Despite the unpleasant appearance, the retention of dead leaves following tree death is a helpful survey tool. Each winter, the N.C. Forest Service canvases areas near the known range of laurel wilt in the state to determine if the disease has spread to new areas. They scan forests for small- to medium-sized trees that are holding onto their reddish-brown leaves. Upon spotting one, the survey team will pull over for closer inspection. Winter is the ideal time for this because the leaves of other trees do not get in the way and surveyors can view much farther into the forest.
Laurel wilt is a fungal disease spread by a small beetle called the redbay ambrosia beetle. As a group, ambrosia beetles bore into trees, inoculate the galleries within the wood with a fungus, and feed upon the fungus. Most species of ambrosia beetles attack weakened or dying trees and typically the fungus does not kill the tree. However, in the case of the redbay ambrosia beetle, it not only attacks seemingly healthy redbay trees, but the fungus is essentially toxic to the tree. A single attack by a beetle can inoculate a tree with the fungus and result in tree death in a few short weeks.
To date, close to half a billion trees in the Southeastern U.S. have been killed by laurel wilt since it was initially detected in 2002 near Savannah, Ga. Laurel wilt was first found in North Carolina in 2011 and is now known to occur in six counties: Bladen, Brunswick, Columbus, New Hanover, Pender and Sampson. While the disease has only affected redbay trees in North Carolina, sassafras, avocado, spicebush, pondberry (a federally endangered species), pondspice (a species of concern in North Carolina), and other plants in the laurel family are also susceptible (mountain-laurel is not affected).
So, enjoy your Florida-grown guacamole while you can… it may have a limited lifespan. In fact, the Florida Department of Agriculture & Consumer Services launched a ‘Save the Guac’ campaign to raise awareness of the disease and the harmful impact that moving firewood may have in spreading this disease. To learn more about laurel wilt, refer to the N.C. Forest Service laurel wilt page.