Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2000
Publication Date: September 1, 2002
Citation: Hight, S.D. 2002. Host specificity and risk assessment of Heteroperreyia hubrichi, a potential classical biological control agent of christmasberry (Schinus terebinthifolius) in Hawaii. Proceedings of a Workshop on Biological Control of Invasive Plants in Native Hawaiian Ecosystems, Technical Report 129. p. 29-43. Technical Abstract: Heteroperreyia hubrichi, a foliage feeding sawfly of Schinus terebinthifolius, was studied to assess its suitability as a classical biological control agent of this invasive weed in Hawai'i. No-choice host-specificity tests were conducted in Hawaiian quarantine on 20 plant species in 10 families. Adult females oviposited on four test species. Females accepted the Hawaiian native Rhus sandwicensis as an oviposition host equally as well as the target species. The other three species received dramatically fewer eggs. Neonate larvae transferred onto test plants successfully developed to pupae on S. terebinthifolius (70% survival) and R. sandwicensis (1 % survival). All other 18 test plant species failed to support larval development. A risk assessment was conducted to quantify the suitability of non-target plants as a host to H. hubrichi on the basis of the insects' performance at various stages in its life cycle. Risk to all plant species tested was insignificant except R. sandwicensis. Risk to this native plant relative to S. terebinthifolius was estimated at 1 %. Currently this is too high a risk to request introduction of this insect into the Hawaiian environment. Detailed impact studies in the native range of S. terebinthifolius are needed to identify the potential benefit that this insect offers. Also, field studies in South America with potted R, sandwicensis would give more reliable analysis of this plants risk from natural populations of H. hubrichi.