Adults may be wingless or have two pairs of delicate, transparent wings. Many aphids may be recognized by a pair of tubes, known as cornicles, that project backward from the dorsal surface of the abdomen. The different species vary in color from green, yellow, gray,m red-brown, to black.
Some species secrete a white powdery or waxy, woolly material that completely covers the body.
They attack any part of the tree, sucking the sap or juices from the foliage and tender young growth. Some species may infest buds, blossoms, fruits, roots, or bark depending on the species of aphid and the plant involved. All the common hardwoods and softwoods are subject to attack. Under favorable conditions aphids multiply rapidly and appear suddenly in great numbers. Fortunately, populations fluctuate from year to year and from place to place due to natural controls.