Aphids are small insects that feed on sap by using their piercing and sucking mouths, referred to as a stylet. While most are wingless, at certain times of the year, some females may be born with wings when food supply is low to find more. Most species of aphids are monophagous, which means they feed on one species of plants, however there are others that can feed on hundreds of plant species.
Aphids are on of the most destructive pests on plants in temperate climates. They start by weakening the plant by sucking out its sap and can spread plants viruses very quickly. A heavy infestation is easy to identify because the infested leaves can turn yellow or wilt away. The waste produced by aphids is called honeydew, it is a sugary liquid that can easily transfer onto windows or cars, and when accumulating on branches and leaves, can turn them black as a fungus develops in thick places.