Michael Flessner

Assistant Professor and Extension Weed Science Specialist

Program Focus

Dr. Flessner’s research program focuses on solving weed management challenges currently facing the Commonwealth, with emphasis placed on sustainable and economic solutions. Herbicide resistant weeds are one such challenge that must be met with strong, proactive approaches to weed management, some of which are outlined below.


Current Projects

Cover Crops for Weed Management

Cover crops are a well-known for their improvements to soil health and quality. However, their utility for weed control has not been fully examined. High-residue cover crops have the potential to suppress winter annual weeds as well as smoother spring germinating annual weeds, thereby reducing the need for herbicide applications. Of particular interest is the use of cover crops for glyphosate resistant horseweed management. Other research efforts include evaluation of cover crops for weediness in subsequent cash crops and herbicide carry-over from the cash crop to the cover crop.


Herbicide Resistant Weed Management

Herbicide resistant weeds are a serious threat to agricultural productivity in Virginia. Both the quantity of weed species with herbicide resistance and the number of herbicides to which resistance occurs has been increasing and is projected to increase. Research efforts to address this challenge include mechanical weed seed destruction at harvest, rotation of herbicide-tolerant seed traits to effectively rotate mechanisms-of-action, cover crops (discussed above), and evaluation of alternative herbicides.


Ph.D.  Crop, Soil and Environmental Sciences, Auburn University, 2014

M.S.   Agronomy and Soils,  Auburn University, 2010

B.S.    Plant Sciences,  University of Tennessee, 2008



2014 - Present    Assistant Professor, Department of Plant Pathology, Physiology, and Weed Science,  Virginia Tech

2010 - 2014       Research Associate II-IV, Agronomy and Soils,  Auburn University

2008 - 2010      Graduate Research Assistant, Agronomy and Soils, Auburn University

2005 - 2008      Research Assistant, Plant Sciences,  University of Tennessee

Program Focus

Dr. Flessner’s Extension program provides statewide leadership in the development and dissemination of weed management best practices for agronomic crops and pasture/forage. Emphasis is placed on current challenges such as management of herbicide-resistant weed species. Dr. Flessner develops publications, web-based media, and presentations in conjunction with Virginia Cooperative Extension, with the mission of empowering stakeholders through nonbiased, research-based information.

 >>>   Follow Dr. Flessner @VTAgWeeds


Current Projects

Virginia Tech Weed ID Clinic 

Dr. Flessner is part of a collaborative team from the Plant Pathology, Physiology, and Weed Science Department and the College of Agriculture who identify and offer control and management recommendations for unknown weed species sent in from throughout Virginia. The Weed ID Clinic has been operating since 1985 and has identified over 8,500 plant samples from every county and independent city in the commonwealth.  Over 1000 unique species have been sent to the clinic in the past decade.


Virginia Tech Weed Identification Website Update

The VT Weeds website (http://oak.ppws.vt.edu/weedindex.htm) was among the first of its kind. Thousands of unique hits are recorded each year from Virginia and beyond. The website has won awards for being an excellent resource for the industry. However, the website is in need of a facelift, which is coming shortly.


Pest Management Guide

Field Crops Chapter (http://pubs.ext.vt.edu/456/456-016/Section_5_Weeds-1.pdf). This resource is freely available for download or is available at your local extension office (http://www.ext.vt.edu/offices/). Dr. Flessner is part of a collaborative team of weed scientists that assemble and annually revise these recommendations. Recommendations are based on herbicide efficacy testing.

Michael Flessner, PhD
  • (540) 231-2910
  • flessner@vt.edu
  • 102A Glade Road Research Facility
    Mail code: 0330
    Blacksburg, VA 24061