Field Crops | Cornell Weed Identification

Field crops are the most common type of agriculture in New York, where corn, soybeans, wheat, barley, triticale, spelt, dry beans, and other field crops are grown. Cornell University is heavily invested in New York’s field crops farmers, supporting many faculty who research field crop breeding, weed and pest research, and resources for farm management. Scroll down for links to problem and common weeds of New York field crops.

Map of CCE Field Crops team service areas, from the field crops field team website.

Field Crops website screenshot from November 2020

Screenshot of CCE Eastern Horticulture herbicide lookup landing page

The statewide CCE Field Crops extension team provides on-the-ground advice and support for farmers around the state.

The Cornell Field Crops website provides timely information on crop management and resources.

Cornell Cooperative Extension’s Eastern Commercial Horticulture has a lookup table for weeds and common herbicides, where you can select your problem weed and see how well common herbicides control that species.

Printable Weed Booklets

These booklets are for printing and taking into the field. They have photos, identification tips, and chemical, mechanical, and cultural management options for the most common and troublesome field crop weeds.

For in-depth species profiles, scroll down to the problem and common weeds of field crops below, and click on the images to reach the species page. For more weeds, look under the “Resources” tab at the top of the page for the site’s full species list.

Image of printable pdf, containing much of the weed ID and management information from this webpage.

Annual Broadleaves

Geometric arrangement of Palmer amaranth leaves.

Palmer amaranth (Amaranthus palmeri)

Waterhemp (Amaranthus tuburculatus)

Horseweed (Conyza canadensis)

Common Ragweed (Ambrosia artemisiifolia)

Common Lambsquarters (Chenopodium album)

Redroot Pigweed (Amaranthus retroflexus)

Wild mustard. Photo by Antonio DiTommaso of Cornell University.

Velvetleaf (Abutilon theophrasti)

Spotted knapweed (Centaurea maculosa)

Wild mustard (Sinapis arvensis)

Perennial Broadleaves

Bull thistle flower with spiny bracts below flower. Photo by John Cardina of Ohio State University, via Bugwood.org.

Mature Horsenettle plant photo by Florida Division of Plant Industry via Florida Department of Agriculture and Consumer Services, Bugwood.org

Bindweeds: field and hedge bindweed

Bull thistle (Cirsium vulgare)

Horsenettle (Solanum carolinense)

Canada thistle (Cirsium arvense)

Additional perennial broadleaves:

Common milkweed (Asclepias syriaca):

Perennial weed that is toxic to livestock, although it is not commonly consumed unless animals are in overgrazed pasture or otherwise short on food resources. Milkweed is also a critical food resource for monarch butterflies, and is becoming scarce in agricultural regions.

Identification information provided by Iowa State University

Management information provided by Washington State University’s Whatman County

Hemp dogbane (Apocynum cannabinum):

Perennial weed that is toxic to livestock.

Identification information provided by Virginia State University: https://www.pubs.ext.vt.edu/450/450-140/450-140.html

Conventional management information provided by the Virginia Cooperative Extension: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/450/450-140/450-140_pdf.pdf

Non-chemical management information provided by Farms.com: https://www.farms.com/field-guide/weed-management/hemp-dogbane.aspx