Virginia

A cover crop weed mgmt trial in Blackstone, VA. Photo: Annie Klodd.

Weed scientists at Virginia Tech conduct a number of studies on herbicide resistant weed management and integrated management practices. They also track herbicide resistant weed populations in the state and provide recommendations for these and other weeds. They also maintain an online weed identification guide.

Virginia Tech Newsletters for Plant Pathology, Physiology, and Weed Science: http://www.ppws.vt.edu/news/newsletters.html

In 2015-16, Virginia Tech conducted surveys throughout the state to track the distribution of three problem weeds: Palmer Amaranth, common ragweed, and marestail. These are shown in the maps below:

Slide2 Virginia county map Palmer 2016Slide3 Slide4

Weed Science Contacts in Virginia:

Michael Flessner – Assistant Professor and Extension Weed Science Specialist

Research in IWM in Virginia

Weed scientists at Virginia Tech manage a wide range of studies on integrated weed management practices. This research is important for learning how different tactics interact to create more effective management programs in the mid-Atlantic region.

Burning wheat windrows in Blackstone, VA. Photo: Annie Klodd

  • Cover crops for weed management and cover crop-herbicide interactions
  • Herbicide resistant weed management
  • Harvest weed seed control (chaff carts and narrow windrow burning)
  • Rotating herbicide-tolerant seed traits to allow rotation of herbicide modes of action
  • Evaluation of herbicide alternatives
  • Palmer amaranth emergence patterns and genetics across the eastern US.

Forming windrows at VA Tech’s HWSC study in Blackstone, VA. Photo: Annie Klodd.

Herbicide resistant weeds in Virginia

Updated Oct. 19, 2016, Source: Michael Flessner, Virginia Tech; www.weedscience.org – Virginia

Reading this list: Each weed with herbicide resistant populations in this state is listed. Underneath each species is a list of the unique resistant biotypes of that weed in the state, according to the herbicide group(s) they are resistant to.

Palmer amaranth

  • Group 2
  • Group 9
  • Groups 2 + 9

Horseweed/marestail

  • Group 2
  • Group 9
  • Groups 2 + 9

Common Ragweed

  • Group 2
  • Group 9
  • Groups 2 + 9

Annual bluegrass

  • Group 5

Chickweed, common

  • Group 2

Italian ryegrass

  • Group 1

Johnsongrass

  • Group 1

Lambsquarters, common

  • Group 5

Redroot pigweed

  • Group 5

Smooth pigweed

  • Group 2
  • Group 5

Shattercane

  • Group 2