30 September 2026, São Paulo: Brazilian regulators have approved Phytalix, a biological fungicide built on a new class of active ingredient called ascarosides, clearing the way for growers to use it against some of the country’s most damaging soybean and corn diseases. Gainesville, Florida-based Ascribe Bio announced the approval on September 29, calling it the first time any government has registered an ascaroside-based crop protection product.
Phytalix is labeled to control Asian soybean rust, target spot and septoria in soybean, and white spot and southern corn leaf blight in corn. Brazilian authorities also recognized it, based on publicly available registration data, as the first biological product registered in the country specifically against southern corn leaf blight, a fungal disease caused by the pathogen Bipolaris maydis that can spread quickly through corn fields in warm, humid weather and cause significant yield loss if left unchecked.
Ascarosides are small signaling molecules that nematodes, microscopic worms common in soil, naturally produce to communicate with each other, including to trigger defensive responses in the plants they live near. Ascribe Bio, which grew out of natural-products research at the University of Florida, has built its business around isolating and applying these molecules to crops. Rather than attacking a fungus directly the way most chemical fungicides do, Phytalix works by switching on a plant’s own defense pathways before infection takes hold, a mechanism the company likens to a vaccine priming the immune system ahead of exposure to a disease.
A Different Mode of Action
That distinction matters commercially as much as scientifically. Most conventional fungicides work by directly poisoning a fungal pathogen through a specific biochemical pathway, known in the industry as its mode of action. When a single mode of action is used repeatedly, fungal populations can evolve resistance to it, a growing problem in Brazilian soybean and corn systems where diseases like Asian soybean rust have already developed resistance to several major fungicide classes. Because Phytalix works by boosting the plant’s own immune response rather than targeting the pathogen’s biochemistry, Ascribe Bio argues it gives growers a rotation option that does not contribute to the same resistance pressure, and can be layered into existing spray programs rather than replacing them outright.
The company says the product’s performance has been demonstrated across more than 1,000 field trials worldwide, spanning multiple growing regions and seasons, though the underlying trial data has not been published in a peer-reviewed journal and should be read as company-reported results rather than independently verified findings. Ascribe Bio CEO and co-founder Jay Farmer said the approval responds to a specific market need, noting that “Brazilian growers need sustainable disease control options without additional complexity.”
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