What are Lilac/Ash Borers?
There are several species of lilac/ash borers that are considered wood-boring pests in our landscapes. These particular borers will feed on ash, birch, fir,oak, pine, as well as various stone fruit trees. Larvae are white bodied with a black head and are between 1-1.5 inches long at maturity and will pupate into moths. The adult moth will have long, narrow front wings and shorter, wider, back wings. In the adult stage the moth closely resembles a yellowjacket or paper wasp.
What are signs of the Lilac/Ash Borers?
Stressed ash trees are of major concern when it comes to this particular insect. Many of these stresses include bark damage, over/under watering, improper plant depth, and recent transplanting. Unhealthy trees will have a tougher time naturally fending off this borer. You can identify an attack by inspecting the trunk of the tree for 1/4 inch round exit holes and visible sawdust at the base of the tree. Another way to identify an attack is to find a papery type, clear, pupal remnant the moth will leave behind as it exits the tree.
Certain trees on your property to include parkway planted trees, recently transplanted trees, and trees receiving less than optimal watering will be at higher risk of a Lilac/Ash Borer attack. A preventative spray of insecticide is recommended in order to control the larvae before it enters the trunk of the tree. These insecticides are applied directly to the trunk of the tree and will give season long control against any borer type pest. Soil type applied systemic insecticides are not recommended for this particular insect.