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Examining microbial mediation of disease resistance, pollinator attraction, and crop yield in apple crops

The composition of microbial communities can have dramatic, but often unappreciated, impacts on crop production. In apple crops, surveys indicate that numerous microbe species colonize flowers and nectar, which can in turn mediate floral and nectar traits and pollinator behavior. Microbial communities also affect the susceptibility of trees to pathogens such as the bacterium Erwinia amylovora, the causal agent of fire blight. For example, Blossom Protect is an organic-approved pesticide that inoculates apples with a yeast (Aureobasidium pullulans) that limits subsequent infection by Erwinia through competition. However, our prior research suggests that management of Erwinia with Blossom Protect or other strategies, including the use of antibiotics, could indirectly impact pollination in apples. This is because microbes are susceptible to many pesticides used in apples, and pollinators are sensitive to the presence of these same microbes. Yet, the extent by which microbes affect nectar traits, pollinator behavior, and resulting apple production remain untested. Moreover, the role of disease management on nectar microbe communities, and resulting impacts on pollination services, are relatively unknown. To address these knowledge gaps, we will conduct a series of objectives that examine: (1) how apple management practices influence the flower microbiome, (2) the role of different microbes on limiting infection of apples with Erwinia, and (3) the indirect effects of microbial communities and pathogen management on pollination services and apple production. Our project will broadly explore linkages between sustainable pathogen and pollination management by identifying new microbial strains that could serve as both antagonists for Erwinia and promoters of pollinator foraging behavior. These objectives align with WSU’s Sustainable Resources Grand Challenge by identifying optimal management schemes to promote production of a key agricultural crop in WA.

Grant Information

  • Project ID: 168
  • Project Status: Ongoing


  • Principal Investigator(s): Crowder, D.
  • Investigator(s): Schaeffer, R.
  • Grant Amount: $39931