First
Cases of Laurel Wilt Disease Confirmed in Alabama
Officials with the Alabama
Forestry Commission are concerned but not surprised by the news that laurel
wilt disease has now been found in two counties in Alabama. The U.S. Department
of Agriculture (USDA) and Iowa State University laboratories confirmed that tree
stem samples collected in Marengo and Mobile counties were positive for the
fungus, Raffaelea lauricola.
This non-native invasive insect-disease
complex primarily affects trees in the laurel family, with redbay, swampbay,
camphor, and sassafras being especially susceptible. Other potential hosts in
the laurel species include pondberry, pondspice, spicebush, and avocado. A host
tree becomes infected with the disease when a redbay ambrosia beetle transmits
the fungus into the walls of the sapwood. Quite virulent, the fungus then clogs
the vascular system of the tree, preventing the flow of water. As a result,
black streaks appear in the sapwood. Soon, the entire crown presents wilted
reddish-brown foliage and within weeks, the tree will succumb to the disease.
Laurel wilt disease was introduced into
the United States in 2002 on untreated wood packing material from Asia, first
attacking redbay and sassafras trees in Georgia, then spreading into South
Carolina, Florida, Mississippi, and most recently North Carolina. When two
redbay ambrosia beetles were captured in traps near Grand
Bay, Alabama back in October of
2010, the disease was predicted to spread into Mobile County
within the next few years.
One probable cause for spread of the
disease is the long-distance movement of untreated wood products. Infested
firewood, wood chips, and even yard debris can become possible carriers of the
redbay ambrosia beetle. Avoiding the movement of infested wood and proper
disposal can dramatically reduce the threat.
Unfortunately, very little success has
been achieved in containing redbay ambrosia beetle and the associated laurel
wilt disease through current control methods. There are, however, some actions
that can be implemented to reduce and possibly prevent the further spread of
this devastating exotic pest. Any host tree confirmed of having laurel wilt
disease should immediately be salvaged. If possible, burn the wood debris of the
affected tree on the site, of course, following all state and local regulations.
If burning is not an option, at least leave the cut tree at that location. Do
not haul cut wood debris killed by laurel wilt disease to other sites. Always buy
“local” firewood if travelling to another destination for recreational
activities.
For additional information on the redbay
ambrosia beetle and laurel wilt disease, please visit:
Press Release from: The Alabama Forestry Commission is a
state agency committed to protecting Alabama
citizens and the state’s invaluable forest assets.
