Opinion: Stepping Up To Squash A Threat

A working group tackling the slow march south of the red bay ambrosia beetle and the pathogen it carries is still hard at work. The disease is threatening Florida’s $13 million-a-year avocado crop.

A beetle was found March 3 in an avocado tree in a West Kendall neighborhood. It was the farthest south a beetle has been found as it has progressed southward during the past few years into Florida from other Southeast states. Only seven miles lie between that tree and the 7,000-plus-acre avocado-producing region to the south in Miami-Dade County.

A protective zone was set up at a rapid clip. Almost 100 traps for the beetle have been laid around “ground zero,” with 20 installed within a 1-mile radius of the site. A team from the Cooperative Agricultural Pest Survey Program (CAPS) is checking the traps every two weeks, and the good news is, as of presstime, no more beetles have been found.

Survey teams also are checking trees for symptoms of laurel wilt disease, which the beetle carries. To date, no trees in that particular area have exhibited the typical symptoms that characterize an infected tree, which can include leaf and young stem wilting, leaf color changes from light green to greenish-brown, dead leaves, and stem and limb dieback. (A side note, however: Those symptoms also might indicate a tree has been struck by lightning.)

Preparing For Battle

Richard Gaskalla, who leads the Florida Department of Agriculture’s Division of Plant Industry (DPI), points out the need for a long-term surveillance program to eventually take the place of the work of CAPS, which he likens to the Marines: When a disease or pest is found, “they move in and establish a beachhead.” Funding — perhaps from the 2007 Farm Bill — must be found for the program to continue the battle on an ongoing basis.

The state also is preparing to ask the EPA for a Section 18 emergency exemption to allow the use of the Syngenta product Tilt (propiconazole), which may control laurel wilt when used as a preventive measure. Researchers are still working to determine the best application method and the optimum rate for young and mature trees.

Emergency exemptions come into play when a pest or disease threatens a crop and there are no other alternatives for controlling it. Typically, a request involves a pesticide already in use for other purposes, so it’s a chemical with which EPA is familiar.

Advocacy For Avocados

On other fronts, a subcommittee charged with getting the word out about what’s being done to combat disease has been busy with its “Save the Guac” campaign. A recent strategy was to use the Cinco de Mayo holiday as an opportunity to talk about the disease and how consumers can help stop it from spreading. The outreach effort also has targeted residents, campers, landscapers, municipal waste entities, and community organizations. And the subcommittee is working to ensure that industry is aware of the working group’s activities.

Jonathan Crane, UF/IFAS tropical fruit specialist, is working with more than a dozen Extension directors to set up meetings with county government representatives, such as arborists and waste management officials, to make them aware of the disease and precautions to be taken when cutting and disposing of trees. Counties where laurel wilt disease has been found and those on the leading edge of the West Kendall beetle find have been targeted first. In addition, a speakers’ bureau has been set up to inform community and civic groups.

A Collaborative Effort

Also hard at work are researchers from UF/IFAS-Tropical Research and Education Center, the UF School of Forest Resources and Conservation, USDA-ARS in Miami, and the state DPI. Research includes testing of 11 chemicals under varying degrees of pest pressure, studying the behavior of the beetle in trees, researching repellents and attractants, looking at natural resistance to the disease in red bay trees, and studying how the host tree interacts with the pathogen.

In addition, a subcommittee is completing work on a new rule banning movement of locally produced firewood into Miami-Dade County unless it’s been treated and certified by the state as safe.

August will mark a year since the working group moved into high gear as the disease made its presence felt in Florida. It’s a strong example of how industry can come together with researchers, the state, and regulators in a united front to combat a threat. With the alarming regularity that new pests and diseases are found in our state, it’s a model approach to working together for a common benefit.