Solution Found For Disease Threatening Avocado Production

The redbay ambrosia beetle, Xyleborus glabratus, killed by a fungus founded by a team of UF researchers in order to stop the spread of laurel wilt, a disease that kills several tree species.
The redbay ambrosia beetle, Xyleborus glabratus, killed by a fungus founded by a team of UF researchers in order to stop the spread of laurel wilt, a disease that kills several tree species. Photo by Tropical Research and Education Center

Researchers have found what could be the first biological control strategy against a beetle that is threatening Florida’s avocado industry.

Laurel wilt, a disease transmitted by the invasive redbay ambrosia beetle, threatens the state’s $54 million-a-year avocado industry, according to a University of Florida press release.

UF scientists collaborated with other researchers from the Tropical Research and Education Center (TREC), USDA and the Indian River Research and Education Center in Fort Pierce to propose an alternative method of using a fungi rather than insecticides to manage the threat.

“(The strategy) is giving the growers more tools to manage the problem,” said Daniel Carrillo, an entomology research assistant professor at the TREC in Homestead. “(Insecticides) are just one tool more to try to control the problem.”

The biological control strategy could help growers use less insecticide. Insecticides are chemicals that can be toxic to both animals and humans.

“When you are dealing with a pest, you try to have an integrated approach,” said Carrillo. “We have multiple tactics, not just one. You have to try to use them all.”

Laurel wilt is responsible for spreading and killing many bay trees that are, or were, abundant in Florida. Specifically, trees of the Lauraceae family, which includes avocados. The fungus affects the beetles, not the laurel wilt disease itself.

“What we’re trying to do is develop a biological tactic that is environmentally sound,” he said. “We’re trying to control the beetles that are spreading the disease.”

Florida produced 30,700 tons of avocados just in 2013 that totaled to $24,437,000, according to the U.S. Department of Agriculture’s National Agricultural Statistics Service.

“What we are proposing is to use a biological control strategy (fungi) that attacks the insects,” said Carrillo. “They’re less harmful to other organisms and do not infect humans, so they’re more environmentally friendly.”

Carrillo said the controlled fungus may be applied to the trees with the idea that the beetles come in contact with it, get infected and are ultimately killed without harming the environment.

Jonathan Crane, a tropical fruit crop specialist for the Department of Horticultural Sciences, is familiar with the project and worked with the collaborators on the strategy. Crane said this is one of many strategies being investigated.

“There’s a two-pronged approach,” he said. “There’s controlling the disease — the fungus — and there’s controlling the beetles that spread the fungus.”

Agriculture Commissioner Adam Putnam addressed the concern of laurel wilt in a commercial avocado grove after it was found in Miami-Dade County in 2012, according to a press release.

“Unaddressed, the disease can spread quickly, threatening the health of South Florida’s commercial avocado industry,” Putnam said.

Carrillo said neighboring and surrounding trees or groves to any initial infected tree would also get infected if the disease was not controlled and managed in a timely manner.

Researchers have not only recently identified a control strategy for this non-native beetle, but they’ve also discovered that native types of ambrosia beetles are also capable of carrying the pathogen and transmitting the disease.

“The issue is more complex. We’re not dealing with just one species; we’re dealing with multiple species,” said Carrillo. “Now what were trying to do is figure out how to apply (the strategy) in a commercial setting.”

Until the strategy is commercially implemented, researchers have put together a set of recommendations for growers to help prevent the spread of laurel wilt and the redbay ambrosia beetle on the Florida Department of Agriculture and Consumer Services website.

Editor’s note: This update corrects an earlier version of the story.

About Christy Wideman

Christy is a reporter for WUFT News and can be contacted by calling 352-392-6397 or emailing

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