytophthora cactorum are pathogens threatening Florida strawberry production. The interactions among these pathogens and cultivar susceptibility were assessed in this study using seven strawberry genotypes. Cultivars Sensation® Florida127, Florida Brilliance, Florida Radiance, WinterstarTM ‘FL 05-107’, Florida Elyana, Strawberry Festival, and Florida Beauty were used to conduct one trial using plug transplants and a repeated trial using bare-root transplants. A factorial combination of P. cactorum (+/-) and B. longicaudatus (+/-) inoculation was applied to evaluate if there was any strawberry cultivar resistant to P. cactorum and B. longicaudatus as well as the interaction between them. Results showed that the effect of P. cactorum on the canopy, root length, and root and shoot weight was dependent on strawberry genotype (Phyto × Cultivar, P<0.05). For the plug transplant trial, the overall average of the plant mortality among all tested strawberry cultivars was 0.1%, suggesting higher tolerance against P. cactorum when vigorous transplants were used. In contrast, the repeated bare-root transplant trial demonstrated different levels of susceptibility in strawberry cultivars when transplants were inoculated with P. cactorum. Cultivars Sweet Sensation® Florida127, Florida Brilliance, Florida Radiance, and WinterstarTM ‘FL 05-107’ were highly susceptible, whereas Florida Elyana and Strawberry Festival were resistant. Moreover, the cultivar Florida Beauty was moderately resistant to P. cactorum. Our findings demonstrated the importance of using vigorous transplants to reduce P. cactorum damage. Sting nematode reproduction was suppressed when strawberry transplants were inoculated with P. cactorum, suggesting a synergistic interaction between both pathogens. None of the cultivars were tolerant to B. longicaudatus as this nematode reproduced from 6.7 to 11.9-fold and caused plant damage under greenhouse conditions.