Answer: Several species of borers attack dogwoods by tunneling under the bark. Signs of borers include swollen areas on the trunk, usually just above or just below soil line. You may also see some sawdust-like material around the holes or on the ground underneath the holes.
Since you've found some holes, you may indeed have borers. (As you probably know, some birds such as woodpeckers and sapsuckers can also make holes in the trunk.) Borers can be difficult to control, since they are hidden inside the trunk. Some people have good luck by sticking a thin wire (an unfolded paper clip will do) into the hole to pierce the larva.
Other possible causes of thy symptoms include aphids, which cause leaves to become curled and distorted. Look for clusters of these small insects, especially on new leaves and on the undersides of leaves. There are also some diseases, notably anthracnose, which is causing trouble with dogwoods throughout the northeast.
Dogwoods prefer dappled shade to harsh, direct sun. They need lots of water and prefer a moist, woodland soil. Could your tree be suffering from a lack of water and/or too much sun?
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