What causes stress?
Some of the many stress factors that can affect your trees are: air pollution, drought, mechanical injury, adverse soil conditions and winter injury. Two other major causes of stress are insects and diseases, which destroy or impair the function of leaves. Leaves are the important energy manufacturing system in trees.
A variety of insect pests feed on trees, including leafminers, scales, mites, weevils, leaf-chewing caterpillars and beetles. Research shows that trees affected two years in a row may be killed or thrown into an irreversible decline. Some leaf diseases can weaken trees and subject them to attack by other insects or fungus.
What can be done to alleviate tree and shrub stress?
Spraying or soil injection treatments are effective techniques to reduce insect populations in trees and minimize plant damage. A preventative maintenance inspect and treat program provides the best protection. Winter dormant oil applications suppress many scale insects, mites and eggs that settle on trees in the winter.
These treatments should be followed by three or four "inspect and treat" visits from your local arborist during the spring and summer or as needed. Applications may not be necessary on every visit, but evaluation by a Davey arborist is necessary to determine the best option for avoiding pest damage.
In conjunction with pest management, proper fertilization, mulching and watering can also help to alleviate stress.