Mar 20 2009

Redbay Ambrosia Beatle Injecting Deadly Fungus in Central Florida Trees

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Tree Disease found in Daytona Beach

This week (Jan 27, 2009) a lethal tree disease, Laurel wilt disease, was positively identified in Daytona Beach.  The disease was confirmed from a sample collected and cultured by the Florida Dept. of Agriculture and Consumers Services. It first appeared in 2002 when a small beetle was found near Savannah, Ga.  It was identified as Asian in origin and one that vectors a fungus that is lethal to the laurel family of plants (laurel oak – Quercus laurifolia, is not a member of this plant family).  This insect-vectored fungal disease is a concern because by the end of 2006, 92% of all red bay trees (Persea borbonia) in a Jacksonville study area died over a two year period.  This group of bay trees (Persea borbonia –common in hammocks, Persea palustris-common in wetlands, Persea humilis- common in scrub and sandhill) comprise between 2 and 16% of the forest systems in Volusia County.

Laurel wilt disease is caused by a non-native fungal pathogen vectored by a very small introduced ambrosia beetle, approximately 2 millimeters in size (3/16 of an inch).  In addition to the common Persea species, the fungus, carried by the beetle, can kill other members of the laurel family including sassafras (Sassafras albidum), and a few uncommon native shrubs.  In addition, cultivars of the agricultural and ornamental avocado (Persea americana) are also susceptible.  Currently, laurel wilt occurs in Duval, St. Johns, Putnam, Marion, Alachua, Union, Bradford, Baker, Nassau, Clay, Brevard, Indian River, and Flagler Counties, as well as southeastern South Carolina, and eastern Georgia, and now Volusia County.

Although the bay group is not widely used commercially, the disease has aesthetic and economic impacts since bay and avocado trees occur in residential landscapes.  Laurel wilt disease can cause trees to die within a few weeks, which can become hazards to people, homes, and businesses.  This alone should be of concern to each municipality and County government.  An additional concern is the future of the Palamedes Swallowtail butterfly.  This is an insect whose only source of food and host for reproduction are the red bay trees.

There are currently several researchers investigating the potential for pre and post tree inoculations.  To date the results have produced mixed results.   Fungicide treatments are currently being tested but it is too early for the Florida Department of Agriculture and the Division of Forestry to make any specific recommendations.

Laurel wilt disease is similar to Dutch Elm Disease, a disease that devastated the population of elm trees in the Midwest, northeast, England, and Canada.

The Laurel Wilt Working Group has offered the following management considerations to reduce unnecessary spread of the disease:

    • Whenever possible, leave dead and dying red bay or other host material on site instead of transporting it.
    • If the wood must be transported, dispose of it as locally as possible. Avoid transporting red bay wood outside of the county in which it was cut.
    • Use of landfills, covering, burning, or chipping host tree material at its original site or a disposal site is preferable to leaving it intact in the open environment.  Chipping wood from an infested tree might not destroy all of the ambrosia beetles (due to their extremely small size), but should reduce the suitability of the wood as breeding material and hinder beetle colonization and dispersal.
    • Although the disease pathogen has not been documented to spread by any means other than the beetle vector, consider cleaning/sterilizing saws and pruning blades after cutting an infected tree and before using them on uninfected host tree species.

More information about laurel wilt is available at:, and

Don Spence, M.S.

Certified Arborist/Municipal Specialist, Fl-1341AM

Plant Ecologist

Stetson University, Adjunct Professor of Biology

Daytona State College, Adjunct Professor of Biology and Botany

Native Florida Landscapes, LLC
Environmental, Vegetation, & Landscape Consulting
108 Ocean Aire Terrace South
Ormond Beach, Fl 32176

View Insect Infesting Central Florida Redbay Trees

View Insect Infesting Central Florida Redbay Trees

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