Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Many species are green but other commonly occurring species may be white and wooly, brown, or black. Aphids are among the most destructive insect pests on cultivated plants in temperate regions. They are capable of extremely rapid increase in numbers by asexual reproduction. The damage they do to plants has made them enemies of farmers and gardeners around the world. From a zoological standpoint they are a highly successful group of organisms.