Aphids

Characteristics

Aphids are small, pear-shaped insects with long antennae and a pair of cornicles that stick out on either side of their stomach. They often have opaque bodies and are usually green, red, black, yellow, or white. There are hundreds of species of aphids that have been discovered.

Aphids damage trees by sucking the sap from leaves, twigs, stems, and roots. While feeding, they secrete a liquid called honeydew (a sweet sap) which attracts other pests like ants, flies, and wasps. The honeydew they produce can also cause trees to develop black sooty mould, making leaves appear dirty and grey.

A colony of aphids can grow very quickly. To keep plant damage to a minimum, it is important to control aphid infestations sooner than later.

Signs & Symptoms

Aphid damage is easiest to spot on ornamental, fruit, and shade trees. Aphid colonies tend to reside on the parts of plants with softer tissue such as leaves and the tips of branches.

Infested leaves will have spotty yellow discolouration and may dry out, wilt, or curl. Aphids may cause leaves to form galls (swellings of plant tissues that are globe or spindle-shaped). The galls, which often turn brown, contain many aphids in all stages of development. When aphids molt, they cast off their skins, which look like small white flakes.

Treatment & Recommendations

Aphids don’t cause severe damage to trees and shrubs. Infested sections of trees and shrubs can be pruned off, or treated with insecticides.

If you are experiencing aphid problems talk with one of our qualified arborists.