North Central Research Station

Leonora S. Bauer

My primary interests in entomology are bacteria, fungi, viruses, protozoans, and nematodes that cause insects to become sick and die, thus stabilizing insect population densities within somewhat tolerable limits. Initially, I studied the effects of insect pathogens in native forest insects. However, with recent discoveries of invasive insects killing trees in North America, my research is increasingly directed toward the development of methods to control invasive forest insect pests using insect pathogens.

Native and exotic invasive insect pests can degrade the environment by killing trees, reducing productivity, and/or limiting regeneration. Insect pathogens are useful for management of insects as biological control agents or as formulated into microbial insecticides. Insect pathogens are suitable for use in forested ecosystems because they occur naturally in the host environment, are relatively host specific, and biodegradable; some pathogens become established in insect populations and require no further action. These factors reduce the risk to nontarget organisms, limit damage within acceptable limits, and may reduce or eliminate the costs of managing an insect pest.

• Completing natural enemy survey of Asian longhorned beetle in the U.S. and China.
• Characterizing Beauveria bassiana isolates from native cerambycids.
• Describing a new species of microsporidium isolated from Asian and citrus longhorned beetles collected in China.
• Completing a 1-yr natural enemy survey that includes the parasitoids, predators, and pathogens attacking emerald ash borers in Michigan.
• Studying the efficacy of two registered microbial insecticides, Bacillus thuringiensis and Beauveria bassiana, to control the emerald ash borer.
• Development of an artificial diet to rear emerald ash borer and other buprestid in the laboratory for research on natural enemies.

• Studied microsporidian pathogens of several native insects, including discovery and description of a new species that infects the cottonwood leaf beetle.
• Discovered the efficacy of Bacillus thuringiensis (Bt) isolates and toxins, and described mechanisms of toxicity and physiological factors affecting activity in coleopterans.
• Selected cottonwood leaf beetles with resistance to the Bt Cry3A and evaluated other toxins for cross-resistance.
• Evaluated introduction methods for Entomophaga maimaiga, a gypsy moth fungal natural enemy, quantified spread rate, correlated infection prevalence with weather in Michigan.
• Studied interactions of a gypsy moth microsporidium and interactions with the gypsy moth NPV.
• Developed different artificial diets to rear cottonwood leaf beetle, cottonwood borer, and emerald ash borers in the laboratory.

Selected Recent Publication List:

Bauer LS, Pankratz HS. 1993. Nosema scripta n. sp. (Microsporida: Nosematidae), a Microsporidian Parasite of the Cottonwood Leaf Beetle Chrysomela scripta (Coleoptera: Chrysomelidae). Journal of Eukaryotic Microbiology 40:135-141

Smitley DR, Bauer LS, Hajek AE, Sapio FJ, Humber RA. 1995. Introduction and establishment of Entomophaga maimaiga in Michigan. Environmental Entomologist 24:1685-1695

Bauer LS. 1995. Resistance: a threat to the insecticidal crystal proteins of Bacillus thuringiensis.

Hajek AE, Bauer L, McManus ML, Wheeler MM. 1998. Distribution of resting spores of the Lymantria dispar pathogen Entomophaga maimaiga in soil and on bark. BioControl 43:189-200

Bauer LS, Miller DL, Maddox JV, McManus M. 1998. Interactions between nuclear polyhedrosis virus and microsporidia (Protozoa: Microsporida) infecting gypsy moth (Lymantria dispar). Journal of Invertebrate Pathology 72:147-153

Bauer LS. 1999. Gypsy moths get sick too! USDA Forest Service NCRS, Fact Sheet. 2 p http://ncrs.fs.fed.us/pubs/fs/fs_gmbauer99.pdf

Federici BA and Bauer LS. 1998. Cyt1A protein of Bacillus thuringiensis is toxic to the cottonwood leaf beetle, Chrysomela scripta, and suppresses high levels of resistance to Cry3A. Applied and Environmental Microbiology 64:4368-4371

McCullough DG, Bauer LS. 2000. Bt: one option for gypsy moth management. Michigan State University Extension Bulletin E-2724 http://ncrs.fs.fed.us/pubs/eb/eb_msu_e2724.htm

Bauer LS, Vossbrinck C. 2001. A microsporidium from the Asian longhorned beetle in China. In the Proceedings of the Annual Meeting of the Society for Invertebrate Pathology, August 25-30 2001, Noordwijkerhout, Netherlands, p 6

Hajek AE, Wheeler MM, Eastburn CC, Bauer LS. 2001. Storage of resting spores of the gypsy moth fungal pathogen, Entomophaga maimaiga. Biocontrol Science and Technology. 11:637-647

Bauer LS, Miller DL. 2001. The cottonwood borer: a surrogate host for study of the Asian longhorned beetle. In the Proceedings of the Asian Longhorned Borer Research and Development Program Review, November 6-8, 2001, Beltsville, MD, p 61

Loseva O, Ibrahim M, Candas M, Koller CN, Bauer LS, Bulla LA. 2002. Changes in protease activity and Cry3Aa toxin binding in the Colorado potato beetle: implications for insect resistance to Bacillus thuringiensis toxins. Insect Biochemistry and Molecular Biology 32:567-577