Stressed tree are most susceptible to borer attacks. The insect bores in the sapwood, beginning in the top third of the tree, causing death of the tree crown. The tunnels are slightly raised and faintly rust colored. Emergence holes in the trunk are shaped like capital D's. Keep the trees healthy by controlling other insects, fertilizing, and watering as needed.
Chemical control is applied to the trunk and main branches.
The first spray is usually applied June first with 2 additional sprays at 3 week intervals. Timing of the first spray will vary from year to year depending on weather conditions. A commercial sprayer may be needed to apply the spray adequately. Visuals associated with this text. This information is for educational purposes only.