Gene-Edited Crops That Glow Could Replace Blanket Field Spraying

A handful of startups are using gene editing to turn crops into their own early-warning systems, programming plants to glow or change color when pests or disease strike — well before any symptom becomes visible to a grower walking the field. As The Wall Street Journal's Yusuf Khan reports, the payoff could be targeted spot treatments instead of blanketing entire fields with fungicides and herbicides, a shift that would cut chemical spend per acre and reshape how growers time applications.

How does the signaling work?

California-based InnerPlant engineers plants at the DNA level so that, in the words of CEO Shely Aronov, "once the plant is reacting to, say, fungal pressure, it's going to start producing a protein that creates an optical signal." The glow is invisible to the human eye. It is readable by camera-equipped tractors, drones or satellites. Deere, which invested in the startup in 2022, has outfitted its smart tractors with cameras to detect the signal, tying the biology directly into machinery already sitting in dealer lots.

The point is detection before loss. Growers typically confirm disease only after visible damage, when yield is already forfeited and rescue treatments cost more per bushel saved.

Who else is building it?

Indiana's Insignum AgTech takes a more colorful route. The company uses gene editing to switch on traits already present in corn's DNA, so leaves turn purple in response to fungal disease and pests. "When you see disease it's too late," says CEO Kyle Mohler, whose farming family once sprayed every acre every year, whether the crop needed it or not. That flat-rate habit is exactly the input cost these firms want to eliminate.

British startup Viridys Bio is working the same problem without editing the plant. It is adapting land-mine sensors to detect the airborne compounds that stressed plants release, betting that hardware sensing can match engineered signals.

What stands in the way?

Most of these technologies remain in testing and need regulatory approval. The European Union bans food with significant genome edits like these. Many U.S. consumers remain wary, and the new cameras or drones the systems require could prove costly for operators already weighing capital budgets.

Alexander Jones, a plant biology professor at the University of Cambridge, says such obstacles make it "tough for these sorts of biology companies to get off the ground and thrive," though he believes "the drawbacks are few and minor and no longer justify the legal and policy roadblocks."

Not everyone is sold on the premise. Praveena Sridhar of the nonprofit Save Soil argues that soil health investments, photonic monitoring and better integrated pest management can deliver similar benefits without modifying crops at all.

The takeaway for now: the sensing traits exist, a major equipment maker has money and cameras in the game, but no commercial acreage carries the signals yet. Regulatory decisions in Washington and Brussels will determine whether these crops reach fields before rival sensor technologies capture the same job.