Host range testing for risk assessment of a sexually dimorphic polyphagous invader, painted apple moth.
A wide known host range in Australia and novel herbivory on native and naturalized species in New Zealand supported the decision to commence a NZ$65 million eradication programme against painted apple moth [Teia anartoides (Walker) (Lepidoptera: Lymantriidae)] in Auckland (1999-2007). Laboratory no-choice tests were designed to examine the 'host' status of the associations seen in the field. Laboratory tests investigated 79 native and introduced plant species with 122 provenances. Forty-two percent of plants were capable of supporting larval development to adulthood, with male bias; 30% were defined as potential hosts with female larvae developed through to the pupal stage; >10% survival indicated probable physiological hosts. Sporadic or more frequent attack of New Zealand native broom, and introduced lemon, apple, sycamore, walnut, cherry and poplar, was likely, with a wider range of hosts supporting male emergence. A few negative laboratory results contradicted field observations of significant damage by large numbers of larvae. The present study highlights the challenge faced with respect to predicting the ecological host range of invasive polyphagous species, whose biology is little known, during the early stages of a first invasion. The implications of a wider host range found in males than females are discussed.