Survey of Soilborne Pathogens Infecting Strawberry in Santa Maria, California

Abstract

ABSTRACTTo determine the prevalence of the four major soilborne pathogens of strawberry in the Santa Maria growing district in California, symptomatic plant samples (n = 100) were collected from 68 fields between May and September 2022. Samples comprised 28.3% of 2021 fall-planted strawberry fields and 14.0% of 2022 summer-planted strawberry fields in the district. Recombinase polymerase amplification was used to detect Macrophomina phaseolina, Fusarium oxysporum f. sp. fragariae, Verticillium dahliae, and Phytophthora spp. in plant crown material. Macrophomina phaseolina was most prevalent, detected in 52 samples, followed by Verticillium dahliae in 17 samples, F. oxysporum f. sp. fragariae in 16 samples, and Phytophthora spp. in 14 samples. Macrophomina phaseolina was more likely in eastern field locations (P = .0159) and in instances where strawberries were planted consecutively (P = .0100). Disease incidence was more likely to be higher in samples from organic fields than conventional fields (P = .0304) and in samples from flat-fumigated fields than fields fumigated in-line (P = .0124).

Keywords

• Macrophomina root rot
• fusarium wilt
• verticillium wilt
• phytophthora crown and root rot
• root knot nematode
• meloidogyne