Illinois is home to two species of the Oystershell Scale, the brown and the gray Oystershell Scale. While this pest is found in many states, northern areas are hit harder than southern states. Because of the size and color of this pest, it blends into the environment, delaying detection and allowing heavier infestations to occur. Oystershell Scale are about 1/8 of an inch long and are often the same color as the bark of the host tree or shrub. Discovery by the homeowner may not happen until the pests’ feeding has caused branch loss. This pest sucks the plant sap of their host and attaches themselves to the bark or twigs of the tree or shrub. If left untreated, Oystershell Scale can cause the decline and death of an infected tree.
Favorite hosts of the Oystershell Scale include a variety of commonly used trees and shrubs. This includes, but is not limited to Lilacs and Dogwood shrubs, Crabapple, Green and White Ash and Silver Maple trees. This pest is appropriately named due to the hard, outer covering that resembles an oyster shell. This armor protects the insect and makes it harder to eliminate.
It’s important to properly time any chemical applications when the insect is most vulnerable. This is before or during insect egg hatch, which occurs in the spring. Once the Oystershell Scale has grown its’ waxy outer covering, it is much more difficult to eliminate. Learn more about Oystershell Scale through our Pest Control page. If you suspect an Oystershell Scale infestation, contact the Plant Health Care department at KTS. We can properly identify and suggest treatment options for your trees and shrubs.
PHC Department, Mylane Bryant