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Shawn Askew

Shawn Askew
203 PMB, Glade Rd Res Ctr
675 Old Glade Road
Blacksburg, VA 24061


I have a three-way appointment in the School of Plant and Environmental Sciences covering 25% research, 10% teaching and 65% extension.  I develop and extend weed control technologies that minimize impacts to humans and the environment but preserve turfgrass function and aesthetic.  My programmatic accomplishments have fostered new weed management solutions that have been implemented across the U.S. and in parts of East Asia.


  • Weed management in ornamental turfgrass and industrial vegetation
  • Herbicide fate and herbicide physiology


  • Ph.D. Crop Science, North Carolina State University, 2001
  • M.S. Weed Science, Mississippi State University, 1997
  • B.S. Agricultural Pest Management, Mississippi State University, 1995

Program Focus

The research endeavors of my position are closely tied to extension activities. Research efforts of my program include: development and evaluation of new herbicides on site and in the lab/glasshouse, evaluation of organic and cultural weed control, new diagnostic and application technology, and environmental effects of weed management in turfgrass. I also manage the Phytochemistry and Radioactive Materials laboratory at the Glade Road Research Facility where my team conducts research on herbicide physiology.

Current Projects

My lab has generated and spent over $2.0 million in the past decade for research endeavors aimed at improving weed management programs for Virginia turfgrass managers and industrial vegetation specialists.  Most of my grant funding comes from corporate partners, federal grants, the Virginia Turfgrass Foundation, Virginia Golf Course Superintendents Association, and the Virginia Department of Transportation. The following is a synopsis of some projects that are currently underway:

  • Annual bluegrass biotype characterization, hydro-thermal germination response, and control by nonsynthetic treatments as part of a national SCRI grant project.
  • Chemical control of weeds and suppression of weed vegetation or seedheads via herbicide and plant growth regulator treatments.
  • Developing new techniques for weed management during pollinator plant establishment, optimizing bulb lawn performance for pollinator services and aesthetic enhancement, and discovering techniques for lifting and relocating pollinator garden sod.
  • Developing goosegrass control programs in warm-season turfgrass and characterizing successful herbicide mixtures using radio-labeling techniques.
  • Elucidating zoysiagrass response to nonselective and selective herbicides.
  • Exploring epigenetic mechanisms that potentially aid weeds in developing herbicide resistance.

My main contribution to teaching is guest lecturing in offered turf and weeds science courses.  I also mentor graduate students and co-coach the Virginia Tech Weed Science Team. The following summarizes my teaching activities in the past decade:

  • Developed 1 undergraduate course, 1 graduate course, and presented 182 guest lectures in 16 courses offered in 4 departments
  • Mentored 18 undergraduate researchers, graduated 4 M.S. students and 8 Ph.D. students
  • Currently advise 4 Ph.D. students, 1 postdoctoral associate, and 2 undergraduate researchers 

My primary responsibility is to provide statewide leadership in the development of weed control programs for turfgrass and industrial vegetation. Emphasis is placed on development of recommendations and other weed control information pertinent to current problems in home lawns, professional turf (golf courses, football fields, etc.), commercial sod and seed production, and industrial sites (roadways, railways, utility lines, etc.). I maintain a close working relationship with Virginia Cooperative Extension agents and provide training aids and research to address turfgrass weed problems. A significant amount of my time is spent developing extension presentations or publications, troubleshooting client problems, and conversing with stakeholders.

Professor | 2019 - present
Duties: 10% Teaching, 25% Research, 65% Extension
School of Plant and Environmental Sciences
Virginia Polytechnic Institute and State University, Blacksburg, Va. 

Associate Professor | 2018 - 2019
Duties: 10% Teaching, 25% Research, 65% Extension 
School of Plant and Environmental Sciences
Virginia Polytechnic Institute and State University, Blacksburg, Va.

Associate Professor | 2007 - 2018
Duties: 25% Research, 75% Extension (2007 - 2013)
10% Teaching, 25% Research, 65% Extension (2014 - 2018)

Plant Pathology, Physiology, and Weed Science
Virginia Polytechnic Institute and State University, Blacksburg, Va.

