Guido Schnabel

Professor of Plant Pathology - Fruit Crops
Graduate Student Coordinator
Plant and Environmental Sciences Department, Public Service Activities

Office: 105 Collings St./220 BRC
Phone: 864-656-6705
Personal Website:


 Educational Background

Univ Stuttgart, Ger 1997

JLU Giessen, Ger 1993

JLU Giessen, Ger 1990

 Courses Taught

Plant Disease Diagnostics Summer Course


Dr. Guido Schnabel is a plant pathologist at Clemson University with over 25 years of experience working with pathogens of fruit crops. He has an active research and extension program focused on management of diseases of small fruits and stone fruits. His lab publishes in highly ranked, peer-reviewed journals. Since 2019 he has been Associate Editor of Pesticide Biochemistry and Physiology'. His research and extension activities were recognized with the APS Lee Hutchins Award for Excellence in Tree Fruit Research in 2011, The APS Excellence in Extension Award in 2015, the Clemson University Godley Snell Award for Excellence in Research and the Clemson University Centennial Professorship Award.

 Research Interests

-integrated management of diseases affecting peach and strawberry
-fungicide resistance identification and management
-molecular mechanisms of fungicide resistance in fungal plant pathogens
-efficacy of fungicides in vitro and in field trials
-prevalence and causes of peach skin disorders

 Extension and Outreach

-provide timely and useful information to commercial growers via production guides, presentations, website, newsletters, smartphone apps, etc
-generate applicable data for sustainable fruit production
-generate new outreach tools such as the MyIPM smartphone app.


Recent Publications
Ishii, H., H. Watanabe, Y. Yamaoka, and G. Schnabel 2022. Sensitivity to fungicides in isolates of Colletotrichum gloeosporioides and C. acutatum species complexes and efficacy against anthranose disease. Pestic. Biochem. Physiol. 182 (2022) 105049.

Herbert, A., C. N. Hancock, B. Cox, G. Schnabel, D. Moreno, R. Carvalho, J. Jones, M. L Paret, X. Geng, H. Wang 2022. Oxytetracycline and streptomycin resistance genes in Xanthomonas arboricola pv. pruni, the causal agent of bacterial spot in peach. Front. Microbiol., 25 February 2022.

Adelberg, J., J. Naylor-Adelberg, S. Miller, K. Gasic, G. Schnabel, P. K. Bryson, C. Saski, S. Parris, and G. Reighard. 2021. In vitro co-culture system for Prunus spp. and A. mellea in phenolic foam rooting matric. In Vitro Cellular &Developmental Biology – Plant. 57:387-397.

Schnabel, G. M. Hu, J. C. Melgar, and G. L. Reighard 2021. Mystery blotches on peach skin – what we know and don’t know about bronzing. Acta Hort. 1304. ISHS 2021. DOI 10.17660/ActaHortic.2021.1304.39.

Schnabel, G., Tan, Q., Schneider, V., and Hideo Ishii 2021. Inherent tolerance of Colletotrichum gloeosporioides to fludioxonil. Pestic. Biochem. Physiol. 172:104767.

Ishii, H., P. K. Bryson, M. Kayamori, T. Miyamoto, Y. Yamaoka, and G. Schnabel 2021. Cross-resistance to the new fungicide mefentrifluconazole in DMI-resistant fungal pathogens. Pestic. Biochem. Physiol. 171:104737.

Wu, Y., C. Saski, G. Schnabel, S. Xiao, and M.J. Hu 2021. A high-quality genome resource of Botrytis fragariae, a new and rapidly spreading fungal pathogen causing strawberry gray mold in the U.S.A." Phytopathology 111:496-499.

Dowling, M., J. Gelain, L. L. May de Mio, and G. Schnabel 2021. Characterization of high fludioxonil resistance in Botrytis cinerea isolates from calibrachoa flowers. Phytopathology 111:478-484.

Boatwright, H. and Schnabel 2020. Evaluation of the intelligent sprayer system in peach production. Plant Dis. 104:3207-3212.

Dowling, M. E. and G. Schnabel 2020. Understanding plant diseases with art and technology. Int. J. Hort. Sci. 20:959-966.

Dowling, M., N. Peres, S. Villani, and G. Schnabel 2020. Managing Colletotrichum on fruit crops; a ‘complex’ challenge. Plant Dis. 104:2301-2316.

Chen, F., G. Schnabel and others 2020. Histone H3 gene is not a suitable marker to distinguish Alternaria tenuissima from A. alternata affecting potato. PlosOne.

Miller, S. B., K. Gasic, G. R. Reighard, W. G. Henderson, P. A. Rollins, M. Vassalos, and G. Schnabel 2020. Preventative root collar excavation reduces peach tree mortality caused by Armillaria root rot on replant sites. Plant Dis. 104:1274-1279.

Munoz, M. G. Schnabel, W. Bridges, and J. E. Faust 2020. Expression of pink pigmentation in rose petals and its relationship with Botrytis cinerea. PHP. 21:152-156.

Chechi, A., Melanie L. Lewis Ivey Rachel R. Kaufman, Karen P. Bryson, and Guido Schnabel 2020. Quinone outside inhibitor-resistant Colletotrichum nymphaeae isolates from strawberry lack mutations in cytb gene. J. Plant Pathol. Doi 10.1007/s42161-020-00565-8.

Bennett, K., Vargo, M., Schnabel, G. (2020). Calcium application method impacts Botrytis blight severity on petunia flowers. HortScience, 55, 192-195.

Bennett, K., Jent, J., Samarakoon, U. C., Schnabel, G., Faust, J. E. (2020). Reduction of Botrytis cinerea infection on petunia flowers following calcium spray applications. HortScience, 55, 188-191.

Lawrence, B., G. Schnabel and J. C. Melgar 2020. Field performance and susceptibility to fungal pathogens of eleven blackberry cultivars. Int J Fruit Sci.

Chen, S., M. Hu, and G. Schnabel 2020. Paralogous CYP51s of Colletotrichum spp. Mediate Differential Sensitivity to Sterol Demethylation Inhibitors. Phytopathology 110:615-625.

Li, Y., S. S. Tsuji, M. Hu, M. P. S. Camara, S. J. Michereff, G. Schnabel, and F. Chen 2019. Characterization of difenoconazole resistance in Lasiodiplodia theobromae from papaya in Brazil. Pest Manag. Sci. 76:1344-1352.

Chen, F., S. S. Tsuji, Y. Li, M. Hu, M. A. Bandeira, M. P. S Camara, S. J. Michereff, G. Schnabel 2020. Reduced sensitivity of azoxystrobin and thiophanate-methyl resistance in Lasiodiplodia theobromae from papaya. Pestic. Biochem. Physiol. 162:60-68.

Cosseboom, S. D., G. Schnabel, and M.J.Hu. 2020. Competitive ability of multifungicide-resistant Botrytis cinerea in a blackberry planting over three years. Pestic. Biochem. Physiol. 163:1-7.


Professional Website
Schnabel lab program video
Schnabel lab smartphone app MyIPM