UF/IFAS Extension offices and master gardeners frequently receive questions from homeowners about the health and viability of their lawn and landscape plants. By far, the most valuable, long-term investments in the landscape are trees. They provide structure, shade and shelter. Mature trees add resale value to a property too. It is worth taking time to maintain them with proper care.
We irrigate, fertilize and hire professionals to prune and trim when necessary. But some families of trees are susceptible to specific pests. Two of them and their pest insects are found in Florida.
The Redbay tree is a favorite of the Redbay Ambrosia Beetle, Xyleborus glabratus. The insect is only two millimeters in length. What can it do to a young or even a mature tree? Unfortunately, the female beetles bore into the bark of the tree, carrying the spores of a fungus in their mouths. These spores are deposited into small tunnels (galleries) in the sapwood. Then the spores mature into the fungus that causes Laurel Wilt Disease. The fungus grows and prevents the movement of water and nutrients within the tree. The tree dies.
Ash trees up north are facing a similar problem from a different pest insect, the Emerald Ash Borer (EAB), Agrillus planipenis. It this case, the insect does not carry a fungus. The adult EAB is much larger than the Redbay Ambrosia Beetle. It can reach 1 ½ centimeters (about 5/8”) in size. But while the adults may eat ash leaves, its larva do the real damage. The adult female bores into the bark to the nutrient-rich layer underneath. It deposits eggs which develop into larva. The larva feed on the sugar and water conducting cells just below the bark. Without its nutrients, this tree dies also. This insect is not in Florida yet, but the Florida Forest Service is monitoring for it.
Both boring insects kill their target species. Unfortunately, the dead trees provide a resource that is particularly popular to people - scrap wood. The fungus and spores of Laurel Wilt Disease as well as the eggs/larva of the EAB are still viable in dead wood. One of the easiest ways for them to be transported great distances to new areas is when untreated wood is used for pallets or firewood. You may not be constructing pallets, but collecting and carrying firewood is common. If you buy firewood, make sure it is from a local source. Campers and hikers should burn wood where they find it. Do not bring it home.
For more information about the care of landscape trees or shrubs call or stop by the Hernando County UF/IFAS office (352-754-4433) 16110 Aviation Loop Drive, Brooksville, 34604, weekdays from 8 to 5; or the Master Gardener nursery at 19490 Oliver Street (behind the Hernando County fairgrounds). The nursery is open from 9 to noon Wednesdays and the first Saturday of each month.