Aphids are the most common insect that can be found on trees, shrubs, as well as garden plants. There are over 350 aphid species, most only feed on specific plants. With so many species of aphids, nearly all the plants grown in Colorado support at least one of the aphid species. Most aphid species do not permanently injure plants, but a few can cause problems. Aphid control is important for preventing large amounts from coming back.
Aphids feed by sucking the sap out of plants. Plants that have a high number of aphids for long periods of time can cause wilting, buds and shoots can die back, and some can also cause leaf curling.
One of the main concerns when aphids infest a plant involves their production of honeydew, which is their waste material. This sticky substance can cover leaves, branches, sidewalks, and also anything on or beneath the infested plant. With the production of honeydew comes the growth of a gray mold, which affects the appearance of the plant. Other insects, such as yellow-jacket wasps, flies, as well as bees are attracted to plants affected with honeydew.