Devoured and skeletonized leaves are indicative of a Japanese Beetle infestation. Swarms of the insect attack their host, eating as they go. Favorite hosts include Rose bushes, Linden trees, flowering Crabapple and Cherry trees, Viburnum bushes, Elm trees, Japanese Maple trees, plus many other trees and shrubs. In the Chicago area, the adult Japanese Beetles usually appear around the beginning of July and feed for about 30-45 days before laying eggs and dying. The Japanese Beetle usually does not cause permanent damage to the tree or shrub, unless the plant is enduring infestations year after year. Aesthetically, the host tree or shrub is compromised. Leaves have a “lacy” appearance after the Japanese Beetles have finished feeding and are not as attractive.
Control methods are varied. Some homeowners choose to knock the Japanese Beetles off the host plant into a pail of soapy water or alcohol. This will kill the insect. For larger infestations or on large trees, an insecticide may be necessary to control the insect. Kramer Tree Specialists offers an insecticide spray that kills the Japanese Beetle on contact. The insect must be present to be effective. In addition, KTS offers an option to inject the soil around the host with an insecticide that will kill the Japanese Beetles when they begin feeding on the tree or shrub. This option must be done in early spring or late fall for optimal effectiveness. Overall feeding damage can be minimized if control is implemented when the Japanese Beetle first arrives.
Noticing Japanese Beetles on your trees and shrubs? Contact the Plant Health Care Department at KTS for more information on scheduling an insecticide spray for immediate Japanese Beetle control.