Figure 11. Norway maple aphid eggs hidden around the base of shoots. Photograph courtesy of Ken Gray Collection, Oregon State University.
Adult (a) and larva (b) of a female beetle.
Adult (a) and larva (b) of a female beetle.
Figure 12a-b: Adult (a) and larva (b) of a female beetle.
Green cord larvae
flower fly
Figure 13a-b: Larvae of a green string fly (as) and a flower fly (b).
Adult parasitoid wasp next to database d two aphid mummies.
Figure 14: Adult parasitoid wasp next to two aphid mummies.
Aphids are fairly defenseless and there are numerous insects that feed on them (Fact Sheet 5.550, Beneficial Insects and Other Arthropods). The best known of these natural enemies are female beetles, with female beetle larvae being particularly voracious predators of aphids. Other common aphid predators include the larvae of green swarms and flower flies (sirphids).
Several species of tiny stingless wasps parasitize aphids. These parasitoid wasps insert their eggs into the body of the aphid and the larvae consume it internally. Aphids that have been killed by parasitoid wasps ("aphid mummies") have a striking appearance, becoming swollen, light brown or black, and sticking to the plant.