It is so early in the season in many regions buds have not yet broke, but insects have awoken. Being the first to become active has some advantages for the insects, but for landscape professionals and homeowners they can be quite a nuisance. Being that the season for insect control hasn’t begun in earnest up north, it is difficult to time applications for control appropriately or use an effective product. But with help from citizen scientists and homeowners, arborists may be able to positively identify pests in time and schedule appropriate treatments. Three insect pests already on the scene causing trouble are the boxelder bug (Boisea trivittata), the euonymous leafnotcher caterpiller (Pryeria sinica) and the eastern tent caterpillar (Malacosoma americanum).
Boxelder bugs have already been noticed flying around maple trees in Maryland earlier this month. They feed on developing seeds of boxelder (Acer negundo) and other maple species (Acer spp.). Adults do not normally cause visible damage to trees warranting intervention. However, take note of where they are seen flying now and monitor this area closely (or notify your arborist) during the late summer and early fall; bugs will aggregate on these sites and then search for shelter in your homes as the weather cools.
The euonymous leafnotcher caterpillar becomes active very early in the season. Look for eggs along the stems of Euonymus japonicus and Euonymus kiautschovicus. This caterpillar has also been identified already in mid-Atlantic states and will be active elsewhere as temperatures continue to rise. Contact your arborists if you have any concerns that these insects may be on your landscape. Damage can occur so early in the season that by the time it is noticed, treatments will not be effective. Catalog damage seen so preparations can be made for following seasons.
Eggs of the eastern tent caterpillar can be seen prior to leaf out. Hatching of these eggs normally correlates with Forsythia blooms. Tents are already being created by larvae in mid-Atlantic states. When Forsythia is blooming in your region monitor branched forks of wild cherry, crabapple and apple trees for caterpillar tents, caterpillars feed on a variety of deciduous trees but prefer the aforementioned. Physically destroying tents will leave caterpillars open for prey by natural enemies. But foliar treatments are also effective. Contact your arborist if you see anything suspicious in your trees before damage becomes too extensive leaving trees stressed for the remainder of the growing season.