But establishing how the fungus - Diaporthe in its sexual state and Phomopsis in its asexual state - behaves and developing treatment is proving challenging.
"We consistently found the fungus in cases of blackcurrrant dieback, but the epidemiology isn't understood," he said. "Disease management strategies need to be developed here."
Similarly, blueberry dieback causes "antler-like" damage on bushes, he said. "Phomopsis is the most widely found pathogen, but that doesn't prove its pathogenicity. We aren't convinced there is a single cause."