Leafcurl Aphid Damage on Ash
Dozens of species of aphids (plant lice) may be found on shade trees and woody ornamental plants in Colorado. Aphids are small insects, typically less than 1/8 inch, although some may be almost 1/4 inch long. One common group, woolly aphids, produces an abundance of flossy, waxy threads that cover their bodies. Aphids feeding on developing leaves can produce leaf curl injuries. This is most frequently observed on snowball viburnum, honeysuckle, plum and ash.
When natural enemies (lady beetles, green lacewings, syrphid flies and small parasitic wasps) are not abundant enough to provide aphid control, insecticides sometimes are needed to prevent plant injury. For most aphid problems, particularly those associated with leaf curls, insecticides that move systemically within the leaf or plant provide the best control. The most common systemic insecticide available to homeowners is Orthene (acephate).
Photos: Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010