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United States Department of Agriculture

Agricultural Research Service

Stefan T. Jaronski

Research Entomologist

Stefan Jaronski.Stefan T. Jaronski

Research Entomologist


Phone: 406.433.9486
Fax: 406.433.5038


EducationCurrent ResearchResearch ExperienceRelated Web PagesPublications • SymposiaAbstracts



Additional Pages: Research Projects,* Publications*

*Taken from the Agricultural Research Information System (ARIS) database.




B.S. 1969 Manhattan College, Riverdale NY
M.S. 1972 Cornell University, Ithaca NY
Ph. D. 1978 Cornell University, Ithaca NY




Development of Grasshopper Biocontrol Agents a Lengthy Process 
(PDF; 315KB)   
The Roundup ( By Lois Kerr, June 2010, p. 17-18



NPARL Research Entomologist Stefan Jaronski and Biological Science Technician Julie Grace hosted a Solid Substrate Fermentation Workshop for ARS scientists from related programs Feb. 16 - 18, 2005 at the Sidney ARS facility.  In addition to the workshop, Grace developed a short how-to manual illustrating the techniques discussed during the workshop.  Click here to download The Art of Fermentation. (PDF; 1.39 MB)




My research at Sidney centers on biocontrol of grasshoppers on U.S. rangeland, as well as continuation of older research on management of soil dwelling insect pests of various crops, including sugar beets and corn. My grasshopper work concerns evaluating new technologies and new insect pathogenic fungi for the microbial control of grasshoppers, in close collaboration with USDA APHIS CPHST. This research includes identification of baits, and chemical synergists, as well as new, better fungi and other microorganisms, and taking such technologies from the lab bench to the field.  In the process I have created small scale solid substrate mass production systems based on my industrial experience which not only allows Kg amounts of fungus spores for testing, but also to provide technical advice about such technology worldwide. As a side project I am studying the population genetics of Beauveria bassiana derived from grasshoppers using molecular techniques and comparing the molecular data with other phenotypical charactersitics of the more than 400 Beauveria isolates.  My soil insect-targeted research is directed towards developing a practical mycoinsecticide, based on discovery of Metarhizium microsclerotia, that can be transferred to industry for commercialization for use against soil pest insects (sugarbeet root maggot, cabbage maggot, corn rootworm).  The sugarbeet research is within the larger context of a biologically based management system for both pests and pathogens, using microorganisms, cultural practices, resistant/tolerant hybrids, and induced systemic response.




I joined NPARL in March 2000 as an insect pathologist after a 17-year career in industry. After a Ph.D. program and two postdoctoral appointments concerning microbial control of mosquitoes, I did an abrupt left turn and (a) left the academic community for industry, (b) changed from medical entomology to agricultural pests. From 1983 to 1992, I worked at Abbott Laboratories as an insect pathologist, during which time my research involved commercial development of Beauveria bassiana and Bacillus thuringiensis for use against a wide variety of insects. In 1992 I switched to Mycotech Corp., Butte MT, a small, venture-capital biotech group commercializing Beauveria-based mycoinsecticides. There, I spent 8 years involved in all aspects of commercial development of the fungus – from the early basic research through field trials to generation of registration data, from basic mycology to formulation chemistry, from science to marketing. My last position prior to joining ARS was Manager of Biopesticide Research and Development for Mycotech.




Homing in on Hopper Hordes

Grasshopper Research at NPARL

Grasshoppers: Their Biology, Identification and Management

Microbes for Sugar Beet Maggots (PDF; 24 KB)

Pest Management Research Unit Projects



ARS: NEWS & EVENTS (This link leads to Dr. Jaronski's query within ARS's news and events)




Please note: The most recent publications by this scientist may not yet be listed here. Please check the ARIS "Publications" page for possible new titles.


