Laurel Wilt

Raffaelea lauricola

Laurel wilt is an invasive deadly vascular wilt disease of red bay and other trees in the Lauraceae family, caused by the fungus Raffaelea lauricola. The fungus is carried by a recently-introduced ambrosia beetle, Xyleborus glabratus. The ambrosia beetle bores into the sapwood of stems and branches, and transmits the fungus into the tree where it moves systemically. With the tree’s water conducting cells plugged up by the fungus, the tree begins to wilt.

Laurel wilt has caused widespread mortality of trees, in parks, forests, and residential landscapes on the coastal plains of South Carolina, Georgia, and Florida.

Download Laurel Wilt Fact Sheet

Treatment Strategy

The treatment of laurel wilt involves protecting high value tree with a fungicide called Alamo®. Targeting the beetle that transmits the disease is of limited value because the fungus will be transmitted regardless of the beetle's survival.

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Laurel Wilt Treatment Option 1

Trial data suggests that preventive treatments with Alamo®, injected by a process called macro-infusion, will protect trees for at least 12 months. This suggests re-treatments be needed every 12-14 months. Infected trees, if treated promptly, can recover; however, if more than 25% of the crown of the tree is wilted, there will be little chance of success.

Laurel Wilt DIY Kit

Application TypeLow Volume Macro Infusion

DIY Product/Equipment Needed:

• Alamo®

• Low Volume Macro Infusion Kit

• Stiff bristled hand brush

• Drill

• Shovel

• Gloves

How Is It Spread?

The red bay ambrosia beetle has an intimate relationship with the laurel wilt fungus. It is their primary source of food, and they use susceptible trees to “farm” the fungus. Red bay ambrosia beetles carry the laurel wilt fungus in their mouth. After infecting a healthy tree, the ambrosia beetle returns to lay its eggs once the tree begins to die. When the beetle larvae hatch, they feed on the fungus for approximately 40-50 days. Once they become adults, they leave the tree and the cycle of death repeats itself.

Susceptible Trees

Redbay, sassafras, pondberry , pondspice, avocado and camphor tree

Symptoms

• Drooping, wilted leaves with reddish to purplish discoloration occurs on branches and progress throughout the entire canopy.

• Leaves eventually turn brown and may stay on the tree for up to a year or more.

• A dark, blackish discoloration can be seen in the sapwood when removing the bark from wilted trees or by cutting cross sections of the stem.

• Wilt symptoms on camphor tree may not progress through the entire crown.

• String-like tubes or piles of fine sawdust may be seen on the bark of trees that have wilted. These are produced by potentially multiple species of ambrosia beetles (including the redbay ambrosia beetle) or other secondary wood borers.

Lookalikes

None

Related/Similar Problems

Ambrosia beetle

Timing

Year round

Urgency

High

Risk of Spreading

High

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