Black bean aphid  (Aphis fabae)

Description

Although sometimes called ‘blackfly’, the black bean aphid is actually a true bug (a member of the order Hemiptera). All true bugs are united by the possession of specialised piercing and sucking mouthparts, which are used in this species to obtain plant juices (3). It is this characteristic, coupled with its prolific reproductive capabilities that has made the species a notorious enemy of farmers and gardeners alike (3). This widespread aphid is a minute species with a small head and bulbous abdomen(4). The body is blackish or dark green in colour (2) and the membranous wings are held angled over the body (like a roof) when at rest. Not all individuals possess wings, and the wingless forms have squatter bodies than winged specimens (2). Two tube-like protrusions at the rear of the abdomen, known as cornicles, are the openings of wax glands. This wax protects the aphid from certain predators (4).

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