Weed topics

Identify the competition

Weed ecology and organic management

Resources on the proper use of chemical management options.

Learn weeds' weaknesses

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

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


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...
  • New York State Integrated Pest Management
Antonio DiTommaso in the Cornell Weed Science Teaching Garden


The classic identification guide “Weeds of the Northeast” sprouted from a collaboration of Cornell researchers. Now, a new edition of the book brings together a pair of uncannily named weed scientists: Antonio DiTommaso and Joseph DiTomaso.

  • New York State Integrated Pest Management
  • School of Integrative Plant Science
  • Horticulture Section


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.