Location: Crop Improvement and Protection ResearchTitle: Status of Macrophomina phaseolina on strawberry in California and preliminary characterization of the pathogen Author
Submitted to: International Journal of Fruit Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2016
Publication Date: 7/20/2016
Citation: Koike, S., Arias De Ares, R.S., Hogan, C.S., Martin, F.N., Gordon, T. 2016. Status of Macrophomina phaseolina on strawberry in California and preliminary characterization of the pathogen. International Journal of Fruit Science. doi: 10.1080/15538362.2016.1195313. Interpretive Summary: This manuscript describes the current status of the research on an emerging pathogen that has become a serious threat to California strawberry production with the phase out of historical methods of preplant soil fumigation. The pathogen is called Macrophomina phaseolina, which normally has a broad host range but the strains infecting strawberry appear to be host specific. In examining the genetic background of isolates recovered from a range of plants in California the strawberry isolates form their own distinct grouping.
Technical Abstract: Macrophomina crown and root rot has become a significant soilborne disease issue in California. For many locations in the state, the disease is associated with fields that are no longer pre-plant, flat field fumigated with methyl bromide + chloropicrin. Inoculation experiments indicated that some differences in strawberry cultivar susceptibility to Macrophomina phaseolina were seen a short time after the inoculation but that as disease progressed such differences did not persist. Preliminary characterization studies of M. phaseolina isolates from strawberry indicated that such isolates may have a host preference for strawberry. M. phaseolina isolates from watermelon, thyme, and apple failed to cause disease in strawberry. Five cover crop species, which can be rotated with strawberry, did not develop disease when inoculated with strawberry isolates. Using SSR marker analysis, the strawberry isolates formed a separate group compared to isolates recovered from other known M. phaseolina hosts.