Phenology, synchrony and host range of the Tasmanian population of Cotesia urabae introduced into New Zealand for the biocontrol of Uraba lugens

The population dynamics of <i>Cotesia urabae</i> (Austin and Allen) (Braconidae: Microgastrinae), a biological control agent from Tasmania, and its eucalypt feeding host, <i>Uraba lugens</i> (Walker) (Lepidoptera: Nolidae) was investigated prior to its introduction to New Zealand in 2011. Previous host range testing on potential New Zealand non-targets determined <i>C. urabae</i> had some potential to attack an endemic species, <i>Nyctemera annulata</i> (Boisduval) (Lepidoptera: Arctiidae). A closely related species in Tasmania, <i>Nyctemera amica</i>, was thus investigated as a potential host along with the native host <i>U. lugens</i>, to better understand the host range of <i>C. urabae</i> and the synchrony with its host in Tasmania. Adult <i>C. urabae</i> emerged from pupal cocoons in the field during January which confirmed a five month window in which its host, the larvae of <i>U. lugens</i>, was absent in the field. Experiments using sentinel <i>N. amica</i> and <i>U. lugens</i> larvae, field collections of <i>N. amica</i> and of larvae of other Lepidopteran species during this five month time window detected no parasitism by <i>C. urabae</i>. In the laboratory, host specificity testing showed reduced attack rates and no resultant <i>C. urabae</i> eggs or developing larvae or any successful pupation of <i>C. urabae</i> larvae from attacked <i>N. amica</i> larvae. It was concluded that <i>N. amica</i> is most unlikely to be a host for <i>C. urabae</i> in Tasmania and no evidence of any other alternative host was found.