Aphids feed on the foliage and twigs of plants by sucking sap. There are over 350 different aphid species in Colorado and almost all plants are potential hosts. Symptoms vary depending on the type of aphid and the host plant, but include curling leaves, wilting leaves, premature defoliation and sometimes even dieback of shoots and buds. In addition to the negative impacts to your plants, aphids can be a significant nuisance due to their production of honeydew. Honeydew is the sticky waste material excreted by aphids, and it covers everything that lies beneath infested plants. Black sooty mold grows on the honeydew, which detracts from the appearance of decks, sidewalks and plants. Several predator insects feed on aphids and sometimes keep their populations in check. Unfortunately, aphids often overwhelm their natural predators during cool, wet weather. When natural controls are not sufficient, treatment options include spraying, soil injections and trunk injections.
PHOTO (middle) accredited to: W. Cranshaw, Colorado State Univ., www.Bugwood.org
PHOTO (right) accredited to: W.M. Brown, Jr., www.Bugwood.org