A Brief Guide on How to Stop Tree Pests

Insects eat plants. That’s part of the natural order of things, and it’s to be expected that insects and other pests will feed on your trees. It sounds nasty, but reducing this to zero occurrence is virtually impossible.
But sometimes tree pests cross the line, and that line is when they become a problem for tree care. Sometimes tree pests even grow too numerous, to the point of doing actual damage to your trees.
So here are some ways to beat those pesty tree pests in order to protect your trees.
What are some common tree pests?
Each tree species has its own particular bugs that like it best, but some of the more common tree pests include:
- Whiteflies
- Aphids
- Thrips
- Scales
Which types of trees are commonly affected?
Hardwood trees are sometimes plagued by:
- Gypsy moth larvae
- Emerald ash borers
- Longhorn beetles
- Tent caterpillars
Conifers may fall prey to:
- Bark beetles
- Weevils
- Spruce budworms
- Tussock moth larvae
- Wooly adelgids
You can find more detailed information about the various vermin that attack trees in North America here.
What are the problem signs?
General signs of infestation include:
- Discolored, yellow leaves
- Drooping needles
- Insect droppings clustered on the leaves
- Webbing and clusters of cocoons in the case of tent caterpillars
- Other larval insects
Some of these may be signs of plant diseases or nutritional deficiencies, or even lack of water, so it’s best to study the specific pests that attack your trees and look for multiple signs.
The Best Prevention Methods
The best way to handle pests is prevention. Planting diverse species helps prevent serious infestations, since bugs like to look for a feast of the food they love best. Make sure your trees are properly fertilized and watered, use safe pruning methods, and watch for signs of any trouble. Healthy trees are better at resisting insects than stressed and unhealthy trees.
Some plants have natural insect-repellant properties and can help keep everything in your yard and garden safer from the six-legged menace. These include marigolds, chrysanthemums, nasturtiums, and others. Planting these in strategic locations in your yard can help keep bugs away from your trees and other plants.
It’s All About Control.
A tactic that often works when you find an insect problem is to introduce the pests’ natural predators, which are usually other insects but sometimes extend to lizards, frogs, or some birds. Ladybugs are voracious aphid eaters. Certain parasitic wasps go after larval pests. Each insect has one or more critters that find it delicious, and usually an animal that eats bugs won’t also be interested in eating your trees.
Insecticides should be treated as a last resort, but for serious infestations careful and controlled applications of pyrethrins or other chemicals may be called for. When using insecticides, stay with narrow-spectrum bug killers and avoid neonicotinoids, which have been shown to destroy bee colonies.
Generally speaking, a few insects in your trees aren’t a serious problem, but when they show up in great numbers and begin to damage your trees’ health, that’s when you need to take action.
For serious infestations or for more information and general advice, consult a local arborist or tree care professional.