Aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) of Northwest USA

A comprehensive assessment is provided of the Northwest USA aphid-parasitoid species (Hymenoptera, Braconidae, Aphidiinae). Eighty-one species of parasitoids in 19 genera are recognized; 35 species are new to the region; 7 species are newly described: Aphidius segmentatus Pike and Start [hosts: Hyperomyzus on Hieracium, Lactuca, Senecio, and other Compositae, and on Uroleucon on Achillea]; Betuloxys abnicolus Pike & Start [host: uncertain, possibly Boernerina variablilis Richards on Alnus]; Monoctonus campbellianus Pike & Start [hosts: Brachycaudus, Hyalopterus, and Phorodon on Prunus]; Monoctonus pacificus Pike & start [host: Macrosiphrum tuberculaceps (Essig) on Achlys triphylla]; Praon coniforme Pike & Start [host: Aphthargelia symphoricarpi (Thomas) on Symphoricarpos]; Praon fulvum Pike & Stary [hosts: Macrosiphum spp. on Achlys, Crepis, Lupinus, Spiraea]; Trioxys setaceus Pike & Start [host: Acyrthosiphon macrosiphum (Wilson) on Amelanchier]. Seventy genera of aphids (200+ spp.) were attacked by aphidiine parasitoids. Some 400+ parasitoid-aphid associations, and hundreds more tritrophic (parasitoid-aphid-plant) combinations are reported for the first time in North America.