David M. Geiser, Ph.D.

  • Professor of Mycology
  • Director, Fusarium Research Center
David M. Geiser, Ph.D.
121 Buckhout Lab (office)
118/119 Buckhout Lab (lab)

University Park, PA 16802
Work Phone: 814-865-9773
Fax: 814-863-7217

Areas of Expertise

  • Fusarium and Aspergillus
  • Fungal genetics
  • Fungal systematics and evolution
  • Fungal plant and animal pathogens


  1. B.A., Ecology and Evolutionary Biology, Northwestern University, Evanston, IL, 1987
  2. Ph.D., Genetics, University of Georgia, Athens, GA, 1995
  3. Postdoctoral, University of California, Berkeley, CA, 1998

Areas of Interest

Molecular evolutionary genetics of pathogenic and toxigenic fungi

Program Interests

Research in my lab focuses on the molecular evolutionary genetics of fungi, mostly in the realm of molecular phylogenetics and systematics at the species level. We apply these tools mostly to identify and better understand the fungal culprits in plant and animal diseases and toxicoses. Unfortunately, identifying fungi using traditional micromorphological tools is very difficult, and tends to lead to species concepts that are too broad. We use the tools of multilocus molecular phylogenetics to recognize and identify species, which provides a much more objective and reliable framework for understanding the biology of these fungi.

As Director of the Fusarium Research Center at Penn State, I also curate the world's largest collection of cultures of Fusarium, one of the most important genera of toxigenic and pathogenic fungi. We are nearing 20,000 accessions and provide isolates to certified researchers, and also provide identification and other services. Most of the research in my lab naturally involves this important genus, but I am also involved in projects in a variety of other fungi.

Recent Publications:

Aoki T, Kasson M, Berger M, Freeman S, Geiser D, O'Donnell K. 2018. Fusarium oligoseptatum sp. nov., a mycosymbiont of the ambrosia beetle Euwallacea validus in the Eastern US and typification of F. ambrosium. Fungal Systematics and Evolution 1:23-39.

Jacobs-Venter A, Laraba I, Geiser DM, Busman M, Vaughan MM, Proctor RH, McCormick SP, O’Donnell K. 2018. Molecular systematics of two sister clades, the Fusarium concolor and F. babinda species complexes, and the discovery of a novel microcycle macroconidium–producing species from South Africa. Mycologia:1-16.

O’Donnell K, McCormick SP, Busman M, Proctor RH, Ward TJ, Doehring G, Geiser DM, Alberts JF, Rheeder JP. 2018. Marasas et al. 1984 “Toxigenic Fusarium Species: Identity and Mycotoxicology” revisited. Mycologia:1-23.

Wickert KL, Metheny AM, Davis D, Geiser D, Wenzel JW, Planinsek D, Kasson MT. 2018. First report of Fusarium stem canker on Pyrularia pubera, a rare native parasitic shrub in forests of southwestern Pennsylvania. Plant disease.

Laraba, I., Botreghda, H., Abdallah, N., Bouaicha, O., Obanor, F., Moretti, A., Geiser, D. M., Kim, H.-S., McCormick, S. P., Proctor, R. H., Kelly, A. C., Ward, T. J., & O'Donnell, K. (2017). Population genetic structure and mycotoxin potential of the wheat crown rot and head blight pathogen Fusarium culmorum in Algeria. , 103, 34-41. 

McCluskey, K., K.B. Barker, H.A. Barton, K. Boundy-Mills, D.R. Brown, J.A. Coddington, K. Cook, P. Desmeth, D. Geiser, J.A. Glaeser, S. Greene, S. Kang, M.W. Lomas, U. Melcher, S.E. Miller, D.R. Nobles, Jr., K.J. Owens, J.H. Reichman, M. da Silva, J. Wertz, C. Whitworth, D. Smith. 2017. The U.S. Culture Collection Network Responding to the Requirements of the Nagoya Protocol on Access and Benefit Sharing. MBio 8.

Hibbett, D., K. Abarenkov, U. Koljalg, M. Opik, B. Chai, J.R. Cole, Q. Wang, P.W. Crous, V.A. Robert, T. Helgason, J. Herr, P. Kirk, S. Lueschow, K. O’Donnell, H. Nilsson, R. Oono, C.L. Schoch, C. Smyth, D. Walker, A. Porras-Alfaro, J.W. Taylor, D.M. Geiser. 2016. Sequence-based classification and identification of Fungi. Mycologia, doi:10.3852/16-130

Ren R, Sun YZ, Zhao Y, Geiser D, Ma H, Zhou X. 2016. Phylogenetic resolution of deep eukaryotic and fungal relationships using conserved low-copy nuclear genes. Genome Biol Evol 9: 2683-2701.

