Little beetle, big problem.

November 19, 2010

Almost every month, a new exotic insect, plant or plant pathogen is detected in Florida. Some of these exotic invaders turn out to be serious agricultural pests, like laurel wilt disease and the redbay ambrosia beetle.

Pests and diseases like laurel wilt and the redbay ambrosia beetle are often spread throughout the state unknowingly by travelers. For example, the redbay ambrosia beetle can be harbored in firewood, and transporting firewood increases the spread of the beetle and laurel wilt disease.

Laurel wilt is a destructive disease of redbay, avocado and other trees in the laurel family (Lauraceae). The disease is caused by a fungus (Raffaelea lauricola) that infects the sapwood of host trees, restricting the flow of water, causing the leaves to wilt and the trees to die. The fungus is carried into trees by the non-native redbay ambrosia beetle (Xyleborus glabratus), which was first detected in the U.S. near Savannah, Georgia, in 2002 and subsequently found in Duval County, Florida, in 2005. Laurel wilt has caused high levels of mortality in redbay trees in South Carolina, Georgia and Florida, and has affected several other hosts including sassafras and avocado.

Florida’s avocado industry represents a farm gate production value of $13 million with over 6,773 production acres located in Miami-Dade County with some acreage in Collier County, according to Florida Agriculture Statistics. The spread of the tiny redbay ambrosia beetle could result in the elimination of avocado production in Florida.

The Division of Plant Industry’s Save the Guac campaign was established to educate the public about the potential devastating effects laurel wilt and the redbay ambrosia beetle could have on Florida avocado production. According to the report, Estimates of the Replacement Costs of Commercial and Backyard Avocado Trees in South Florida authored by Edward A. Evans and Jonathan H. Crane, the cost to replace commercial and backyard avocados, if the redbay-laurel wilt disease complex became established, would be $423 million. DPI established a firewood and unprocessed wood product regulation in August to protect our trees, natural environments, forest and wood material industries and, of course, avocados.

You can help stop the spread of exotic invasive species like the redbay ambrosia beetle and help Save the Guac by not transporting firewood or unprocessed wood products.

Have questions? Call DPI’s toll-free helpline at 888-397-1517 or e-mail us at dpi-blog@doacs.state.fl.us.

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