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

Abstract

Belonolaimus longicaudatus and Phytophthora cactorum are pathogens threatening Florida strawberry production. The interaction among these and cultivar susceptibility were assessed in this study. Cultivars ‘Sensation® Florida127’, ‘Florida Brilliance’, ‘Florida Radiance’, ‘Winterstar™ FL 05-107’, ‘Florida Elyana’, ‘Strawberry Festival’ and ‘Florida Beauty’ were used to conduct one trial using plug transplants and a second trial using bare-root transplants, which was repeated twice. A factorial combination of P. cactorum (+/−) and B. longicaudatus (+/−) inoculation was applied to evaluate strawberry cultivar resistance to P. cactorum and B. longicaudatus as well as their interaction. The effect of P. cactorum on the canopy, root length, and root and shoot weight was dependent on cultivars. For the plug transplant trial, the overall average of plant mortality among all tested strawberry cultivars was 0.1%, suggesting higher tolerance against P. cactorum when vigorous transplants were used. Conversely, the repeated bare-root transplant trial demonstrated different levels of susceptibility in strawberry cultivars when transplants were inoculated with P. cactorum. ‘Sweet Sensation’ ‘Florida127’, ‘Florida Brilliance’, ‘Florida Radiance’ and ‘Winterstar FL 05-107’ were highly susceptible, whereas ‘Florida Elyana’ and ‘Strawberry Festival’ were resistant. Moreover, ‘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 an antagonistic interaction between the pathogens. None of the cultivars was tolerant to B. longicaudatus as this nematode reproduced from 13.4- to 23.8-fold and caused root damage under glasshouse conditions.