Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) was released throughout California in 2000 and 2001 to control the red-gum lerp psyllid, Glycaspis brimblecombei Moore (Hemiptera: Psylloidea). The wasp established and quickly became effective in coastal areas but to date has had less impact inland. The experiments discussed herein were designed to address this problem and to collect basic biological information that would improve the control program. The specific objectives were to determine adult longevity and fecundity, to determine host-stage preference for oviposition, and to compare parasitism in the field at inland and coastal sites. Maximum fecundity occurs at one to three weeks of age. Most eggs are recovered from 3rd instars, but oviposition is attempted into 3rd, 4th, and 5th instars equally. Observations of host-handling behavior suggest that the large lerps of 4th and 5th instars impede oviposition. In field studies conducted during the summer, adult longevity and fecundity were lower at inland than at coastal sites, suggesting that high summer temperatures inland limit the effectiveness of the wasp.