Pennsylvania

A cover crop-herbicide interaction trial at Penn State. Photo: Annie Klodd

Penn State Extension Weed Management: http://extension.psu.edu/pests/weeds

Contacts:

Bill Curran, Professor of Weed Science

Annie Klodd, Extension Associate in IWM

Dwight Lingenfelter, Extension Associate in Weed Science

Penn State Integrated Weed Management Research:

  • Reduced Tillage Organic Systems Experiment (ROSE) – weed management in organic field crops while limiting tillage
  • The interaction between cover crops and herbicides in the management of herbicide resistant weeds
  • High Residue Cultivation
  • Herbicide Banding
  • Interseeding cover crops for weed suppression

Map of Palmer amaranth and waterhemp sightings per county in Pennsylvania. Image: Steve Crawford, Penn State.

Herbicide resistant weeds in Pennsylvania

Updated October 21, 2016. Bill Curran, Pennsylvania State University; www.weedscience.org – Pennsylvania

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 – Highest concern

  • Group 9 (glyphosate)
  • Group 2 (ALS)

Waterhemp – Highest concern

  • Group 9 (glyphosate)
  • Group 2 (ALS)

Horseweed – Third highest concern

  • Group 9 (glyphosate)

Lambsquarter

  • Group 5 (atrazine)

Smooth pigweed

  • Group 5 (atrazine)

Redroot pigweed

  • Group 2 (ALS)
  • Group 5 (atrazine)

Shattercane

  • Group 2 (ALS)

Giant foxtail

  • Group 2 (ALS)

Common ragweed

  • Group 9 (glyphosate)

Common chickweed

  • Group 2 (ALS)