How To Protect Your Trees From Insects and Disease

How To Protect Your Trees From Insects and Disease

Trees are an essential part of landscaping for many of us and a costly one at that. After putting time, effort and funds into beautifying our landscape with trees, it would be devastating to see them destroyed by disease and insects. So, how do we protect our leafy friends? The key to protecting our trees is of course, prevention.

Be sure to plant trees that are a good idea for your location and resistant to the common disease and insect infestations for that area. Also, know that most disease and insects will take advantage of trees under stress. Just as disease can attack a person with a weak immune system, so it is with the trees. So, just as you need to eat healthy and take in plenty of water, make sure your trees are being properly watered, mulched and pruned to prevent outbreaks.How To Protect Your Trees From Insects and Disease


Powdery Mildew is a disease that makes your plants look as though they’ve been sprinkled with powder. Powdery Mildew is often found on Crabapple trees, Dogwoods, English Oak and catalpa trees. Generally, older leaves are attacked first. If a new shoot is attacked, you’ll notice leaf curling and shoot twisting. Powdery mildew can make your plants/trees look less beautiful but it won’t usually kill your trees. To prevent it, make sure there’s never standing water on the leaves for long periods of time. Water early in the day and make sure your tree is getting plenty of sunlight and air circulation.

Leaf Spots such as tar spot and frogeye, can cause homeowners worry but usually do minimal damage. Rarely are fungicides necessary. These diseases like to winter on fallen leaves and then re-infect trees in the Spring. The best protection for fungal leaf spots is to rake up leaves and remove them from the area.


Chewing insects eat your tree’s leaves. Examples are cankerworm, tent caterpillar, gypsy moth, leaf miners and Japanese beetles. Trees usually bounce back from these kinds of intruders but if they’re continually being attacked, these bugs can eventually kill your them.

Boring insects tunnel into the stem, roots or twigs of a tree. Sometimes offspring from the eggs of these insects burrow even deeper into the tree cutting off the tree’s water conducting tissues.  In the case of serious infestations, the upper leaves can be starved to death and your tree can die. Keep an eye out for entry and exit holes in the bark, mounds of saw dust around the base of the tree and branch wilting and dying.

Sucking insects such as scales, do their dirty work by sucking the liquid from leaves and twigs. If you see scaly formations on branches, leaf dieback and sticky sweet secretions, suspect these guys. Aphids are also of this group of insects.

The best thing to do is to keep a watchful eye on your trees and plants especially during growing season. Note any changes as early detection can be treated best.