The black bean aphid has alternate hosts. In early April the winged aphids fly to their summer hosts, infesting a wide range of different plant species, for example, beans, potatoes, beets. Egg deposition then takes place on the winter hosts.
Bean aphid [Aphis fabae]
Bean aphid - image 1
The Aphids are approx. 1.5 mm to 3.0 mm in size, dull black to dark green. The legs are light with dark tips. Black bean aphids form dense colonies on growing tips and the underside of leaves (Picture 1).
Pattern of damage
Rolling of the leaves and distortion of the growing tips are typical. Sooty mold may then colonize the honeydew excreted by the aphids.