Disease can strike any tree in Northeast Ohio, no matter how healthy it appears to the untrained eye. Broadly speaking, there are two categories of tree diseases:

• Infectious Diseases: These are diseases caused by microscopic organisms such as fungi, viruses, or bacteria, and which can be transmitted from tree to tree.
• Non-Infectious Diseases: These are diseases that are non-transmittable and are not caused by living organisms. Rather, they are caused by environmental stimuli such as poor soil conditions, a lack of nutrients, extreme temperatures, pollutants, excess moisture, or drought.

Unfortunately, tree diseases are often very difficult to diagnosis because most diseases cause similar symptoms (i.e., browning leaves). Because of this, a certified professional arborist is needed to diagnose and control tree disease. These experts have years of experience diagnosing illness in trees and have been extensively educated on tree biology and physiology.

In Greater Cleveland and throughout Northeast Ohio, there are hundreds of insect species that can cause damage to a tree’s leaves, branches, roots, flowers, or fruit. Insects that are harmful to trees can be divided into three categories according to how they interact with plant material:

• Chewing insects such as beetles and caterpillars eat plant tissue, including leaves, roots, flowers, and flower buds. Damage caused by chewing insects is obvious; just look for tiny notches chomped out of your tree’s leaves!
• Sucking insects such as aphids and leafhoppers suck the juice out of a tree’s leaves, branches, flowers, or fruit by puncturing surfaces with their “beak” (called a proboscis). Tree damage caused by sucking insects is subtle, and could include leaf spotting and discoloration, drooping branches, and poor vitality.
• Boring insects such as bark beetles or weevils form holes in a tree’s bark, either to feed or to lay eggs. Evidence of boring insects is readily apparent, with numerous small holes found across the bark and the presence of sawdust-like “frass,” or excrement. Boring insects can be particularly damaging, and can even prove fatal to trees.

Before you start panicking about damaging tree insects, keep this in mind: not all insects will hurt your trees! In fact, insects are a natural part of the ecosystem, and many play beneficial roles such as pollinating flowers or feeding on their more destructive peers. Instead of spraying an insecticide in your yard by yourself, consider hiring a professional. An arborist will be able to devise an insect management plan that reduces harmful tree bugs while sparing beneficial ones.