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United States Department of Agriculture

Agricultural Research Service

Research Project: DOMESTIC, EXOTIC, AND EMERGING DISEASES OF CITRUS, VEGETABLES, AND ORNAMENTALS (DEED) Title: Investigating alternative strategies for managing bacterial angular leaf spot in strawberry nursery production

Authors
item Turechek, William
item Wang, S -
item Tiwari, G -
item Peres, N.A. -

Submitted to: International Journal of Fruit Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 26, 2011
Publication Date: March 12, 2012
Citation: Turechek, W., Wang, S., Tiwari, G., Peres, N. 2012. Investigating alternative strategies for managing bacterial angular leaf spot in strawberry nursery production. International Journal of Fruit Science. 60: 435-445.

Interpretive Summary: X. fragariae causes angular leaf spot (ALS) in strawberry. The pathogen is transmitted to production fields almost exclusively through infected nursery stock. A modified heat treatment has proven to be very effective at reducing systemic infections in propagation material. There are several approaches to heating plants and the method of choice, along with cultivar selection, affects the outcome. Surface-sterilizing treatments, such as dipping plants in a 10 percent chlorine bleach solution or the use of UV-C radiation, as well as a sanitation-type treatment, namely removing or trimming remnant leaf and petiole tissue from nursery-trimmed plants, can also be used to reduce the severity of ALS in the field. No one method seems to completely eliminate X. fragariae from the planting stock, but there is good indication that a strategic combination of control practices that includes heat treatment can help to reduce significantly the initial amount bacteria introduced into a field.

Technical Abstract: The focus of this article is to discuss some of the approaches we have tested for managing the bacterial pathogen Xanthomonas fragariae in infected strawberry nursery stock. X. fragariae causes angular leaf spot (ALS) in strawberry. The pathogen is transmitted to production fields almost exclusively through infected nursery stock. Of the methods that we have investigated over the past several years, a modified heat treatment has proven to be very effective at reducing systemic infections in propagation material. There are several approaches to heating plants that range in simplicity of dipping them directly into hot water baths to the use of radio frequency energy. The method of choice, along with cultivar selection, affects the outcome. Surface-sterilizing treatments also have an effect on ALS. We have tried procedures from simply dipping plants in a solution of 10% chlorine bleach to the use of UV-C radiation to reduce the severity of ALS in the field. Lastly, a sanitation-type treatment, namely removing or trimming remnant leaf and petiole tissue from nursery-trimmed plants, was found to have a significant impact on ALS. The various methods have been discussed in detail. In short, no one method seems to completely eliminate X. fragariae from the planting stock, but there is good indication that a strategic combination of control practices that includes heat treatment can help to reduce significantly the initial amount bacteria introduced into a field.

Last Modified: 10/24/2014
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