  • Hoffmann, A.M., French, B.W., Jaronski, S., Gassmann, A.J. 2014. Effects of
    entomopathogens on mortality of western corn rootworm and fitness costs of resistance
    to Cry3Bb1 maize. Journal of Economic Entomology. 107(1):352-360; DOI:10.1603/EC13247.
  • Jaronski, S. 2013. Mycosis inhibits cannibalism by Melanoplus sanguinipes, M.
    differentialis, Schistocerca americana, and Anabrus simplex. Journal of Insect Science.
    13(122):1-9. (PDF)
  • Reddy, G.P., Tangtrakulwanish, K., Wu, S., Miller, J.H., Ophus, V., Prewett, J.,
    Jaronski, S. 2014. Evaluation of the effectiveness of the entomopathogens for the
    management of wireworms (Coleoptera: Elateridae) on spring wheat. Journal of
    Invertebrate Pathology. 120:43–49. DOI 10.1016/j.jip.2014.05.005. (PDF)
  • Bitshadze, N., Jaronski, S., Khasdan, V., Abashidze, E., Abashidze, M., Latchininsky,
    A., Samasdashvili, D., Sokhadze, I., Rippa, M., Ishaaya, I., Horowitz, R. 2013. Joint
    action of Beauveria bassiana and the insect growth regulators diflubenzuron and
    novaluron, on the migratory locust, Locusta migratoria. Journal of Pest Science.
    86(2):293–300. DOI: 10.1007/s10340-012-0476-4. (PDF)
  • Jaronski, S. 2013. Mass production of entomopathogenic fungi: state of the art. In: Morales-Ramos, J.A., Rjoas, M.G, Shaprio-Ilan, D.I., editors. Mass Production of Beneficial Organisms. USA: Academic Press. p. 357-415. (PDF; 2 MB) (Public Domain) 
  • Meikle, W.G., Bon, M., Cook, S.C., Gracia, C.G., Jaronski, S. 2013. Two strains of
    Pseudomonas fluorscens bacteria differentially affect survivorship of waxworm (Galleria
    mellonella) larvae exposed to an arthropod fungal pathogen, Beauveria bassiana.
    Biocontrol Science and Technology. 23(2):220-233.
  • Petzold-Maxwell, J., Jaronski, S., Clifton, E.H., Dunbar, M.W., Jackson, M.A., Gassman,
    A.J. 2013. Interactions among Bt maize, entomopathogens, and rootworm species
    (Coleoptera: Chrysomelidae) in the field: effects on survival, yield and root injury.
    Journal of Economic Entomology. 106(2): 622-632. (PDF)
  • Rudeen, M.L., Jaronski, S., Petzold-Maxwell, J.L., Gassman, A.J. 2013. Entomopathogenic
    fungi in cornfields and their potential to manage larval western corn rootworm
    Diabrotica virgifera virgifera. Journal of Invertebrate Pathology. 114(3):329–332. (PDF)
  • Cossentine, J., Jaronski, S., Thistlewood, H., Yee, W.L. 2011. Impact of Metarhizium brunneum (Hypocreales: Clavicipitaceae) on pre-imaginal Rhagoletis indifferens (Diptera: Tephritidae) within and on the surface of orchard soil. Biocontrol Science and Technology. 21(2):1501-1505. (PDF; 204 KB)
  • Foster, N.R., Jaronski, S., Reuter, K.C., Black, L.R., Schlothauer, R.J., Harper, J.D. 2011. Simulated aerial sprays for field cage evaluation of Beauveria bassiana and Metarhizium brunneum (Ascomycetes: Hypocreales) against Anabrus simplex (Orthoptera: Tettigoniidae) in Montana. Biocontrol Science and Technology. 21(11):1331-1350. (PDF; 619 KB)
  • Cossentine, J., H. Thistlewood, M. Goettel and S.T. Jaronski. 2010. Susceptibility of preimaginal western cherry fruit fly, Rhagoletis indifferens (Diptera: Tephritidae) to Beauveria bassiana (Balsamo) Vuillemin (Deuteromycotina: Hyphomycetes). J. Invertebr. Pathol. 104(2):105-109. (PDF; 153 KB)
  • Dunkel, F.V., S.T. Jaronski, S.U. Meiler, C.W. Sedlak, and K.D. La Veaux-Veo. 2010. Effects of steam-distilled shoot extract of Tagetes minuta (Asterales: Asteraceae) and entomopathogenic fungi on larval Tetanops myopaeformis (Röder). Environ. Entomol. 39(3): 979-988. (PDF; 128 KB
  • Foster, N.R., Jaronski, S., Reuter, C.K., Black, L.R. 2010. Explaining mycoinsecticide activity: poor performance of spray and bait formulations of Beauveria bassiana and Metarhizium brunneum against Mormon cricket in field cage studies. Journal of Orthoptera Research. 19(2):303-313. (PDF; 961 KB)
  • Jackson, M.A., C. Dunlap and S.T. Jaronski. 2010. Ecological considerations in producing and formulating fungal entomopathogens for use in insect biocontrol. In, Ecology of Fungal Entomopathogens. (H.E. Roy, F. E. Vega, D. Chandler, M. Goettel, J.K. Pell, and E. Wajnberg, eds.) Springer, Dordrecht. pp. 129-146. (PDF; 451 KB)
  • Jaronski, S.T. 2010. Ecological Factors in the Inundative Use of Fungal Entomopathogens. BioControl. 55:159–185. (PDF; 760 KB)
  • Searle, K., N. Hobbs, and S. Jaronski. 2010. Asynchrony, fragmentation, and scale determine benefits of landscape heterogeneity to mobile herbivores. Oecologia. 163(3):815-824.  (PDF; 410 KB)
  • Srygley, R.B., and S. Jaronski. 2010. Immune response of Mormon crickets that survived infection by Beauveria bassiana. Psyche. Vol. 2011, 5 pp., Article ID 849038, DOI:10.1155/2011/849038. (PDF; 1218 KB)
