Aphids

Click on the thumbnail image for the larger photo.

	Aphids feed in colonies. They have plump, pear-shaped bodies and two tubes, or cornicles, which project like exhaust pipes from their abdomens.
	There are many species of aphids, and they feed on all types of vegetation. The white pine aphid feeds on the bark of twigs and branches of Eastern white pine. Heavy aphid infestations can seriously weaken small trees.
	Aphid colonies may be found on young leaves, new succulent shoots, and twigs or branches. Many vegetables and fruit trees, as well as ornamental plants, are attacked. This species is the green apple aphid.
	Aphid feeding often causes leaves to curl and become deformed. Once this happens, control is very difficult because aphids inside the curled leaves are protected from contact with the insecticide. Some aphids are important vectors of plant diseases.
	Aphids excrete a sugary waste produce called honeydew. Notice the clear drop on the left side of this picture. Ants, bees, and wasps collect honeydew for food. Black and brown fungi, appropriately called sooty molds, cover leaves and other objects below aphid colonies where honeydew collects. Sooty mold problems can be prevented by controlling the resident aphids. A variety of insecticides are registered for aphid control.
	Some aphids produce a protective coat of white waxy filaments. Woolly alder aphids feed and reproduce on silver maple in spring and early summer, then produce winged forms which migrate to alder to start new colonies. While not particularly injurious to either of its hosts, this aphid can become a nuisance because its white, woolly threads accumulate under heavily infested trees.
	This insect is commonly called the Hemlock Woolly Aphid even though it is not in the scientific family of true aphids. Its correct name is the Hemlock Woolly Adelgid. Underneath the wax, adelgids resemble tiny, plump aphids without cornicles.
	The pine bark adelgid is also commonly called an aphid. Similar adelgids feed on spruce, larch, and other conifers.
	Twigs, large branches, and trunks of heavily infested pine trees may become nearly white with wax from pine bark adelgids. though light infestations cause little damage, persistent heavy infestations can seriously weaken a tree and may eventually lead to its death. The same insecticides which are registered for aphid control may be used on adelgids; however, the results are not always satisfactory because their protective waxy coat reduces the amount of insecticide which reaches the insect.