Laboratory rearing of Ooencyrtus pityocampae (Mercet) on eggs of Nezara viridula (L.) and other pentatomids

The encyrtid Ooencyrtus pityocampae is a potential biological control agent of Thaumetopoea pityocampa, a pest of pine (Pinus) in the Mediterranean Basin. Attempts were made to rear the parasitoid in the laboratory on the eggs of 9 species of pentatomid, including species not previously reported as hosts. Females of O. pityocampae emerging from T. pityocampa egg masses collected in the field accepted eggs of all 9 species: Aelia rostrata, Carpocoris sp., Nezara viridula, Dolycoris baccarum, Rhaphigaster nebulosa, Eurydema ventrale [E. ventralis], E. oleracea, Eurygaster maura and Graphosoma lineatum italicum. Successive generations of the parasitoid developed in eggs of Carpocoris sp., Eurydema ventrale, G. I. italicum and N. viridula. N. viridula has numerous advantages for use as a host compared with other species as it is easy to rear and not subject to diapause, has a high fecundity and longevity and a long embryonic development period. O. pityocampae was reared on N. viridula eggs for up to 12 generations with no apparent adverse effects on the parasitoid's fecundity, adult longevity or development time. After several generations on the alternative host, females of O. pityocampae were immediately able to accept eggs of T. pityocampa.