Potential of selective insecticides for managing Uraba lugens (Lepidoptera: Nolidae) on Eucalypts.
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 possible with Btk. Mimic performed poorly against U. lugens compared with other insecticides tested (<60% mortality). The Eucalyptus species on which larvae were feeding significantly altered insecticide efficacy. Treatments applied to Eucalyptus nitens (Deane & Maiden) Maiden had reduced efficacy compared with E. cinerea F. Muell. ex Benth. or E. fastigata Deane & Maiden. Cooler temperatures also reduced insecticide efficacy, presumably by decreasing movement and food consumption by U. lugens. Recommendations on spray applications to control U. lugens in New Zealand are given.
Mansfield
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Forest Biosecurity and Protection, Ensis, PB 3020, Rotorua, New Zealand.
Withers
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TM
Gous
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Potter
K J B
KJ
Kriticos
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DJ
Watson
M C
MC
Kimberley
M O
MO
D000818:Animals; D001413:Bacillus thuringiensis; D004338:Drug Combinations; D005052:Eucalyptus / Q000469:parasitology*; D006790:Host-Parasite Interactions; D006834:Hydrazines; D007306:Insecticides; D007605:Juvenile Hormones; D018942:Macrolides; D009036:Moths; D010572:Pest Control, Biological; D011722:Pyrethrins; D013696:Temperature
D004338:Drug Combinations; D006834:Hydrazines; D007306:Insecticides; D007605:Juvenile Hormones; D018942:Macrolides; D011722:Pyrethrins; C082026:tebufenozide; C415329:spinosad