  • Wraight, S.P., M.E. Ramos, P.B. Avery, S.T. Jaronski, and J.D. Vandenberg. 2010. Comparative virulence of Beauveria bassiana isolates against Lepidopteran pests of vegetable crops. J. Invertebr. Pathol. 103(3):186-199. (PDF; 239 KB)
  • de Crecy, E., S.T. Jaronski, B. Lyons, T. J. Lyons, and N. O. Keyhani. 2009. Directed evolution of a filamentous fungus to thermotolerance. BMC Biotechnology 2009, 9:74. doi:10.1186/1472-6750-9-74. (PDF; 567 KB)
  • Jackson, M.A. and S.T. Jaronski. 2009. Production of microsclerotia of the fungal entomopathogen Metarhizium anisopliae and their use as a biocontrol agent for soil-inhabiting insects. Mycol. Res., 113(8):842-850. (PDF; 388 KB)
  • Jaronski, S.T. and M.A. Jackson. 2009. Further Progress with Metarhizium microsclerotial production. “Insect Pathogens and Insect Parasitic Nematodes” (R-U Ehlers, N. Crickmore, J. Enkerli, I Glazer, M. Lopez-Ferber and C. Tkaczuk, eds. Bulletin IOBC/wprs 45:275-278.
  • Searle, K.R., N.T. Hobbs and S.T. Jaronski 2009. How does habitat fragmentation influence consumers feeding on pulsed resources? Oecologia 2010, pp.1-10.
  • Turnbow, J. H., K. O’Neill, and S. T. Jaronski. 2009. Thermal biology of the mormon cricket (Anabrus simplex Haldeman [Orthoptera: Tettigoniidae]): I. behavioral thermoregulation. Journal of Insect Science - Submitted and in revision.
  • Jaronski, S. 2008. Australian Metarhizium anisopliae var. Acridum strain FI985 vs. Beauveria bassiana Strain GHA - laboratory efficacy against North American acridids and anabrus simplex. Advances in Applied Acridology.
  • Jaronski, S.T. and M.A. Jackson. 2008. Efficacy of Metarhizium anisopliae microsclerotial granules. Biocont. Sci. Technol. 18(8):849-863. (PDF; 120 KB)
  • Jaronski, S.T. 2007. Soil Ecology of the Entomopathogenic Ascomycetes: A Critical Examination of What We (Think) We Know. In, Use of Entomopathogenic Fungi in Biological Pest Management (K. Maniana and S. Ekesi, eds.) Research SignPosts, Trivandrum India. Pp. 91-144.
  • Jaronski, S.T., C. Fuller-Schaeffer, K. Jung, M. Boetel and A. Majumdar. 2007. Challenges in using Metarhizium anisopliae for biocontrol of Sugarbeet Root Maggot, Tetanops myopaeformis. Working Group “Insect pathogens and Entomopathogenic Nematodes.” J. Enkerli, ed. Bulletin IOBC/wprs. 30(7):119-124. (PDF: 32 KB) (Public Domain)
  • Kabaluk, T., M. Goettel, Jerry Ericsson, M. Erlandson, B. Vernon, S. Jaronski, K. Mackenzie, L. Cosgrove. 2007. Promise versus performance: Working toward the use of Metarhizium anisopliae as a biological control for wireworms. Working Group “Insect pathogens and Entomopathogenic Nematodes.” J. Enkerli, ed. Bulletin IOBC/wprs 30(7): 69-76.
  • Majumdar, A., M. Boetel, and S. T. Jaronski. 2007. Discovery of Fusarium solani as a naturally occurring pathogen of Sugarbeet Root Maggot (Diptera: Ulidiidae) pupae: prevalence and baseline susceptibility. J. Invertebr. Pathol. 97(1):1-8. (PDF; 500 KB)
  • Tharp, C.I., S.L. Blodgett, and S.T. Jaronski. 2007. Control of Wireworms (Elateridae) in Potatoes with Microbial Metarhizium, 2006. Arthropod Management Tests 32:E43. 
  • Campbell, L.G., Boetel, M., Jonason, N.B., Jaronski, S., Smith, L. 2006. Grower-Adoptable Formulations of the Entomopathogenic Fungus Metarhizium anisopliae (Ascomycota: Hypocreales) for Sugarbeet Root Maggot (Diptera: Ulidiidae) Management. Environmental Entomology. 35(4):986-991. (PDF; 93 KB)
  • Majumdar, A., Boetel, M., Jaronski, S., Dregseth, R.J., Schroeder, A.J. 2006. Cereal cover crops and a microbial insecticide for integrated control of sugarbeet root maggot. Sugarbeet Research and Extension Reports. 36:222-227. (PDF: 51 KB)
  • Bruck, D.J., Snelling, J., Dreves, A.J., Jaronski, S. 2005. Laboratory Bioassays of Entomopathogenic Fungi for Control of Delia Radicum (L.) Larvae. Journal of Invertebrate Pathology. 89:179-183. (PDF; 197 KB)
  • Jaronski, S., Campbell Jr, J.E. 2005. Integration of a resistant sugarbeet variety with the insect pathogenic fungus Metarhizium anisopliae to manage the sugarbeet root maggot. Sugarbeet Research and Extension Reports. 36:185-189. (PDF; 54 KB) (Click here to open SBREB Report MS Word document)
  • Jaronski, S.T., Grace, J.A., Schlothauer, R. 2005. Metarhizium anisopliae for biocontrol of sugarbeet root maggot: constraints and challenges. Proceedings, 33rd Biennial Meeting, American Society of Sugar Beet Technologists. pp. 185-187. (PDF; 4017 KB)
  • Leland, J.E., Mcguire, M.R., Grace, J.A., Jaronski, S.T., Ulloa, M., Park, Y.H., and Plattner, R.D. 2005. Strain selection of a fungal entomopathogen, Beauveria bassiana, for control of plant bugs (Lygus spp.) (Heteroptera: Miridae). Biological Control. 35(2):104-114. (PDF; 409 KB)


