Inside the Source: Sugarberry Decline
November 21, 2019
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Sugarberry Decline: A Forestry Detective Story
By Andrea Watts
Andy Boone, CF, started receiving the calls toward the end of the summer of 2009. Arborists were perplexed by what they were observing. Throughout the Columbia, South Carolina, area, the vibrant green lance-shaped leaves on sugarberry trees were unexpectedly turning yellow. When the leaves dropped, death followed.
As the former section chief and insect and disease specialist for the South Carolina Forestry Commission, Boone had decades of experience identifying diseases and monitoring insect outbreaks. Following his retirement in 2006, he leveraged this expertise into a business, DendroDiagnostics, and arborists came to him for answers.
The dying sugarberry trees were growing on adverse or unnatural sites was Boone’s initial thought. As a bottomland hardwood species usually found along rivers, sugarberry (Celtis laevigata) wasn’t adapted to the property lines or right-of-ways where it was growing in Columbia’s neighborhoods. Another reason Boone attributed to the die-off was damaged roots, a common occurrence in an urban environment. English ivy and kudzu were also likely a contributing factor, as were insects.
“Then I noticed that not only were the old sugarberries dying off, but groups of younger sugarberries were doing so as well,” he explained. “And that’s when things really jelled in my mind—something that’s not normal is going on.”
Reports of die-offs continued into 2010 and 2011. When the rate of mortality showed no sign of slowing, Boone realized its cause needed to be identified, especially since other species growing at the same sites weren’t exhibiting similar symptoms or mortality.
“It just bothered me as a forest pathologist that there’s something going on around here, and we don’t know what it is,” he said.