A survey of cranberry fruit rots in commercial production beds in Oregon and Washington

Authors: VALENTINE, DON - Oregon State University; BOUSKA, CASSIE - Oregon State University; Stockwell, Virginia

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2024
Publication Date: 9/18/2024
Citation: Valentine, D.C., Bouska, C., Stockwell, V.O. 2024. A survey of cranberry fruit rots in commercial production beds in Oregon and Washington. Frontiers in Plant Science. 15. Article 1457320. https://doi.org/10.3389/fpls.2024.1457320.
DOI: https://doi.org/10.3389/fpls.2024.1457320

Interpretive Summary: Oregon and Washington rank in the top five cranberry producing states in the nation with a crop value >$40 million. Cranberry crop losses due to 15 different fungal fruit rot pathogens is a constant threat and growers had limited knowledge of which pathogens were present. A survey was conducted over four years to characterize the pathogen complex and document crop losses. Most of the pathogens documented in Wisconsin, Massachusetts, and New Jersey are present in Oregon and Washington cranberry beds. Losses of 5 to 40% to fruit rots in beds and up to an additional 69% loss during cold storage were recorded. Understanding who are the constituents of the pathogen complex is foundational for developing sound management practices for cranberry fruit rots.

Technical Abstract: Fungal fruit rots of cranberries are a perennial threat to the production of cranberries. Eleven genera of fungi have been reported to cause cranberry rot in the field and/or during cold storage. Oregon and Washington rank fourth and fifth in the production of cranberry in the USA, but much of the research on cranberry fruit rots has been conducted in Wisconsin, New Jersey, and Massachusetts. A survey of fungal fruit rot pathogens was conducted over four years in commercial farms in the production areas in Oregon and Washington located in the Pacific Ocean coastal zone. Yield, rot incidence, and fungal pathogens varied year-to-year. Pathogens isolated frequently from field rotted cranberries included the well-known cranberry fruit rot fungal genera from other cranberry production regions of the USA, including Colletotrichum, Coleophoma, and Physalospora. Neofabraea actinidiae, a newly-described cranberry fruit rot was consistently isolated from field-rotted fruits from beds with specific fungicide usage patterns. N. actinidiae was also one of the more significant storage rots, alongside other well established storage rots like Coleophoma and black rots. This may have important implications for Washington cranberry production, which has a large proportion of dry-harvested cranberry fields that store and sell berries unprocessed. Climatic differences among the cranberry production areas across the United States may affect the disease incidence and prevalence of different genera of cranberry fruit rot pathogens, as summer months are often much cooler and dryer than in Wisconsin and east coast states, and may also account for differing presence of various cranberry fruit rots.