McCluskey K, Alvarez A, Bennett R, Bokati D, Boundy-Mills K, Brown D, Bull C, Coffey M, Dreaden T, Duke C, Dye G, Ehmke E, Eversole K, Fenstermacher K, Geiser D, Glaeser J, Green S, Gribble L, Griffith LP, Hanser K, Humber R, Johnson BW, Kermode A, Krichevsky M, Laudon M, Leach J, Leslie J, May M, Melcher U, Nobles D, Fonseca NR, Robinson S, Ryan M, Scott J, Silflow C, Vidaver A, Webb KM, Wertz JE, Yentsch S, and Zehr S. 2016. The U.S. Culture Collection Network lays the foundation for progress in preservation of valuable microbial resources. Phytopathology 106: 532-540.

O’Donnell, K, Sutton, DA, Wiederhold, N, Robert, VARG, Crous, PW, Geiser DM. 2016. Veterinary fusarioses within the United States. J. Clin. Microbiol. 54: 2813-2819.

O’Donnell, K, Libeskind-Hadas, R, Hulcr, J, Bateman, C, Kasson, MT, Ploetz, RC, Konkol, JL, Ploetz, JN, Carillo, D, Campbell, A, Duncan, RE, Liyanage, PNH, Eskalen, A, Lynch, SC, Geiser, DM, Freeman, S, Mendel, Z, Sharon, M, Aoki, T, Cosse, AA, Rooney, AP. 2016. Invasive Asian Fusarium-Euwallacea ambrosia beetle mutualists pose a serious threat to forests, urban landscapes and the avocado industry. Phytoparasitica 44: 435-442.

Herr JR, Scully ED, Geib SM, Hoover K, Carlson JE, Geiser DM. 2016 Genome sequence of Fusarium isolate MYA-4552 from the midgut of Anoplophora glabripennis, an invasive, wood-boring beetle. Genome Announcements 4: e00544-16.

Shroers H-J, Samuels GJ, Zhang N, Short DPG, Juba JH, Geiser DM. 2016. Epitypification of Fusisporium (Fusarium) solani and its assignment to a common phylogenetic species in the Fusarium solani Species Complex. Mycologia doi 10.3852/15-255.

O’Donnell K, Ward TJ, Robert VARG, Crous PW, Geiser DM, Kang S. 2015. DNA sequence-based identification of Fusarium: Current status and future directions. Phytoparasitica 43: 583-595.

O’Donnell K, Sink S, Libeskind-Hadas R, Hulcr J, Kasson MT, Ploetz RC, Konkol JL, Ploetz JN, Carrillo D, Campbell A, Duncan RE, Liyanage PNH, Eskalen A, Na F, Geiser DM, Bateman C, Freeman S, Mendel Z, Sharon M, Aoki T, Cossé AA, Rooney AP. 2015 Discordant phylogenies suggest repeated host shifts in the Fusarium-Euwallacea ambrosia beetle mutualism. Fungal Genetics and Biology 82: 277-290.

Araújo JPM, Evans HC, Geiser DM, Mackay WP, Hughes DP. 2015. Uravelling the diversity behind the Ophiocordyceps unliateralis (Ophiocordycipitaceae) complex: Three new species of zombie-ant fungi from the Brazilian Amazon. Phytotaxa 220: 224-238.

Geiser DM. 2015. Antifungal design: The toxicity-resistance yin-yang. (invited News and Views) Nature Chemical Biology 11: 453-454.

Montecchio M, Faccoli M, Short DPG, Fanchin M, Geiser DM, Kasson MT. 2015. First report of Fusarium solani phylogenetic species 25 associated with early stages of Thousand Cankers Disease on Juglans nigra  and Juglans regia in Italy.  Plant Disease 99: 1183.

Guo L, Blatt AZ, Geiser DM, Jiménez-Gasco MM, Kuldau GA. 2015. Mating type and spore killing characterization of Fusarium verticillioides strains.  Mycological Progress 14: 1-6.

De Hoog CS, Chaturvedi V, Denning DW, Dyer PS, Frisvad JC, Geiser DM, Gräser Y, Guarro J, Haase G, Kwon-Chung KJ, Meis JF, Meyer W, Pitt JI, Samson RA, Taylor JW, Tintelnot K, Vitale RG, Walsh TJ, Lackner M. 2015. Name changes in medically important fungi and the implications for clinical practice. J. Clin. Microbiol.  53: 1056-1062.

Elmore MH, McGary KL, Wisecaver JH, Slot JC, Geiser DM, Sink S, O’Donnell K, Rojas A. 2015. Clustering of two genes putatively involved in cyanate detoxification evolved recently and independently in multiple fungal lineages. Genome Biology and Evolution 7: 789-800.

Aoki T, Vaughan MM, McCormick SP, Busman M, Ward TJ, Kelly A, O’Donnell K, Geiser DM. 2015. Fusarium dactydilis sp. nov., a novel nivalenol toxin-producing species sister to F. pseudograminearum isolated from orchard grass (Dactylis glomerata) in Oregon and New Zealand. Mycologia 107: 409-418.

