Aphids USDA Forest Service Forest Health Protection, Southern Region Aphids Importance. They can be found almost anywhere on a tree, particularly on new growth. Heavy infestations distort foliage, cause terminal dieback, reduce tree vitality, weaken the tree, and cause branch and crown dieback. In young trees and seedlings, mortality can occur from heavy infestations.
Aphids are usually of greatest concern in nurseries, seed orchards, and shade and ornamental trees.
Honeydew and sooty mold, associated with aphids, usually mar the beauty of ornamentals. Identifying the Insect. However, they are all soft-bodied insects. Most aphids are pear-shaped, with a pair of cornicles at the posterior of the abdomen. They may be transparent, yellow, green, pink, brown, almost black, or spotted.