
Trees are an important part of the Florida landscape. They provide shade, beauty, and a home for wildlife. But like all living things, trees are susceptible to diseases. Some tree diseases are caused by fungi, bacteria, or viruses, while others are the result of environmental stressors such as drought or poor nutrition.
While some tree diseases can be treated, others can be deadly. That’s why it’s important to know how to spot the signs of a sick tree. In this blog post, we’ll discuss some of the most common tree diseases in Florida and how to identify them.
Fusarium Wilt
Fusarium wilt is a soil-borne fungus that affects more than 100 species of trees and shrubs worldwide, including oak, maple, elm, and cypress trees. In Florida, fusarium wilt is most commonly found in oak trees. The disease gets its name from the fungus Fusarium oxysporum, which clogs the tree’s vascular system and prevents water and nutrients from flowing freely to the leaves.

Symptoms of fusarium wilt include wilting leaves (usually on one side of the tree), yellowing leaves, and branch dieback. The disease is often first noticed during hot, dry weather when other trees are healthy and thriving. Once a tree is infected with fusarium wilt, there is no cure. The best course of action is to remove the affected tree before the disease has a chance to spread to other trees.

Oak Wilt
Oak wilt is another fungal disease that affects oak trees. Unlike fusarium wilt, which attacks the vascular system of the tree, oak wilt infects the sapwood—the outer layer of wood just beneath the bark—of affected trees. The fungus blocks the flow of water and nutrients within the sapwood, causing leaves to turn brown and wilt from the tips inward. Oak wilt can kill a tree in as little as six weeks!
The best way to prevent oak wilt is by pruning your oak trees during the dormant season (winter). This will help reduce the risk of wounds that could provide entry points for the fungus. If you think your oak tree may be infected with oak wilt, contact a certified arborist immediately for a diagnosis and treatment plan.
Cypress Canker Disease
Cypress canker disease is caused by one of two fungi— Seiridium or Phytophthora—that attack cypress trees through wounds in their bark or branches. Cypress canker disease weakens trees by causing them to lose their ability to transport water and nutrients up from their roots. This leads to dieback of foliage at the tips of branches, yellowing or browning leaves, and ultimately death if left untreated.

Cypress canker disease is difficult to control once a tree is infected because there are no known treatments that are effective against either Seiridium or Phytophthora fungi. The best way to prevent cypress canker disease is by maintaining healthy trees through proper watering, fertilization, and pruning practices.

Powdery Mildew
Powdery mildew is a fungal disease that affects many types of plants, including trees. It is characterized by a white or gray powdery growth on the leaves, stems, or branches of the affected plant. Powdery mildew usually appears first on new growth or in shady areas of the plant where there is little airflow. If left untreated, powdery mildew can cause leaves to yellow or brown and eventually drop off. To prevent powdery mildew, make sure your trees are getting enough sunlight and air circulation. If you see signs of powdery mildew on your trees, contact a certified arborist for treatment options.
Trees are an important part of Florida’s ecosystem but they are susceptible to diseases that can kill them quickly if left untreated. Some common tree diseases in Florida include fusarium wilt, oak wilt, and cypress canker disease. Symptoms of these diseases include wilting leaves, yellowing leaves, branch dieback, and leaf death starting at the tips of branches and working inward. There is no cure for most tree diseases but you can prevent them by maintaining healthy trees through proper watering, fertilization, and pruning practices. If you think your tree may be sick, contact Tree Care By Robert Miller for a free consultation today!