September 08, 2025
Vancouver, BC – A Genome BC funded research collaboration between the BC Blueberry Council, Simon Fraser University (SFU) and Phyto Diagnostics Company Ltd. has uncovered why standard tests sometimes fail to detect viruses in visibly sick blueberry plants. The findings will lead to new diagnostic tools that will help protect BC’s blueberry sector that was worth $236 million in exports in 2020.
BC produces more than 90% of Canada’s highbush blueberries, a crop that in 2019 was the province’s highest-value agricultural export. Growers face two primary viral threats, the Blueberry Scorch Virus and the Blueberry Shock Virus, both of which are not harmful to people, but deal a significant economic blow to farmers.
Blueberry plants do not recover from the Scorch virus and infected plants must be removed, but they can recover from the Shock virus over time. Both viruses cause similar symptoms, making them hard to tell apart, so farmers rely on a standard diagnostic test, the ELISA (Enzyme-Linked Immunosorbent Assay) to help decide whether to rip out their plants.
But several years ago, sick plants began to test negative for both viruses.
“At the time, it was quite the black box,” said Dr. Eric Gerbrandt, the project co-lead and Research Director at the BC Blueberry Council. “We took hundreds of samples from fields in the Fraser Valley in 2020 and up to 30% of sick plant samples came back negative for the viruses that are known to affect blueberry bushes. These inconclusive results led to uncertainty for our farmers.”
To tackle the problem, the research team, led by Dr. Jim Mattsson from SFU’s Department of Biological Sciences and Dr. Gerbrandt, turned to genomic sequencing.
“These findings have a big economic impact on the sector”
The team was able to get a high-resolution view of the viral landscape afflicting blueberry plants through the sequencing of viruses from infected plant samples across BC.
“This was a complex biological puzzle that traditional diagnostic methods couldn’t solve,” said Dr. Mattsson. “By applying the power of genomic sequencing, we discovered that both the Shock and Scorch viruses had evolved into new variants, which is why the diagnostic test wasn’t successfully identifying the cause of the sick plants.”
The sequencing also revealed four new viruses, previously undetected in BC fields. The researchers determined these viruses do not cause disease in blueberry plants and so are not a threat to BC growers. “This work has vastly improved our understanding of the situation in the fields,” Dr. Mattsson added.
With the new information, the team is developing updated diagnostic tools that they expect to be available by the next growing season.
The tools include an updated ELISA test for the new viruses, as well as more sensitive PCR tests that can detect the lower virus levels of new variants of Shock and Scorch. The latter will supplement ELISA tests to reliably check for Scorch and Shock viruses in young plants before using them to grow new crops.
“These findings have a big economic impact on the sector,” said Dr. Gerbrandt. “These viruses are one of the most economically significant challenges we face, and this work has helped bring the importance of viruses to growers’ attention so they can better manage infected fields.”
“This project is a perfect example of how genomics can be a powerful tool for solving real-world challenges facing our industries,” said Suzanne Gill, President and CEO of Genome BC. “By connecting researchers with industry partners, we’re helping to turn a frustrating problem into a workable, data-driven solution that protects a vital part of our province’s economy.”
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Contact: Genie Tay, Communications Specialist, Genome BC
