The Organic Materials Review Institute has listed RootShield WP from Victor, N.Y.-based BioWorks.
The active ingredient is a patented hybrid fungus, Trichoderma harzianum, strain T-22, that colonizes plant roots, attacking pathogens, according to the company's Web site.
The wettable powder formulation allows application through drip systems and drip irrigation booms used for soil drenches, according to a news release.
The product targets root diseases, including Pythium, Fusarium, Rhizoctonia, Thielaviopsis and Cylindrocladium.
It is registered for use on greenhouse and outdoor ornamentals, herbs and vegetables.