Oak-stem Borer

An oak stem borer actually looks similar to a grasshopper but they can blend in with their surroundings. These bugs that eat oak trees particularly like the smaller branches at the tops and sides of oak trees because here they can ‘bore’ into the smaller twigs where its easier to go through to the trunk and into an oaks root collar. They can cause quite a bit of damage that results in brown foliage and dead branches in the are of an oak they have impacted. 

Forest Tent Caterpillar

These caterpillars are very easy to spot because they are brown in color and have very distinct lines running the length of their bodies. They also have keyhole-shaped spots on their backsides. They are predominantly found eating oaks and other hardwoods in the Eastern USA. The first sign of these insect’s presence is the thinning of foliage at the top of an oak tree. Although these bugs that eat oak trees do not usually kill oak trees unless they attack several years in a row, they will impact a tree’s growth by causing die-back. 

Two Lined Chestnut Borer

Here is another grasshopper looking oak tree predator. They are usually brown or dark green in color. As the name implies, they have two stripes that run side by side the entire length of their bodies. They are known to make winding trails in the bark throughout an oak tree. Often this starts toward the top of the tree. It’s an insect that seems attracted to oaks that have started to lose their foliage because they are unhealthy or have been affected by other insects. 

Gypsy Moth

This example of an experiment gone wrong has severely hurt oaks and other trees in the northeastern USA and elsewhere. Gypsy moths were first brought into the country in an attempt to derive silk from them. Even though that proves fruitless, some of these hardy moths survived and now wreak havoc wherever they grow. The defoliation that their larvae cause results in reduced growth, loss of health, and early death of oak trees.