Earlier this month, Citrus Industry reported in an article that University of Florida (UF) Extension entomologist Lauren Diepenbrock discovered a pest not previously found in Florida citrus. The pest was thought to be an ambrosia beetle.
It has now been determined that two different species of ambrosia beetles (Euplatypus compositus and Xyleborus affinis) have been found. The related fungus is still to be determined and is being cultured by the UF forest pathology lab.
“Based on the species descriptions, both have broad host ranges, so they’ll use a lot of different kinds of trees if the tree is available to them,” explained Diepenbrock. “And when I say available, it needs to be on its way out or dead. So the beetles and their fungus that they bring with them into the trees were not the causal agents for death.”
She said that based on observations at both groves where the beetles have been found, it appears that something else may have pushed the trees over the edge, and the beetles took advantage of the opportunities to colonize. “So signs of these beetles may just be an indicator that a tree has severely declined,” Diepenbrock explained. “That said, we did find fresh holes on neighboring trees that appeared healthy (with HLB but good management). So I’m not sure if that is because the beetles needed to disperse when they emerged, and those trees were just weak enough for them to use, or if those trees are closer to dead than their physical appearance would suggest.”
Diepenbrock said she will be working on some projects in a grove with a heavy ambrosia beetle infestation over the next few weeks to try to learn more.
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