A new approach for strawberry disease control

Authors: Takeda, Fumiomi; Janisiewicz, Wojciech; Smith, Barbara; Evans, Breyn

Submitted to: European Journal of Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2018
Publication Date: 2/14/2019
Citation: Takeda, F., Janisiewicz, W.J., Smith, B.J., Evans, B.E. 2019. A new approach for strawberry disease control. European Journal of Horticultural Science. 84(1):3-13. https://doi.org/10.17660/eJHS.2019/84.1.1.
DOI: https://doi.org/10.17660/eJHS.2019/84.1.1

Interpretive Summary: Fungicides are used to control diseases; however, several major strawberry pathogens have developed resistance to fungicides. Previously, UV-B and UV-C irradiation treatments of strawberries were reported to be not effective and often damaging to plants at the doses required to kill or reduce pathogens to achieve disease control. In our research, UV-C irradiation treatment was followed by a dark period which controlled fungi that cause anthracnose disease at reduced irradiation doses. Further, applications of microbial antagonists that are good colonizers of strawberry plants in combination with UV-C treatment reduced recolonization of strawberry leaves and fruit by fungi several days after application of UV-C treatment and microbial antagonists. The combined treatment of microbial antagonists to replenish the "microbial vacuum" after UV-C irradiation may allow for reduced frequency of irradiation, and make the system more robust and reduce the amount of fungicides needed to control diseases.

Technical Abstract: Here, we report a new approach demonstrating the killing power of UV-C treatment against fungal pathogens without damaging strawberry plants. UV-C light was followed by a specific dark period. Field trials also included applications of microbial antagonists twice a week. The dark period most likely prevented activation of the light-induced DNA repair mechanism in microorganisms and greatly increased the lethality of the UV-C. This approach allowed for a substantial reduction of the UV-C effective dose to kill the microorganisms on leaves, flowers and fruit, without damaging the strawberry plant. The application of microbial antagonists resulted in excellent colonization of strawberry plants which filled the microbial void after UV-C "sterilization" and provided a barrier for recolonization by plant and potential foodborne pathogens.