  • Jaronski, S., Jackson, M.A., Dunlap, C.A., Meikle, W.G. 2010. Novel approaches in formulation of entomopathogenic fungi for control of insects in soil, foliar, and structural habitats: thinking outside the box and expecting the unexpected. In: Proceedings of the 10th International Colloquium on Invertebrate Pathology and Microbial Control. 43th Annual Meeting of the Society for Invertebrate Pathology Conference , July 11-15, 2010, Trabzon, Turkey. 2010 CD-ROM. (PDF; 1003 KB)
  • Jaronski, S. 2007. Mycosis Inhibits Grasshopper Necrophagy. Entomological Society of America Miscellaneous Publications. Paper No. 31456. Available:
  • Jaronski, S., Fuller Schaefer, C.A., Larson, B., Jacobsen, B.J. 2007. Effect of three bacterial disease-control agents on the entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana. Proceedings, 34th Biennial Meeting American Society of Sugarbeet Technologists, February 28-March 3, 2007, Salt Lake City, Utah. p. 206-210. (PDF; 2947 KB)
  • Jaronski, S.T., Grace, J.A., and Schlothauer, R. 2005. Metarhizium anisopliae for Biocontrol of Sugarbeet Root Maggot: Constraints and Challenges. Proceedings, 33rd Biennial Meeting, American Society of Sugar Beet Technologists. p. 185-187.
  • Leland, J.E., Mcguire, M.R., and Jaronski, S. 2005. Field Evaluation of Beauveria bassiana Isolates for Control of Plant Bug (Lygus SPP.). National Cotton Council Beltwide Cotton Conference.    


  • Jackson, M.A., Jaronski, S. 2009. Production of Microsclerotia of Metarhizium anisopliae Using Deep-Tank Liquid Fermentation [abstract]. Society for Invertebrate Pathology Annual Meeting. Abstract No. 114.
  • Wraight, S.P., Jaronski, S., Ramos, M., Griggs, M., Vandenberg, J.D. 2009. Statistical considerations in the analysis of data from replicated bioassays. Meeting Abstract. 42:82.
  • Jackson, M.A., Jaronski, S. 2008. Production of Microsclerotia of the Entomopathogenic Fungus Metarhizium anisopliae in Liquid Culture [abstract]. American Society for Microbiology. Abstract No. O-053.
  • Jackson, M.A., Schisler, D.A., Shearer, J.F., Jaronski, S. 2007. Liquid culture production of fungal microsclerotia for use in biological control [abstract]. XV Congress of European Mycologists, St. Petersburg, Russia. p. 191.  

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