Biology of Trichogramma ostriniae (Hym.: Trichogrammatidae) reared on Ostrinia nubilalis (Lep.: Pyralidae) and survey for additional hosts

Trichogramma ostriniae has been identified as a candidate for biological control of Ostrinia nubilalis. As little was known about the biology of this parasitoid when reared on O. nubilalis, we undertook experiments to quantify biological parameters important to mass-rearing and use of T. ostriniae. When reared continuously on O. nubilalis, female T. ostriniae on average lived 2.7 days and produced 24 progeny. Continuous access to honey resulted in a four-fold increase in longevity and fecundity and a significant increase in the percentage of females parasitizing eggs. Rates of fecundity and parasitism decreased with age of female. Likewise, emergence rates and percentage of female progeny decreased with age of parental female. I: ostriniae successfully parasitized O. nubilalis eggs until the blackhead stage. Most parasitism of eggs and eclosion of adults occurred during the first half of photophase. Eggs of 13 Lepidopterans were parasitized by T. ostriniae. Eggs of the Noctuidae, Pyralidae, and Plutellidae experienced higher levels of parasitism than others tested. T. ostriniae appears to be similar to other species of Trichogramma in several respects and does not possess any characteristics that limit its potential for mass rearing and use for augmentative biological control of O. nubilalis.