Studies With Whitefly Parasites of Southern California: II.Eretmocerus californicusHoward (Hymenoptera: Aphelinidae)

Eretmocerus californicusis a solitary parasite of numerous whitefly species. It is able to develop in all nymphal stages of its host but prefers the second and third. Oviposition and development of the first-instar larva take place under the host, the following two instars develop endoparasitically. Superparasitism is common under artificial conditions, but the supernumeraries are always eliminated during their first or second instar. Adult longevity is highest at 60° and lowest at 100° F. Males are rare and superfluous in Riverside but abundant and essential in Indio. In Riverside,E.californicusis most abundant during the late summer and is almost absent from the field between January and June. In Indio, it is present the year around. Although it attacks the same host instars asEncarsia pergandiellaHoward, no hyper- or multiple-parasitism takes place.E.californicusis an important controlling factor on whiteflies in the Coachella and Imperial valleys but not in Riverside and the coastal area.