Laurel Wilt and Ambrosia Beetles in Northeast Florida

Laurel wilt is a fungal disease carried by the redbay ambrosia beetle, a tiny non-native insect that arrived in the United States around 2002. The beetle bores into a tree and introduces the fungus, which the beetle farms as a food source. The fungus blocks the tree’s water-conducting tissue, and the tree essentially dies of thirst.

It attacks members of the laurel family: redbay and swamp bay most severely, plus sassafras, avocado, camphor, pondspice, and silkbay. It does not attack oaks, pines, palms, magnolias, or maples.

The speed is what shocks people. A mature redbay can go from healthy to dead in a few weeks.

The symptom pattern is distinctive enough to be nearly diagnostic on its own.

An infected tree cannot be cured. Once the fungus has colonized the vascular system, there is no treatment that restores it, and the tree should be removed before it becomes a hazard — dead redbays lose structural integrity quickly.

Preventive treatment exists for high-value uninfected trees. A systemic fungicide injection can protect an individual specimen for a period of time, and it needs repeating. It is a reasonable investment for a landmark tree or a productive avocado; it is not realistic for a woodlot full of redbay.

The most useful thing you can do is manage the wood. Infected wood harbors the beetle, and moving it is a primary way the disease spreads to new areas. Do not transport it, do not sell or give away firewood from an infected tree, and where possible chip or dispose of it on site. This is exactly the kind of situation where a professional tree removal service that understands the disease matters more than the cheapest bid.

The redbay ambrosia beetle is a special case because of the fungus it carries. Most other ambrosia beetle species are secondary pests: they attack trees that are already stressed and dying rather than healthy ones.

The telltale sign is the toothpick — fine strands of compacted frass protruding from small round holes in the bark, sometimes several inches long. Granulate ambrosia beetles hit stressed ornamentals and young trees, particularly after flooding.

When we find that on a tree, the diagnosis is not really "beetles." The diagnosis is whatever weakened the tree first: flooded root zone, drought stress, construction root damage, or transplant shock. Spraying does not fix any of those. Correcting the underlying stress does, and that is where our tree disease and pest treatment work starts.

While we are on beetles: the ones that concern pine owners in Elkton and rural St. Johns County are Ips engraver beetles and southern pine beetle, not ambrosia beetles.

The signs are pitch tubes — popcorn-sized blobs of resin on the trunk — reddish boring dust in bark crevices, and needles fading from green to yellow to red across the whole crown.

Like ambrosia beetles, Ips typically attack stressed pines: drought, lightning strike, root damage, or recent construction. Prompt removal of an infested tree protects the pines around it, because populations build in dying trees and then spread.

Do not move the wood. That is the single most important thing.

Get the tree identified properly — plenty of trees brown out for other reasons, and the treatment path is entirely different if it turns out to be root drowning or drought stress.

For confirmed laurel wilt, plan removal before the tree deteriorates structurally, and consider what to replant. Do not put another redbay in the same spot. Live oak, southern magnolia, and other non-laurel species are unaffected — our guide to the best trees to plant in Northeast Florida covers good replacements.