Herbicide-resistant weed species

For the Mid-Atlantic and Northeast (alphabetical list)

Certain populations of these weed species have evolved the ability to survive herbicide applications that would normally be lethal in one or more of these states: Connecticut, Delaware, Maryland, Massachusetts, Maine, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia

Species with more than one mode of action (MOA) listed may not be resistant to all listed MOA’s in all states.
Species with more than one mode of action (MOA) listed do not necessarily exhibit multiple resistance.
Compiled from the International Herbicide-Resistant Weed Database and from correspondence with local weed scientists, September 2024.
Follow links to weed profiles that provide key identification characteristics, ecology, management & references from Manage Weeds on Your Farm in most cases.
View resistant species grouped by herbicide mode of action (MOA)

Broadleaf weeds

Common chickweed (Stellaria media)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
States found: DE, MD, PA, VA
Chickweed profile

Common cocklebur (Xanthium strumarium)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
States found: MD
Cocklebur profile

Common groundsel (Senecio vulgaris)

Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
States found: NY
Groundsel profile

Common lambsquarters (Chenopodium album)

Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
States found: CT, DE, MA, MD, ME, NH, NY, PA, RI, VA, VT, WV
Lambsquarters profile

Common ragweed (Ambrosia artemisiifolia)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 5 (Photosystem II inhibitosr e.g. atrazine)
Herbicide group: MOA 9 (Aromatic amino acid inhibitors e.g. glyphosate)
Herbicide group: MOA 14 (Cell membrane disruptors e.g. saflufenacil)
States found: DE, MD, NJ, NY, PA
Ragweed profile

Horseweed (Conyza canadensis)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 9 (Aromatic amino acid inhibitors e.g. glyphosate)
Herbicide group: MOA 22 (Photosystem I electron diverter (e.g. paraquat)
States found: DE, MD, NJ, PA, NY, VA, WV
Horseweed profile

Livid amaranth (Amaranthus blitum)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
States found: NJ
Pigweeds profile
See also: Pigweed identification

Palmer amaranth (Amaranthus palmeri)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
Herbicide group: MOA 9 (Aromatic amino acid inhibitors e.g. glyphosate)
Herbicide group: MOA 14 (Cell membrane disruptors e.g. saflufenacil)
States found: CT, DE, MD, NJ, NY, PA, VA
Pigweeds profile
See also: Pigweed identification

Redroot pigweed (Amaranthus retroflexus)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
Herbicide group: MOA 9 (Aromatic amino acid inhibitors e.g. glyphosate)
States found: CT, DE MD, ME, NH, PA, VA, VT, WV
Pigweeds profile
See also: Pigweed identification

Smooth pigweed (Amaranthus hybridus)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
States found: DE, MD, NJ, NY, PA, VA
Pigweeds profile
See also: Pigweed identification

Thale cress (Arabidopsis thaliana)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
States found: VA

Velvetleaf (Abutilon theophrasti)

Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
States found: MD
Velvetleaf profile

Waterhemp (Amaranthus tuberculatus)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
Herbicide group: MOA 9 (Aromatic amino acid inhibitors e.g. glyphosate)
States found: DE, PA, NY
Waterhemp profile
See also: Pigweed identification

Grass weeds

Annual bluegrass (Poa annua)

Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
States found: VA
Annual bluegrass profile

Barnyard grass (Echinochloa crus-galli)

Herbicide group: MOA 5 (Photosystem II inhibitors e.g. atrazine)
States found: MD
Barnyard grass profile

Giant foxtail (Setaria faberi)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 5 (Photosystem II Inhibitors e.g. atrazine)
States found: MD, PA
Foxtails profile

Goosegrass (Eleusine indica)

Herbicide group: MOA 9 (Aromatic amino acid inhibitors e.g. glyphosate)
Herbicide group: MOA 14 (Cell membrane disruptors e.g. saflufenacil)
States found: NJ, VA
Goosegrass profile

Johnsongrass (Sorghum halepense)

Herbicide group: MOA 1 (Long chain fatty acid inhibitors e.g. clethodim)
Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
States found: VA, WV
Johnsongrass profile

Ryegrass spp. (Lolium spp. )

Herbicide group: MOA 1 (Long chain fatty acid inhibitors e.g. clethodim)
Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
Herbicide group: MOA 9 (Aromatic amino acid inhibitors e.g. glyphosate)
Herbicide group: MOA 27 (HPPD Inhibitors e.g. mesotrione)
States found: DE, MD, NY, PA, VA
Italian ryegrass profile

Shattercane (Sorghum bicolor)

Herbicide group: MOA 2 (ALS inhibitors e.g. nicosulfuron)
States found: PA, VA
Shattercane profile

Smooth crabgrass (Digitaria ischaemum)

Herbicide group: MOA 1 (Long chain fatty acid inhibitors e.g. clethodim)
States found: NJ
Large crabgrass (related species) profile

Yellow foxtail (Setaria pumila)

Herbicide group: MOA 5 (Photosystem II Inhibitors e.g. atrazine)
States found: MD
Foxtail profile

Disclaimer

Disclaimer: Please read the pesticide label prior to use. The information contained at this web site is not a substitute for a pesticide label. Trade names used herein are for convenience only; no endorsement of products is intended, nor is criticism of unnamed products implied. In New York, use the New York State Department of Environmental Conservation’s NYSPAD tool to verify the latest product registration information.