Geiser DM, LoBuglio KF, Gueidan C. 2015. Pezizomycotina: Eurotiomycetes. Pp 121-141 in The Mycota VII, Systematics and Evolution, Part B. Second Edition. McLaughlin DJ, Spatafora JW, Lemke PA, eds. Springer, Berlin Heidelberg.

Aoki T, O’Donnell K, Geiser DM. 2014. Systematics of key phytopathogenic Fusarium species: current status and future challenges.  J. Gen. Plant Path. 80: 189-201.

Short DPG, O’Donnell K, Geiser DM. 2014. Clonality, recombination, and hybridization in the plumbing-inhabiting human pathogen Fusarium keratoplasticum inferred from multilocus sequence typing. BMC Evolutionary Biology 14:91.

Park B, Martin F, Geiser DM, Kim HS, Mansfield MA, Nikolaeva E, Park SY, Coffey MD, Russo J, Kim SH, Balci Y, Agad G, Burgess T, Grunwald NJ, Cheong K, Choi J, Lee YH, Kang S. 2013. Phytophthora Database 2.0: Update and Future Direction.  Phytopathology 103: 1204-1208.

Ma L, Geiser DM, Proctor RH, Rooney AP, O'Donnell K, Trail F, Gardiner DM, Manners JM, Kazan K. 2013. Fusarium Pathogenomics. Annu. Rev. Microbiol. 67: 399-416.

Kasson MP, O'Donnell K, Rooney AP, Sink S, Ploetz RC, Ploetz JN, Konkol JL, Carrillo D, Freeman S, Mendel Z, Smith JA, Black AW, Hulcr J, Bateman C, Stefkova K, Campbell PR, Geering ADW, Dann EK, Esklalen A, Mohotti K, Short DPG, Aoki T, Fenstermacher KA, Davis DD, Geiser DM. 2013. An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by ambrosia beetles in the genus Euwallacea on avocado and other plant hosts. Fungal Genetics and Biology. 56: 147-157.

Short DPG, O'Donnell K, Thrane U, Fog Nielsen K, Zhang N, Juba JH, Geiser DM. 2013. Phylogenetic relationships among members of the Fusarium solani species complex in human infections, and the descriptions of F. keratoplasticum sp. nov. and F. petroliphilum stat. nov. Fungal Genetics and Biology, 53: 59-70.

Aoki T, Smith JA, Mount LL, Geiser DM, O'Donnell K. 2013. Fusarium torreyae sp. nov., a pathogen causing canker disease of Florida torreya (Torreya taxifolia), a critically endangered conifer restricted to northern Florida and southwestern Georgia. Mycologia, 105: 312-319.

Geiser DM, Aoki T, Bacon CW, Baker SE, Bhattacharayya MB, Brandt M, Burgess LW, Chulze S, Coleman JJ, Correll JC, Covert SF, Crous PW, Cuomo CA, de Hoog GS, Di Pietro A, Elmer WH, Epstein L, Frandsen RJN, Freeman S, Gagkaeva T, Glenn AE, Gordon TR, Gregory NF, Hammond-Kosack KE, Hanson LE, Jimenez Gasco MM, Kang S, Kistler HC, Kuldau GA, Leslie JF, Logrieco A, Lu G, Lysøe E, Ma L, McCormick SP, Migheli Q, Moretti A, Munaut F, O'Donnell K, Pfenning LH, Ploetz RC, Proctor RH, Rehner SA, Robert VARG, Rooney AP, Salleh B, Scandiani MM, Scauflaire J, Short DPG, Steenkamp ET, Suga H, Summerell BA, Sutton DA, Thrane U, Trail F, van Diepeningen A, VanEtten HD, Viljoen A, Waalwijk C, Ward TJ, Wingfield MJ, Xu J, Yang X, Yli-Mattila T, Zhang N. 2013. LETTER TO THE EDITOR: One Fungus, One Name: Defining the genus Fusarium in a scientifically robust way that preserves longstanding use. Phytopathology, 103: 400-408.

O'Donnell K, Rooney AP, Proctor RH, Brown DW, McCormick SP, Ward TJ, Frandsen RJN, Lysøe E, Rehner SA, Aoki T, Robert VARG, Crous PW, Groenewald JZ, Kang S, Geiser DM. 2013. Phylogenetic analyses of RPB1 and RPB2 support a middle Cretaceous origin for a clade comprising all agriculturally and medically important fusaria. Fungal Genetics and Biology, 52: 20-31.

Rossman AY, Seifert KA, Samuels GJ, Minnis AM, Schroers H-J, Lombard L, Crous PW, Põldmaa K, Cannon PF, Summerbell RC, Geiser DM, Zhuang W, Hirooka Y, Herrera C, Salgado-Salazar C, Chaverri P. 2013. Genera in Bionectriaceae, Hypocreaceae, and Nectriaceae (Hypocreales) proposed for acceptance or rejection. IMA Fungus 4: 41-51.