Canadian Forest Service Publications

Multiple effects of tebufenozide on the survival and performance of the spruce budworm (Lepidoptera: Tortricidae). 2017. van Frankenhuyzen, K.; Régnière, J. Can. Entomol. 149: 227-240.

Year: 2017

Available from: Laurentian Forestry Centre

Catalog ID: 37394

Language: English

CFS Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.4039/tce.2016.50

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Aerial application of Mimic® 2LV to rising outbreak populations of the spruce budworm (Choristoneura fumiferana (Clemens); Lepidoptera: Tortricidae) in Québec, Canada, resulted in high levels of population reduction at spray deposits of 0.5–1.2 μg tebufenozide/g of foliage. Application to potted host trees in outdoor enclosures followed by bioassays revealed multiple effects on spruce budworm survival and recruitment. Chronic (14-day) exposure of late-instars to treated foliage reduced larval survival and also pupal survival, mating success, and fecundity, depending on the product concentration applied. Treatments that produced foliar deposits of 0.5–1.5 μg tebufenozide/g caused high larval mortality. Exposure to deposits of 0.15–0.5 μg/g caused delayed mortality during the pupal stage and reduced the mating success of survivors, while exposure to ~ 0.07–0.15 μg/g reduced the fecundity of mated females. Sublethal exposure did not affect the progeny of survivors, either in egg hatch, survival during diapause, or survival and performance after diapause. Reduced survival during late-larval and pupal stages combined with lower recruitment as a result of reduced mating success and fecundity are likely to play a role in the suppression of Mimic®-treated spruce budworm populations in the years following treatment.

Plain Language Summary

In this study, the researchers tested the effect of exposure to different doses of Mimic® 2LV on spruce budworm (SBW) larvae. Mimic® is an insecticide that affects the hormonal system, causing a premature, incomplete and lethal molt in larvae. Once the SBW larva has ingested the insecticide, it temporarily stops eating.

Fourteen days of exposure to foliage treated with Mimic® reduced the survival of older larvae and pupae. It also decreased the rate of successful mating and fecundity among surviving insects. If there is enough Mimic® on the foliage, delayed mortality is observed during pupation as well as a decreased rate of successful mating among surviving insects and lower fecundity in mated females.

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