Exploring potential nontarget impacts of spinetoram against beneficial natural enemies of <i>Eucalyptus</i> forests

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Forest Stewardship Councilcertified Eucalyptus nitens plantations are seeking an alternative insecticide that is more compatible with biological control agents than the current broadspectrum insecticide used Various methods were trialled for evaluating spinetoram on beneficials including Enoggera nassaui an egg parasitioid of Paropsis charybdis Cleobora mellyi a predatory ladybird and Cotesia urabae a larval parasitoid of Uraba lugens While eggs could be directly sprayed very mobile larvae and adults instead had to be transferred onto recentlysprayed foliage For ladybirds the assay environment was supplemented with an artificial diet to avoid mortality from starvation These practical challenges limit the ability to confidently draw conclusions about impacts in the field Despite the limitations it can be reported that C mellyi suffered no mortality from exposure to spinetoram and females continued to lay viable eggs In contrast the endoparasitoid C urabae did not survive spinetoram treatment due to the rapid mortality of its host Both P charybdis eggs and their parasitoids developing within them appeared unharmed by spinetoram These mixed results suggest spinetoram does have potential as a possible replacement for alphacypermethrin although further investigation of efficacy in the field is needed