UV Lights and Laser Weed Zappers Offer Chemical-Free Alternative to Toxic Pesticides

American farms are experimenting successfully with ultraviolet-C light as a form of pest control in place of chemical pesticides, and they’re starting with strawberries. Another company has AI robots that can zap weeds as a suitable replacement for herbicide use, including the widely used glyphosate.

Large tractor robots go out in the dark of night to apply light to strawberry fields, damaging the DNA/RNA of fungi, bacteria, and mites. Many of these pathogens can self-repair during daylight hours, but that ability is disabled in darkness. For that reason, the robots are deployed overnight, and it makes farms more productive at all hours of the day.

UV-C robots from TRIC’s Luna platform can damage pathogens such as powdery mildew and Botrytis, which are common in strawberries. Some models on the platform are also able to vacuum up insects. So far, the experiment has yielded a 70% reduction in pesticide use, and some trials have reported 90% control of certain mites and fungi.

The United States uses over 1 billion pounds of pesticides each year, including herbicides sprayed to control weeds. Herbicides, including Roundup and its primary chemical glyphosate, make up the vast majority of the pesticides used across the country. About 12% of the pesticides used are insecticides, while fungicides are less than 10% of the total pesticide usage.

Trials don’t report any major consistent drops in nutrients like sugar or vitamin C, but there is no long-term study data available on the potential impacts to the crop DNA. In a USDA-funded study from 2020 to 2023, farmers expressed excitement about the technology, but at least one farmer was concerned about potential harm to the soil microbiome, including beneficial microbes and insects. There is little data on this aspect of the UV-C treatment at this time.

A 2015 study on UV-C nighttime treatment of strawberries said the treatment could kill “a significant part of the microbial population on the plant surface,” which the authors described as a “microbial vacuum.” The authors added, “This will result in a

lack of competition from the natural microbial populations to newly arriving airborne conidia of a pathogen, giving it an ecological advantage to colonize the plant. Results from limited studies indicate that after an initial decline, microbial populations recover rather quickly and even increase beyond the original levels, presumably because of the release of nutrients from plant cells.”

The UV-C lights have shown effectiveness in altering the DNA of pathogens that destroy crops and in vacuuming up problematic pests in the fields, but they can’t be used in place of traditional glyphosate-based herbicide sprays to kill weeds in the field. A different company has AI robots that can zap weeds with precision lasers to reduce herbicide use.

Carbon Robotics’ LaserWeeder uses AI-driven cameras and deep-learning models to spot weeds in the dark of night. The cameras can target weeds among common crops and the LaserWeeder zaps them with precision technology. The most recent models can reportedly take out hundreds of thousands of weeds in one hour and do so during the night shift that is otherwise unproductive on farmland.  

There were three trials in New Jersey and New York in 2024 that evaluated the effectiveness of this method. The results showed “laser weeding as effective or superior to S‐metolachlor, bentazon and phenmedipham herbicides applied at label rate in controlling erect annual weeds, including common lambsquarters and common ragweed.” The researchers noted that the laser weeding method was less effective on purslane and annual grasses “because of sequential emergence patterns and protected meristems.”

Braga Fresh, a Salinas Valley California organic baby lettuce farm, purchased two LaserWeeders to cover 4,700 acres at a cost of $1.2 million per machine. On a 5-year depreciation schedule that works out to a cost of $102.13 per acre. The farm had three crews of 25 people to weed the farm by hand before they purchased these LaserWeeders. It would take an average of 90 minutes to complete one acre of weeding at a total cost of $900 per acre. The Director of Farming Kyle Harmon said it was getting more difficult every year to find workers who are willing to do the tedious labor of manual weeding for an organic farm.

While the New York and New Jersey trials had trouble with zapping purslane, Braga Fresh said the LaserWeeder was very effective against purslane and the other common weeds found in the Salinas Valley. Crawling weeds like goosefoot were more difficult to control. The LaserWeeder was initially destroying some of the farm’s arugula crop because of the different look each arugula variety has at different stages in the growth cycle. Within a day and a half, Carbon Robotics updated its model to effectively identify the arugula varieties.

There is no evidence of any harm to beneficial insects or soil microbiomes for farms that have used the LaserWeeder. It provides an alternative to toxic herbicides that do cause ecological harms to the microbiome of the soil along with downstream effects, including residues in drinking water and food.

While the Trump administration offered support to Bayer by filing a Supreme Court brief and signing an executive order to increase domestic production of glyphosate, HHS Secretary Robert F. Kennedy Jr. has supported this emerging technology and the importance of moving away from chemical pesticides.

“We got to get off this stuff, we got to give these farmers an off-ramp so that they can get off it.” Secretary Kennedy said. “There are all these kinds of new exciting technologies that give us a light at the end of the tunnel to transition. And it could be very, very fast. What the president wants to do is accelerate that.”