Management of Fusarium wilt of strawberry

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Crop Protection xxx (2015) 1e6

Contents lists available at ScienceDirect

Crop Protection journal homepage: www.elsevier.com/locate/cropro

Management of Fusarium wilt of strawberry Steven T. Koike a, *, Thomas R. Gordon b a b

University of California Cooperative Extension, 1432 Abbott Street, Salinas, CA 93901, USA Department of Plant Pathology, 1 Shields Avenue, University of California, Davis, CA 95616, USA

a r t i c l e i n f o

a b s t r a c t

Article history: Received 4 September 2014 Received in revised form 30 January 2015 Accepted 4 February 2015 Available online xxx

Fusarium wilt of strawberry was first described in the 1960s in Australia and Japan. Since then the pathogen, Fusarium oxysporum f. sp. fragariae (Fof), has been reported worldwide with the majority of cases being found in the 1990s and 2000s. Many of these recent reports are associated with changes in pre-plant soil fumigation practices. The disease is of significant economic importance because infected plants can collapse and die. Field diagnosis of Fusarium wilt is complicated by the fact that other soilborne diseases exhibit very similar symptoms. Methods for detection of Fof based on molecular criteria have been developed, but none have yet been shown to uniquely identify the strain of F. oxysporum causing Fusarium wilt of strawberry. Management of Fusarium wilt is best achieved through the use of resistant strawberry cultivars. Research indicates that sources of Fof resistance exist in strawberry germplasm, though cultivar reactions may differ depending on the Fof isolate. Pre-plant treatment of infested soil with fumigants remains a useful management tool. In addition, alternative treatments such as steam, solarization, anaerobic soil disinfestation, and the planting of brassicaceae crops are being assessed for their effectiveness in managing the disease. Standard integrated pest management practices of crop rotation with non-hosts, planting of pathogen-free transplants, and sanitation of equipment remain important measures that can reduce the risk of damage from Fusarium wilt. © 2015 Elsevier Ltd. All rights reserved.

Keywords: Fungi Fusarium Fusarium wilt Strawberry Fragaria

1. Introduction to Fusarium wilt Fusarium wilt of strawberry (Fragaria x ananassa) is an important disease of this crop worldwide. Caused by the pathogen Fusarium oxysporum f. sp. fragariae (Fof), the disease was first found in Australia in 1962 (Winks and Williams, 1965) and was then found in Japan in 1969 (Okamoto et al., 1970). Since that time, Fusarium wilt was confirmed on strawberry in Korea in 1982 (Kim et al., 1982), Mexico in the late 1980s-early 1990s (Castro-Franco and Davalos-Gonzalez, 1990; Cejas-Torres et al., 2008), China in 2005 (Huang et al., 2005; Zeng et al., 2006; Zhang et al., 2012; Zhao et al., 2009), the United States in 2006 (California: Koike et al., 2009) and 2011 (South Carolina: Williamson et al., 2012), Spain in 2007 (Arroyo et al., 2009), and Serbia in 2013 (Stankovic et al., 2014). In Mexico, researchers feel that Fusarium wilt is part of a disease syndrome in that the combined infections by Fof and a strawberry virus complex has contributed to the decline of strawberry in that region (Davalos-Gonzalez et al., 2014). For the more recent occurrences, Fusarium wilt outbreaks on strawberry have

* Corresponding author. E-mail address: stkoike@ucdavis.edu (S.T. Koike).

been associated with changes in pre-plant soil fumigation. In California, for example, virtually all of the initial outbreaks were associated with fields that no longer were flat-fumigated with methyl bromide þ chloropicrin that was shank injected under plastic tarps (Koike et al., 2013). Thus, the pathogen may have been present for an extended period but not detected because fumigation maintained inoculum densities below damaging levels. A preliminary assessment of California isolates of Fof has identified three somatic compatibility groups and diverse sequences in the translation elongation factor, suggesting the population is not derived from a single recent introduction (Gordon, unpublished). Consistent with the narrow host ranges of almost all formae specialis of F. oxysporum, strawberry is the only known host to Fof (Kodama, 1974). 2. Fusarium wilt symptoms In fields with no or inadequate fumigation, strawberry plants can show initial symptoms of decline as early as 30 days after transplanting; these plants will stop growing and be stunted when compared to healthy plants. However, often the initial symptoms of Fusarium wilt in strawberry occur after the plants are well established and begin to flower or produce fruit, at which time the older

http://dx.doi.org/10.1016/j.cropro.2015.02.003 0261-2194/© 2015 Elsevier Ltd. All rights reserved.

Please cite this article in press as: Koike, S.T., Gordon, T.R., Management of Fusarium wilt of strawberry, Crop Protection (2015), http://dx.doi.org/ 10.1016/j.cropro.2015.02.003


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