After Freeze, Ambrosia Beetles Are Potential Threat

Florida citrus growers should be on the lookout for an uncommon citrus pest following the recent freeze events that devastated crops throughout the state.

During a recent postfreeze webinar hosted by the University of Florida Institute of Food and Agricultural Sciences Citrus Team, Lauren Diepenbrock, associate professor and entomologist, warned growers about the ambrosia beetle. This pest can prey on trees postfreeze.

“Ambrosia beetles are highly attracted to stressed trees. They’re not specialists on citrus. They’re just in the habitat and tend to be in our woods,” Diepenbrock said. “What you’ll see as far as the visible damage is these kind of sawdust needles extending from the side of the tree. That is where the pest has burrowed in.

“They lay eggs on the inside. What they do is cultivate a fungus in the vascular tissues of the tree. That vascular tissue can cause further damage to the tree, especially trees that are already sick from HLB (huanglongbing, commonly known as citrus greening).”

Ambrosia beetles mostly attack pecan trees and can be especially problematic in orchards located in Georgia and Alabama. Young trees are most susceptible, as are those that are growing under stressed conditions.

There are insecticides available to successfully manage the pest. Growers just need to know when their trees are being attacked. Farmers can identify beetle activity by the toothpick-sized sawdust tubes that beetles leave sticking out of holes bored into trees.

“This is something to keep an eye out for. There are some chemistries available. It probably won’t be a problem in a lot of areas,” Diepenbrock said. “If you see it, reach out to your Extension agent or specialist, and we can help you with the management.”

Learn more about ambrosia beetle monitoring and management here.