Redbay trees have been decimated around Jacksonville by a fungus spread by a small non-native beetle from Asia.
What to look for: The black Ambrosia Beetle is typically too small to see. It is only 2 mm long. A Laurel Wilt infected tree will have wilted trees that point down to the ground. The top of the crown turns purple. Most of the dead leaves stay on the branches. A cross section will show black fungus rings or scraping the bark reveals dark streaks in the sapwood.
Experimental treatment: Only healthy trees have shown success with a fungicide that is injected into the base of a tree trunk. Holes are drilled into the tree and a macro infusion of a fungicide called Alamo pumped into the tree. The protection will last up to a year and a half. The cost is about $10-$12 per diameter inch.
What not to do: If your tree is infected cut it down and burn the wood. Don't transport the wood or you can move the beetles to new locations. The second best option it to let the wood rot away in its original location. Mulching the wood will not kill all the insects because of Ambrosia's small size.
Here is a great resource for more information and to report any sightings of Laurel Wilt outside of the First Coast Area. fs.fed.us/r8/foresthealth/laurelwilt/