Digging Up The Dirt on Cranberry Field Decline

When it comes to climate, soil conditions and production systems, BC’s cranberry beds are unique compared to other growing regions. Unfortunately, this means that many of the challenges producers face are similarly distinct, sometimes posing unprecedented dilemmas that elude existing resources.

So, when several fields across BC were struck by “Cranberry Field Decline” (CFD), where patches of vines can no longer produce crops and eventually die, there were no tools available to identify at-risk fields, recommendations for prevention, or treatment options for affected fields suffering the devastating impacts on productivity.

And while it became clear that incidents of CFD were increasing, the cases still appeared random with no obvious reason or pattern to the outbreaks observed in different beds. 

“There are fields where one exhibits extreme CFD symptoms while adjacent fields show no indication of symptoms whatsoever,” says Jack Brown, chair of the BC Cranberry Marketing Commission. “There was no apparent cause, so we couldn’t formulate a solution.”

With funding from the governments of Canada and British Columbia through the Growing Forward 2 Canada-BC Agri-Innovation Program, the Commission undertook a three-year project to find answers that would not only enable them to deal with CFD, but to also gain a deeper understanding of BC’s unique production system.

Researchers began by mapping the distribution of CFD over the past ten years in BC cranberry beds and conducting field trials on six local farms. After extensively analyzing the physiological plant and soil characteristics associated with the symptoms, they were able to identify one possible cause and develop diagnostic tools and potential management strategies to prevent, manage and treat CFD.

According to the findings, the root of the problem may have been the roots themselves.

“It appears the primary culprit behind the disorder may be poor root health or ‘low rooting capacity,’” Jack explains. “As a result, plants became deficient in water and nutrients which reduced photosynthesis and carbohydrate reserves, weakening their structural integrity and causing canopy collapse.”

Initial recommendations to growers include monitoring the cranberry canopy for balanced root and shoot development and implementing management practices like sanding and/or pruning to maintain a desirable canopy architecture and rooting capacity. Researchers also developed the “Pull-Test” which provides growers with a tool to detect reduced rooting capacity and assess mature fields for their risk levels of developing CFD.

The project team also found that utilizing aerial imagery may offer growers another diagnostic tool for early detection of CFD, prior to the symptoms visually manifesting in the field.

In addition to yielding information for managing this formerly mysterious disease, Jack credits the study for contributing to broader, long-term industry benefits.

 “This project represents one of the most comprehensive physiological assessments of cranberries in BC to date,” he asserts. “We now possess valuable information that will not only help address the challenges of CFD, but will also improve cranberry production practices in general.”

Funding: $28,451 provided by the Governments of Canada and British Columbia through Growing Forward 2, a former federal-provincial-territorial initiative (INN235); and $7,790 through former federal adaptation funding.