Potential of Selective Insecticides for Managing Uraba lugens (Lepidoptera: Nolidae) on Eucalypts

Abstract The leaf skeletonizer Uraba lugens Walker (Lepidoptera: Nolidae), an Australian species, locally known as “gumleaf skeletonizer,” is well established in New Zealand. This insect has the potential to become a serious pest of forestry and amenity eucalypts (Eucalyptus spp.) and is the focus of a long-term management program. The use of synthetic chemical or biological insecticides is one possible control method within an integrated control program. A series of dose–response trials were conducted using laboratory bioassays to test the efficacy of several insecticides against U. lugens: pyrethroids, spinosad, Bacillus thuringiensis kurstaki Berliner (Btk) and an insect growth regulator, Mimic. Pyrethroids and spinosad proved highly effective against U. lugens larvae, achieving 100% mortality after 3–6-d exposure. The performance of Btk was lower against gregarious skeletonizing larvae compared with solitary chewing larvae. When good coverage of the target foliage is achieved, >90% mortality is possib...