On August 20, 2020, the U.S. Environmental Protection Agency (EPA) announced that it is seeking to add chitosan to the list of active ingredients allowed for in minimum risk pesticides exempted from pesticide registration requirements under Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Section 25(b). A minimum risk product must meet six specific conditions to be exempted from pesticide registration. One of those conditions is that the active ingredient in the minimum risk pesticide be one that is listed specifically by EPA. If added to the list of minimum risk pesticide active ingredients, pesticide products containing chitosan could qualify as minimum risk pesticides provided the other conditions are also satisfied (e.g., using inert ingredients approved by EPA for use in minimum risk pesticides, not making any public health claims).
Chitosan is a naturally occurring polymer that is derived from the shells of crustaceans. It is currently registered as a fungicide, antimicrobial agent, and plant growth regulator that boosts the ability of plants to defend against fungal infections. For uses as a plant growth regulator, chitosan is applied to treat field crops, ornamentals, turf, home gardens, and nurseries. Target pests include early and late blight, downy and powdery mildew, and gray mold. As an antimicrobial agent, chitosan is used on textiles to protection the fabric from bacterial and fungal growth. Chitosan is exempt from the requirement for a pesticide tolerance.
Pesticide Law and Policy blog, 21 August 2020