Flourishing Flora: 4 Tree Diseases and How to Prevent Them

Written by  //  February 17, 2017  //  Landscaping  //  Comments Off on Flourishing Flora: 4 Tree Diseases and How to Prevent Them

Though trees are strong and many of them are very long-lived, they are still subject to diseases. You might may go out to your yard and see that some branches of a tree are leafless, or the leaves are spotted or withered. Following are four diseases that attack trees, and what you can do about them. For more information, contact a tree service in your area.

Leaf Spot Disease

This disease is caused by different bacteria and fungi and is spread via wind and splashing water. Water, whether it be from rain or a splashing garden hose, forms a film that allows the pathogens to migrate to new leaves and into the soil.
Leaf spot presents as small yellow spots that turn brown. Often, the spots join to produce large, ugly blotches. The leaf turns yellow, withers and drops. If the disease isn’t halted, the tree can become defoliated and weakened. The disease usually begins on the lower part of the tree and creeps upward.

Treat leaf spot by removing the infected leaves from the tree and raking up infected leaves that have fallen. They should be destroyed and not be placed in the compost pile.

The disease can be combated by not planting trees too close together, and to prune and trim trees so that they get a good amount of light and air. Watering and mulching the trees so that the soil stays moist will reduce the stress that weakens the tree’s immune system.


Rust is another problem caused by a fungus. It appears in summer and early fall when the nights are humid and cool. When a tree has rust, its upper leaf surfaces have white or yellow spots while the undersides have orange or yellow pustules. The leaves wilt and hang down along the stem. The pustules proliferate and can destroy the leaf.
Remove and destroy the infected leaves, and try to plant trees that are resistant to rust. Water the tree in the morning, and avoid getting water on the leaves.

Slime Flux

This disease, also known as bacterial wetwood, is a disease of hardwood trees such as oak and maple. It is caused by bacteria that attack the heartwood and sapwood after the tree has suffered an injury. It presents as a wet, weeping area on the bark as the tree tries to isolate the infection. Arborists say that an otherwise healthy tree can heal itself of slime flux. The disease can be prevented by making sure the tree is not injured when it is transplanted or pruned.

Fire Blight

This disease attacks fruit trees and is caused by a bacteria. It makes leaves, twigs and flowers look scorched. Eventually, it affects most of the tree and makes it look like it’s been in a forest fire. The infected parts of the tree should be removed and destroyed, and the tree should be cut back to healthy branches. Fire blight is controlled through judicious pruning and bactericides.

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