Promoting Fungicide Stewardship
Gray mold, caused by the fungus Botrytis, kills blueberry flowers and rots berries resulting in reduced harvested yields and losses during storage. Currently, conventional blueberry growers follow a fungicide spray program involving rotations of several site-specific fungicides with different modes of action. However, fungicide resistance in Botrytis is a serious issue in blueberry production and has limited the effectiveness of conventional fungicide spray programs. The BPP program is generating research-based knowledge on fungicide resistance profiles of Botrytis in Washington blueberry fields, developing molecular tools to detect mutations in Botrytis that result in fungicide resistance, and determining when Botrytis infects blueberry flowers and fruit. Potential benefits of the knowledge generated are improved guidelines for gray mold management and targeted fungicide applications at an appropriate disease development stage, thereby reducing costs of chemical inputs and promoting fungicide stewardship.
Viruses Impacting Blueberry Production
Current knowledge suggests that blueberry plants can be infected simultaneously by multiple viruses, including both those that have long been recognized as present in the Pacific Northwest and newly described viruses. However, the effects of mixed virus infections, interactions with blueberry cultivars and the environment, spatial disease spread over time, symptomology, and impacts on blueberry production are largely unknown. The BPP program is using molecular methods to detect viruses such as blueberry shock virus and blueberry scorch virus and performing multi-year monitoring of blueberry fields to study temporal and spatial patterns of virus spread in blueberry fields. This research will establish the current prevalence and spread of virus infections and their potential effects on blueberry health, which will enable growers to adjust existing strategies or develop new virus management plans.
Management of Verticillium Wilt
Verticillium wilt, caused by the fungus Verticillium dahliae, is one of the most important diseases affecting potato production across the nation. Limited land availability in western Washington for the common grower practice of three-year potato crop rotations, and the presence of other crops that either do or do not host the pathogen, result in a high probability of potato being exposed to V. dahliae in soil. The BPP program is determining how host and nonhost crops affect inoculum levels, so growers can make informed decisions when selecting crops to use in rotation with potato.
Improved Molecular Methods to Detect Potato Pathogens
Currently, the potato industry lacks a unified and validated high-throughput workflow for simultaneous molecular detection of pathogens of several taxon groups (fungi, oomycetes, viruses, viroids, bacteria, and nematodes). The BPP program is leading a multistate research effort to assemble proven diagnostic technologies into a cohesive package, which will increase our nation’s capacity to respond rapidly to existing and emerging potato pathogens.