Eucalyptus variegated beetle: genetic diversity of New Zealand and Australian collections

Paropsisterna variicollis, the eucalyptus variegated beetle, was first detected in New Zealand in 2016. It threatens a growing eucalyptus forestry sector through larvae and adults causing significant defoliation to important plantation species. This work aimed to clarify the identification and origin of the New Zealand incursion to inform selection of suitable biological control agent(s). Australian and New Zealand specimens from the Paropsisterna obovata-variicollis-cloelia species complex were analysed by PCR and sequencing of two genetic loci, cytochrome c subunit I (COI) and cytochrome b (Cyt b). Molecular analysis of both genetic regions showed three major clusters of diversity. Cluster 1, proposed as Paropsisterna variicollis, had maximum 1.3% genetic variation and was collected from New Zealand, Western Australia and from geographically diverse locations in eastern Australia. Taxonomic results identified distinctive phenotypes of other closely related beetle species, assisting in proposing Cluster 2 as Paropsisterna near decolorata and Cluster 3 as Paropsisterna agricola. Molecular results were compared to morphological structures on adult beetles.

Investigating the potential of Eadya paropsidis (Braconidae) from Tasmania as a biocontrol agent for Paropsis charybdis in New Zealand

Despite considerable efforts the eucalyptus tortoise beetle Paropsis charybdis continues to defoliate Eucalyptus nitens plantations throughout New Zealand preventing expansion of this forest resource or requiring constant management through aerial insecticide application A parasitoid wasp of the springtime larval stage of the eucalyptus leaf beetle Paropsisterna agricola (Chapuis) (Chrysomelidae) in Tasmania is being investigated as a potential biological control agent for New Zealand The potential agent Eadya paropsidis Huddleston and Short (Braconidae) was caught as adults on the wing from E nitens plantations in northern Tasmania and brought into the laboratory in Hobart for preliminary host specificity testing Using a sequential nochoice test method to examine the response of individual females 9 of the 10 female parasitoids attacked P agricola while 7 of those 9 attacked P charybdis larvae Those P charybdis larvae that were attacked proved to be a highly suitable physiological host for E paropsidis development emerging as a larger sized parasitoid larva from P charybdis than from P agricola This potential agent will be further evaluated in a collaborative project with New Zealand eucalyptus growers and the Sustainable Farming Fund