interrow weeder

Weed Science

Weed identification and management resources to help you reduce the impact of these unwanted plants in fields, gardens, landscapes and ecosystems.

Weed topics

Weed identification

Identify the competition

Ecological management

Weed ecology and organic management

Herbicides

Resources on the proper use of chemical management options.

Weed profiles

Learn weeds' weaknesses

About our programs

Weed science labs and programs at Cornell

New and improved!

2nd edition of Weeds of the Northeast now available

This fully updated second edition of the best-selling Weeds of the Northeast provides lavish illustrations for ready identification of more than 500 common and economically important weeds in the Northeast and in the Upper Midwest and Mid-Atlantic states. 

This new edition covers the region south to North Carolina, north to Maine and southern Canada, and west to Wisconsin. This practical guide includes descriptions and photos of floral and vegetative characteristics, giving anyone who works with plants the ability to identify weeds before they flower.

Don't miss 'Chats in the Stacks' with author Toni DiTommaso April 20, 2023 at 4 p.m. in Mann Library 160 and via Zoom. View event.

weeds of the northeeast cover

Weed science news

Close up of a patch of waterhemp

News

Superweed in NYS found resistant to widely used herbicide

New research confirms glyphosate-resistant waterhemp for the first time in New York state, with significant consequences for soybean growers, many of whom use the herbicide as their primary method of weed control.

  • Cornell AgriTech
  • School of Integrative Plant Science
  • Soil and Crop Sciences Section
weed graphic

Field Note

Ask the Expert: What’s Up with Weeds?

  • School of Integrative Plant Science
  • Soil and Crop Sciences Section
a stump with the words "Into the Weeds" written on it

News

Into the Weeds podcast looks at hazards versus risks of glyphosate
There is much confusion about the potential for glyphosate (the active ingredient in the herbicide Roundup®) to cause adverse health effects, including cancer.—Dan Wixted Dan Wixted of NYSIPM’s Pesticide Safety Education Program (PSEP) joined...
  • Cornell Integrated Pest Management

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.