Survey of Soilborne Pathogens Infecting Strawberry in Oxnard, California & Effect of Planting Date and Chill Treatment on Yield of Strawberry

Survey to quantify the frequency of the five main pathogens (Macrophomina phaseolina, Fusarium oxysporum f. sp. fragariae races 1 and 2, Verticillium dahliae, and Phytophthora spp.) infecting strawberry in the Oxnard growing district of California. M. phaseolina was the most prevalent pathogen detected in diseased plants in the Oxnard growing district, present in 67.6% of samples positive for at least one pathogen. F. oxysporum f. sp. fragariae race 1 (35.3%), V. dahlia (8.8%), F. oxysporum f. sp. fragariae race 2 (5.9%) and Phytophthora spp. (2.9%) followed at lower prevalence. Associations were found between fewer drip irrigation lines and the presence of M. phaseolina and F. oxysporum f. sp. fragariae race 2. No associations were found between pathogen presence and mulch color, organic/conventional, or soil type. To quantify the effect of planting date and chill treatment on strawberry yield, plug plants sourced from North Carolina State University were planted at Cal Poly, San Luis Obispo. Earliest planting optimized fruit yield and the number of branch crowns for both ‘Monterey’ and ‘Fronteras’ plug plants. Chilling treatment increased overall yield and number of branch crowns, and decreased plant mortality. This trial also proved the feasibility of producing high quality strawberry plug plants in North Carolina, shipping to California, and producing fruit during typical production season.