Weeding with Lasers

New AI-Guided Approach Leaves Vegetables Pesticide-Free

Farmers from the Salinas, California, US, area gather for a laser weeder demonstration on a lettuce crop. ©Carbon Robotics

Imagine a tractor-sized machine that sees the difference between crop and weed, then kills the unwanted plant with a focused beam of light—no herbicide required. That device is already being tested in New Jersey by Rutgers University scientist Thierry Besançon, an associate professor with the Department of Plant Biology in the School of Environmental and Biological Sciences.

According to a Cornell Chronicle study and summary, recent multisite field trials across New Jersey and New York found that deep-learning–guided laser weeders matched or outperformed several common herbicides in vegetable plots (peas, beets, and spinach), cutting final weed biomass by about 97% and increasing crop growth in treated plots. The machines combine high-resolution cameras, artificial intelligence classification, and steerable lasers to target a weed plant’s growing point (meristem) while leaving crops unharmed.

Commercial systems such as Carbon Robotics’ LaserWeeder are already in use on US farms. Adoption considerations include capital cost and speed. Trials show the technology excels on many annual broadleaf weeds when treated at early growth stages (cotyledon to two-leaf)—for example, species such as common lambsquarters (Chenopodium album) and common ragweed (Ambrosia artemisiifolia).

By contrast, the systems are less effective on weeds whose growing point (meristem) is protected below ground (as in many grasses) or on species with a prostrate habit such as common purslane (Portulaca oleracea)—because the laser cannot reliably target the hidden germinating tissue. Additionally, a study on the perennial grass Elymus repens (couch grass) shows that while laser treatment can kill above-ground shoots, root/rhizome regrowth may persist, meaning repeat treatments or combined strategies may be required.

These findings indicate the best fit for the technology is early-emerging broadleaf weeds in row-cropped vegetables and similar settings.

For organic and conventional growers facing rising herbicide resistance and labor constraints, AI-driven laser weeding offers a promising, chemical-free tool—one that Rutgers researchers like Besançon are actively evaluating in real farm conditions to understand performance, limits, and practical costs.

This video is from a camera fixed to the underside of a laser weeder machine and shows weeds being zapped as the machine rolls along the rows. ©Carbon Robotics