Title: Susceptibility of the endangered Karner blue butterfly (Lepidoptera: Lycaenidae) to Bacillus thuringiensis var. kurstaki used for gypsy moth suppression in Michigan
Author: Herms, Catherine Papp; McCullough, Deborah G.; Bauer, Leah S.; Haack, Robert A.; Miller, Deborah L.; Dubois, Norman R.;
Source: The Great Lakes Entomologist 30(4):125-141
Publication Series: Scientific Journal (JRNL)
Description: We investigated the phenological and physiological susceptibility of the endangered Karner blue butterfly (Lycaeides melissa samuelis) to Bacillus thuringiensis var. kurstaki (Bt), a product widely used for gypsy moth (Lymantria dispar) suppression in Michigan and other infested states. We monitored phenology of the bivoltine Karner blue in two regions of Michigan from 1993 to 1995 to determine if larval stages overlapped temporally with the period of Bt application for gypsy moth suppression. Karner blue larvae of the spring generation were found during the period that Bt was applied in nearby areas in 1993 only. However, spring-generation adults or newly laid eggs were observed up to 11 days before applications in 1994 and 1995. Since Karner blue eggs develop within one week, summer-generation larvae were most likely present during or shortly after 1994 and 1995 Bt application periods. These larvae would have been at risk, assuming Bt persistence of 4 to 6 days. Physiological susceptibility of Karner blue larvae to Bt was determined in a laboratory bioassay. Larvae were reared on wild lupine (Lupinus perennis) foliage that was untreated, or sprayed with Bt formulations at rates of 30-37 or 90 BIU/ha. A similar bioassay with second instar gypsy moth larvae on similarly treated white oak (Quercus alba) foliage was conducted concurrently. Karner blue survival was 100%, 27% and 14% on control, low and high Bt treatments, respectively. Early and late Karner blue instars were equally susceptible to Bt. Survival of gypsy moth was 80%, 33% and 5% on control, low and high Bt treatments, respectively, and did not differ significantly from Karner blue survival. We conclude that Karner blue is both phenologically and physiologically susceptible to Bt used for gypsy moth suppression, although the larval generation at risk and extent of phenological overlap may vary from year to year.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
- This publication may be available in hard copy. Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact Sharon Hobrla, firstname.lastname@example.org if you notice any errors which make this publication unusable.
XML: View XML
Herms, Catherine Papp; McCullough, Deborah G.; Bauer, Leah S.; Haack, Robert A.; Miller, Deborah L.; Dubois, Norman R. 1997. Susceptibility of the endangered Karner blue butterfly (Lepidoptera: Lycaenidae) to Bacillus thuringiensis var. kurstaki used for gypsy moth suppression in Michigan. The Great Lakes Entomologist 30(4):125-141
Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility