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Biocontrol introduction

Target pest: Paropsis charybdis (Coleoptera: Chrysomelidae), eucalyptus tortoise beetle

Agent introduced: Eadya daenerys (Hymenoptera: Braconidae)

Release details:

Withers, Allen et al. (2020) - the first releases are planned for 2021.

Impacts on target:

Pugh et al. (2020) - P. charybdis egg parasitism was monitored at two Eucalyptus nitens plantations in the central North Island between November 2016 and April 2017 [i.e. prior to the release of E. daenerys]. P. charybdis egg production peaked in mid‐late November and again in early February at both sites. The spring generation of P. charybdis escaped egg parasitism entirely, while the egg parasitoid Neopolycytus insectifurax provided a very useful level of control over the second generation. From November through December, there was significant defoliation of hosts by the spring generation of P. charybdis. The first appearance of early instar larvae of P. charybdis in New Zealand closely overlaps that of the appearance of adult E. daenerys in the climatically similar Tasmania. Climatic matching indicates that most of New Zealand, and importantly the major eucalypt growing areas, are a good match with Tasmania, meaning E. daenerys has all the prerequisites to permit it to establish in the major eucalypt growing regions in New Zealand and be well‐timed to make an impact upon the larvae of the first P. charybdis generation.

Impacts on non-targets:

Withers, Todoroki et al. (2020) - Eadya daenerys is most commonly associated with Paropsisterna agricola in Australia, but is proposed as a biological control agent for Paropsis charybdis in New Zealand. Host testing of E. daenerys was undertaken on nine non-target chrysomelid beetle species with spring-active, external leaf-feeding larvae that included one New Zealand native (Allocharis nr. tarsalis), six introduced beneficial weed biological control agents (Gonioctena olivacea, Chrysolina abchasica, Lochmaea suturalis, Agasicles hygrophila, Neolema ogloblini, Cassida rubiginosa), and two exotic pests (Trachymela sloanei, Dicranosterna semipunctata). Development to emergence only occurred within eucalypt-feeding pests: the target P. charybdis and another pest Trachymela sloanei (both, unlike other species tested, in the sub-tribe Paropsina). Unsuccessful internal parasitism occurred in four less closely related species (but still in the same sub-family of Chrysomelinae). Even though E. daenerys is host specific at the level of the sub-tribe Paropsina, not at the level of the genus, it is concluded it is unlikely to cause direct non-target impacts beyond pest Paropsina species in New Zealand.

Withers, Allen et al. (2020) - behavioural observations of host finding and acceptance in both no-choice and choice tests are consistent with the physiological host range proposed as the result of previous host range tests (Withers, Todoroki et al. 2020). Results indicate that E. daenerys is unlikely to attack non-target species apart from Eucalyptus-feeding invasive paropsines. Most non-target larvae were disregarded upon contact. Non-lethal negative impacts upon less preferred non-target larvae are possible if E. daenerys does attack them in the field; however, this is likely to be rare.

General comments:

Peixoto et al. (2018) - to determine which of the many paropsine beetle hosts native to Tasmania are utilised by the braconid Eadya paropsidis (the focus of recent efforts to identify host specific biological control agents from Tasmania), and to rule out the presence of cryptic species, a molecular phylogenetic approach was combined with host data from rearing experiments from multiple locations in Tasmania across six years. Eadya paropsidis was true to the type description, and was almost exclusively associated with Paropsis tasmanica. A new cryptic species similar to E. paropsidis, Eadya sp. 3, was readily reared from Paropsisterna agricola and Paropsis charybdis from all sites and all years. Eadya sp. 3 represents the best candidate for biological control of P. charybdis and was determined as the species undergoing host range testing in New Zealand for its potential as a biological control agent.

Ridenbaugh et al. (2018) - Eadya daenerys Ridenbaugh, 2018, sp. n. is described. This species (referred to as Eadya sp. 3 in Peixoto et al. 2018) is now the focus for importation into New Zealand to control P. charybdis.

Withers (2018) - A collaborative study between biocontrol scientists at Scion, the University of Tasmania and evolutionary biologists at the University of Central Florida [see above information] revealed that Eadya paropsidis, our proposed biocontrol agent to manage eucalyptus tortoise beetle, is actually a different species, E. daenerys. After careful examination, our actual species can now be separated by both physical characteristics and genetic analysis from E. paropsidis.

EPA Applications:

EPA (2014a) - 27 Jun 2014: application by Scion to import into containment a parasitoid wasp, Eadya paropsidis [subsequently determined to be E. daenerys - see General Comments section], for assessment as a biological control agent of eucalyptus tortoise beetle. EPA Application APP202154, approved with controls 8 Aug 2014.

EPA (2019a) - application by Scion to release a parasitoid wasp, Eadya daenerys, as a biological control agent for the Eucalyptus tortoise beetle (Paropsis charybdis). Application APP203631, approved without controls 25 Feb 2019.


EPA (2014a). EPA application APP202154: to import into containment a parasitoid wasp, Eadya paropsidis (Hymenoptera: Braconidae) for assessment as a biological control agent of the pest Eucalyptus beetle Paropsis charybdis, a pest of Eucalyptus trees in New Zealand. Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/APP202154

EPA (2019a). EPA application APP203631: to release from containment a parasitoid wasp, Eadya daenerys, for biological control of the pest Eucalyptus tortoise beetle, Paropsis charybdis, a pest of Eucalyptus trees in New Zealand. Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/APP203631

Peixoto L, Allen GR, Ridenbaugh RD, Quarrell SR, Withers TM, Sharanowski BJ. (2018). When taxonomy and biological control researchers unite: Species delimitation of Eadya parasitoids (Braconidae) and consequences for classical biological control of invasive paropsine pests of Eucalyptus. PLoS ONE 13(8): e0201276 https://doi.org/10.1371/journal.pone.0201276

Pugh AR, Withers TM, Peters EM, Allen GR, Phillips CB. (2020). Why introducing a parasitoid of Paropsis charybdis Stål, 1860 (Coleoptera: Chrysomelidae) larvae is expected to enhance biological control of this Eucalyptus pest in New Zealand. Austral Entomology 59(4): 829-837 https://doi.org/10.1111/aen.12492

Ridenbaugh RD, Barbeau E, Sharanowski BJ. (2018). Description of four new species of Eadya (Hymenoptera: Braconidae), parasitoids of the Eucalyptus tortoise beetle (Paropsis charybdis) and other Eucalyptus defoliating leaf beetles. Journal of Hymenopteran Research, 64: 141-175

Withers TM, Allen GR, Todoroki CL, Pugh AR, Gresham, BA. (2020). Observations of parasitoid behaviour in both no-choice and choice tests are consistent with proposed ecological host range. Entomologia Experimentalis et Applicata. Special Issue: 6th International Entomophagous Insects Conference 1–14

Withers TM, Todoroki CL, Allen GR, Pugh AR, Gresham BA. (2020). Host testing of Eadya daenerys, a potential biological control agent for the invasive chrysomelid pest Paropsis charybdis, predicts host specificity to eucalypt-leaf feeding Paropsina. BioControl 65(1): 25-36. Published online: 02 November 2019. https://doi.org/10.1007/s10526-019-09978-6

Withers TM. (2018). Introducing Eadya daenerys, "mother of all dragons". Forest Health News No. 282, July 2018. Scion forest health newsletter. https://cdm20044.contentdm.oclc.org/digital/collection/p20044coll2/id/207/rec/1