There are several biological control options for greenhouse aphid pests. Some common biological control agents (BCAs) include green lacewings (Chrysoperla carnea, C. rufilabris, Chrysopa spp.), aphid midges (Aphidoletes aphidimyza), parasitic wasps (Aphidius colemani and Aphidius matricariae) and lady beetles (Hippodamia convergens). See Appendix 1: Beneficial Organisms for more BCAs and suppliers.
A 1998 study showed that green lacewing larvae did not disperse as well as the parasitic wasp Aphidius colemani.(3) To achieve equal aphid suppression, more of the slower-moving species need to be introduced and from more points (lacewings have to be released on each bench because they cannot move to adjacent benches, for instance). A study performed at Colorado State University compared the effectiveness of parasitic wasps, aphid midges, lady beetle larvae, and green lacewing larvae.(4) The researchers found that lacewings performed better in hot temperatures, while aphid midges and lady beetles were better in cooler temperatures. At all temperatures, Aphidoletes was the best of the four at controlling aphids.