In Egypt. Z pyrina is a serious polyphagous pest in fruit and wood trees. Larvae were reared on its natural hosts (apple, pear, pomegranate and olive) as well as on artificial medium diets, each containing saw dust of one of the previously mentioned hosts. Number of larvae and pupae completed their development, percentage of pupation, larval and pupal durations, rate of moth emergence, mating, oviposition, longevity, incu­bation period and percentage of hatchability were studied in details on natural hosts and artificial medium diets. The approximated life cycles were 336.7 (318 - 370), 344.8 (337 - 367), 328.7 (321 - 360) and 377.3 (366 - 398) days on natural hosts and 126.0 (121 — 137). 132.8 (123 — 146), 136.3 (126 - 158) and 144.1 (141 - 162) days on artifi­cial medium diets when reared on apple. pear, pomegranate and olive, re­spectively.Out of 100 eggs each reared on their natural hosts (apple, pear, pomegranate or olive) were 20,24,18 and 20% completed their de­velopment to adult moths.Tho percentage recovery when reared on the respective artificial diets were 68, 58, 64 and 61%. Rearing Z. pyrina on artificial diets reduced the total period of the life cycle with about 2/3 than rearing on their natural hosts .