Little green weevils (Polydrusus weevils)
Photo: Jeff Hahn
Photo: Jeff Hahn
Some gardeners have discovered small green weevils on their plants during early May. These weevils are known as Polydrusus sericeus (no common name). Originally from Europe, P. sericeus is a type of broadnosed weevil. They get their name because unlike most weevils that have a conspicuous long slender snout, their snout is short and broad. They are about 1/4 inch long, black, and are covered with metallic green scales. When this weevil is newly emerged as an adult, it will also show some iridescent gold or red color on it. Like other broadnosed weevils, Polydrusus can not fly.
This insect was reported recently feeding on William Baffin rose in the St. Paul area and apple and pagoda dogwood in central Minnesota. This weevil is generally common through out much of northern and central Minnesota. They actually have a broad host range, feeding on the leaves of many hardwood trees and shrubs. They feed by making notches along the edge of the leaves. They are also known to attack buds.
This beetle does not usually occur in high enough numbers to cause severe damage, although it is possible for it to have a high population in a localized area. These weevils are first active in late May or June and can be found through the summer. If you encounter a situation where you would like to manage these weevil, many active ingredients should be effective against them, such as permethrin, esfenvalerate, bifenthrin, cyfluthrin, carbaryl, or acephate. Be sure to select a specific product that is labeled for the plants you wish to treat.
Published in Yard & Garden Line News, June 15, 2006