Insect Control Treatments for Borers in Trees
Borers are the most devastating insects that attack trees and shrubs. The Emerald Ash Borer (EAB), has its own page on our website, but EAB is not the only Borer killing valuable trees and shrubs in Northern Illinois.
Varieties of borers include:
The ‘Common’ Lilac Borer was attacking Ash trees long before EAB showed up.
The Bronze Birch Borer attacks the beautiful and valuable White Birch.
The Zimmerman Pine Moth Borer has also been a long term problem, killing Scotch and Austrian Pines.
The Locust Borer attacks Locust and the Lilac Borer attacks Lilacs.
Although there are other Borers, these are among the most common.
Borers come from adult beetles that lay eggs in the cracks and crevices of bark. The larvae that hatch burrow into the bark and live just beneath it.
Their feeding and tunneling stops the flow of water and nutrients through the tree by cutting off the flow of conducting vessels. Leaves on branches above the damaged areas start yellowing and thinning. The top of the tree usually shows the earliest damage, and progresses downward from there.
An experienced Arborist can usually spot the telltale external evidence, which is different on all varieties of trees these insects invade.
Treatment for Borers
Once Borers infest a tree, the results are always fatal if left untreated. Tree Green has found that the best way to combat Borer issues (other than EAB) is as follows:
- Systemic insecticides are injected into the sap system of the tree. The insecticide then travels throughout the sapwood that the Borers are feeding on, killing the insects. We have also found that changing the taste of the sap through the injection process dissuades the sapsucking woodpeckers from visiting the tree.
- We recommend spraying the tree during the periods when newly arriving adult beetles are mating and depositing their eggs.
- We always recommendﾠroot fertilizationﾠfor urban trees, and especially for stressed trees. The healthier a tree, the less likely that it will succumb to Borers or other environmental stressors.