Aphids are piercing-sucking insects which includ a vast number of species. They have various shapes, colors and sizes but are usually small, soft-bodied and pear-shaped with long, thin legs. Aphids are often found feeding in large groups and are slow-moving. They give off a sticky substance called “honeydew” which will often cover objects below. Aphids do damage when populations become high. Damage will consist of leaves becoming curled, distorted and/or yellow and growth of the tree will be stunted.