|Anaerobic soil disinfestation disease control performance in strawberry as influenced by environmental variables|
S. S. HEWAVITHARANA (1), C. Shennan (2), J. Muramoto (2), M. Mazzola (3). (1) Washington State University, Wenatchee, WA, U.S.A.; (2) University of California-Santa Cruz, Santa Cruz, CA, U.S.A.; (3) USDA ARS, Wenatchee, WA, U.S.A.
Sustainability of the California strawberry industry is challenged by soil-borne diseases caused by <i>Fusarium oxysporum </i>(Fo), <i>Macrophomina phaseolina </i>(Mp) and <i>Verticillium dahliae </i>(Vd). Anaerobic soil disinfestation (ASD) has been studied as a non-fumigant measure for control of these diseases. This study examined relationships between ASD temperature and duration, and ensuing levels of disease control and plant growth performance. Soils naturally infested with one of the three pathogens were subjected to ASD using rice bran under four temperature regimes of 3 or 6 week duration. Soils were planted with strawberry and grown in the greenhouse for 3-5 months. Wilt scores, cumulative yield, fresh total/shoot/root biomass (TB/SB/RB), and percent crown infection (PCI) were obtained at harvest. ASD reduced soil density and wilt score of Fo, Mp and Vd. Significantly higher cumulative yields were obtained in Fo and Vd soils in response to ASD, with duration of the ASD treatment affecting suppression of Vd. ASD treatment resulted in significantly higher TB in Fo infested soil. ASD significantly improved SB and RB in Mp and Vd infested soils. Incubation temperature only influenced SB in Vd soil. Efficacy of ASD, as assessed by PCI, was influenced by incubation temperature for Fo and Mp, and by duration for Mp and Vd. Knowledge of how these environmental variables alter ASD efficacy is required to optimize its implementation for control of soil-borne strawberry diseases.