Steven Jeffers

Professor of Plant Pathology & Extension Specialist, Ornamental Crops & Trees
Horticulture Program Team, Plant and Environmental Sciences Department

Office: 214 Biosystems Research Complex (BRC)
Phone: 864-656-7157

Email: sjffrs@clemson.edu

Educational Background

Ph.D. Plant Pathology
Cornell University 1985

M.S. Plant Pathology
Cornell University 1980

B.S. Plant Science
University of California, Davis 1976

Courses Taught

PLPA 3100/3101 Principles of Plant Pathology, for undergraduate students: Fall
PLPA 8020 Principles of Plant Pathology, for graduate students: Fall
PLPA 4110/6110 Plant Disease Diagnosis (one unit): Summers of odd years
PLPA 3020 Plant Pathology Research, for undergrad students: Fall & Spring as needed

Profile

I am a Professor and Extension Specialist with statewide responsibilities for diseases of ornamental crops in nurseries, greenhouses, and landscapes, and I also work on diseases of trees in both urban and natural ecosystems. I collaborate with the SC Dept. of Plant Industry, USDA-APHIS, and the USDA Forest Service to keep Phytophthora ramorum out of the Southeastern US and with The American Chestnut Foundation to screen hybrid chestnut seedlings for resistance to Phytophthora cinnamomi. I came to Clemson University in 1995 after 7 years at the University of Wisconsin-Madison working on fruit crop diseases and 3 years in private industry developing biological control products for postharvest diseases.

Research Interests

Currently, my research focuses on diseases caused by species of Phytophthora and rust diseases. I am interested in the biology and ecology of Phytophthora spp., pathogen detection, identifying sources of inoculum, and integrated disease management, including optimizing fungicide applications, manipulating cultural practices, evaluating host plant resistance, and investigating the feasibility of biological control options.

Extension and Outreach

The overall objective of my extension program is to assist growers and plant maintenance professionals in South Carolina in making disease management decisions that are effective, economical, and safe. This is accomplished by (1) teaching early recognition and accurate diagnosis of ornamental crop diseases; (2) investigating the etiology, epidemiology, and management of these diseases; and (3) introducing and implementing integrated disease management programs.

Publications

Ridge, G. A., Bell, N. L., Gitto, A. J., Jeffers, S. N., and White, S. A. 2019. Phytophthora species associated with plants in constructed wetlands and vegetated channels at a commercial ornamental plant nursery over time. HortTechnology 29:736-744.

Zhebentyayeva, T. N., Sisco, P. H., Georgi, L. L., Jeffers, S. N., Perkins, M. T., James, J. B., Hebard, F. B., Saski, C., Nelson, C. D., and Abbott, A. G. 2019. Dissecting resistance to Phytophthora cinnamomi in interspecific hybrid chestnut crosses using sequence-based genotyping and QTL mapping. Phytopathology 109:1594-1604.

Westbrook, J. W., James, J. B., Sisco, P. H., Frampton, J., Lucas, S., and Jeffers, S. N. 2019. Resistance to Phytophthora cinnamomi in American chestnut (Castanea dentata) backcross populations that descended from two Chinese chestnut (Castanea mollissima) sources of resistance. Plant Disease 103:1631-1641.

Gitto, A. J., Jeffers, S. N., Graney, L. S., Loyd, A. L., and Bechtel, C. N. 2018. First report of Phytophthora occultans causing root rot on American boxwood planted in residential landscapes in the eastern United States. Plant Disease 102:2384.

Drechsler, D. T., Jeffers, S. N., and Bridges, W. C. 2014. Phytophthora nicotianae can cause both crown rot and foliage blight on Phlox paniculata in South Carolina. Online. Plant Health Progress doi:10.1094/PHP-14-0020. [PHP 15:159-165]

Ridge, G. A., Jeffers, S. N., Bridges, W. C., Jr., and White, S. A. 2014. In situ production of zoospores by five species of Phytophthora in aqueous environments for use as inocula. Plant Disease 98:551-558.

Nyberg, E. T., Jeffers, S. N., Bridges, W. C., and White, S. A. 2014. Removal of plant pathogen propagules from irrigation runoff using slow filtration systems: Quantifying physical and biological components. Water, Air, & Soil Pollution 225:1999. 11 pp.

Benson, D. M., and S. N. Jeffers. 2014. Phytophthora root rot. Pages 5-10 in: Compendium of Rhododendron and Azalea Diseases and Pests, Second Edition. R. G. Linderman and D. M. Benson, eds. American Phytopathological Society, St. Paul, MN.

Zhebentyayeva, T., Chandra , A., Abbott, A.G., Staton, M.E., Olukolu, B.A., Hebard , F.V., Georgi, L.L., Jeffers, S.N., Sisco, P.H., James , J.B. and Nelson, C.D. 2014. Genetic and genomic resources for mapping resistance to Phytophthora cinnamomi in chestnut. Acta Horticulturae (ISHS) 1019:263-270.

Valencia-Boti­n, A. J., Jeffers, S. N., Palmer, C. L., and Buck, J. W. 2013. Fungicides used alone, in combinations, and in rotations for managing gladiolus rust in Mexico. Plant Dis. 97:1491-1496

Dong, W., Jeffers, S. N., and Buck, J. W. 2013. Management of daylily rust with different fungicides and application methods. Plant Dis. 97:921-926.

Scocco, E. A., Walcott, R. R., Jeffers, S. N., and Buck, J.W. 2013. Detection of Puccinia pelargonii-zonalis-infected geranium tissues and urediniospores. J. Phytopathology 161:341–347.

Olson, H. A., Jeffers, S. N., Ivors, K. L., Steddom, K. C., Williams-Woodward, J. L., Mmbaga, M. T., Benson, D. M., and Hong, C. X. 2013. Diversity and mefenoxam sensitivity of Phytophthora spp. associated with the ornamental horticulture industry in the southeastern US. Plant Disease 97:86-92.

Meadows, I. M., Hwang, J., and Jeffers, S. N. 2013. Eliminating Phytophthora spp. from stream water throughout the year with algaecides. Pages 48-50 in: Proceedings of the Sudden Oak Death Fifth Science Symposium. Frankel, S. J., Kliejunas, J. T., Palmieri, K. M., and Alexander, J. M., tech. coords. Gen. Tech. Rep. PSW-GTR-243. US Dept. of Agric., Forest Service, Pacific Southwest Research Station. Albany, CA.

Oak, S. A., Hwang, J., and Jeffers, S. N. 2013. Comparison of in situ and in vitro baiting assays for Phytophthora ramorum survey of waterways in the southeastern USA. Pages 51-52 in: Proceedings of the Sudden Oak Death Fifth Science Symposium. Frankel, S. J., Kliejunas, J. T., Palmieri, K. M., and Alexander, J. M., tech. coords. Gen. Tech. Rep. PSW-GTR-243. US Dept. of Agric., Forest Service, Pacific Southwest Research Station. Albany, CA.