Assistant Professor | 2001 - 2007
Duties: 25% Research, 75% Extension
Department of Plant Pathology, Physiology, and Weed Science
Virginia Polytechnic Institute and State University, Blacksburg, Va.

Research Assistant | 1997 - 2001
Crop Science Department
North Carolina State University 

  • R. D. Cake Silver Tray Award, Virginia Turfgrass Council, 2019
  • Outstanding Performance in Pesticide Safety Education, Virginia Department of Agriculture & Consumer Services, 2019
  • President, Northeastern Weed Science Society, 2017
  • Outstanding Extension Award, Weed Science Society of America, 2016 
  • Outstanding Educator, Northeastern Weed Science Society, 2016
  • Outstanding Young Weed Scientist - Academia, Southern Weed Science Society, 2013
  • Outstanding Early Career Weed Scientist, Weed Science Society of America, 2012
  • Allen H. Kates Extension Employee of the Year, Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, 2010 
  • Outstanding Researcher, Northeastern Weed Science Society, 2008 
  1. Rana, S. S.*, and Askew, S. D. 2018 Measuring canopy anomaly influence on golf putt kinematics: Errors associated with simulated putt devices. Crop Sci. 58(2):900-910. doi: 10.2135/cropsci2017.03.0211
  2. Rana, S. S.*, and Askew, S. D. 2018 Measuring canopy anomaly influence on golf putt kinematics: Does annual bluegrass influence ball roll behavior? Crop Sci. 58(2):911-916. doi: 10.2135/cropsci2017.03.0212
  3. Tran, H., Zhu, H., Wu, X., Kim, G., Clarke, C. R., Larose, H., Haak, D. C., Askew, S. D. Barney, J. N., Westwood, J. H. and Zhang, L. 2018. Identification of differentially methylated sites with weak methylation effects. Genes, 9(2):75. doi:10.3390/genes9020075
  4. Askew, S. D. 2017. Plant growth regulators applied in winter improve annual bluegrass (Poa annua) seedhead suppression on golf greens. Weed Technol. 31(5):701-713. doi:10.1017/wet.2017.73
  5. Brewer, J. R.*, Willis, J. B.*, Rana, S. S.*, and Askew, S. D. 2017. Response of six turfgrass species and four weeds to three HPPD-inhibiting herbicides. Agron. J. 109(4):1777-1784. doi:10.2134/agronj2016.06.0345
  6. Cox, M. C.*, Rana, S. S.*, Brewer, J. R.*, and Askew, S. D. 2017. Goosegrass and bermudagrass response to rates and tank mixtures of topramezone and triclopyr. Crop Sci. 57(S1):S310-S321. doi:10.2135/cropsci2016.05.0439
  7. Ervin, E. H., Reams, N., Zhang, X., Boyd, A., and Askew, S. 2017. An integrated nutritional and chemical approach to Poa Annua suppression in creeping bentgrass greens. Crop Sci. 57(2):567-572. doi:10.2135/cropsci2016.05.0308
  8. Goatley, M., Hensler, K., and Askew, S. 2017. Cool-season turfgrass germination and morphological development comparisons at adjusted osmotic potentials. Crop Sci. 57(S1):S201-S208. doi:10.2135/cropsci2016.06.0482
  9. Kim, G., Clarke, C. R., Larose, H., Tran, H. T., Haak, D. C., Zhang, L., Askew, S. D., Barney, J. N., and Westwood, J. H. 2017. Herbicide injury induces DNA methylome alterations in Arabidopsis. PEERJ. 5:e3560. doi:10.7717/peerj.3560
  10. McCall, D. S., Zhang, X., Sullivan, D. G., Askew, S. D., and Ervin, E. H. 2017. Enhanced soil moisture assessment using narrowband reflectance vegetation indices in creeping bentgrass. Crop Sci. 57(S1):S161-S168. doi:10.2135/cropsci2016.06.0471