Dicamba Herbicide Updates
Dicamba containing herbicides have been in the news and under review by state and federal pesticide regulators since 2017, based on excessively high numbers of off-target movement (drift and volatilization) complaints.
This website is intended to provide interested parties with regulatory and other related information associated with dicamba herbicides in Indiana. Additional resources will be provided as they are available.
Dicamba Use in Indiana:
Certain formulations of Dicamba are classified as restricted use pesticides (RUP) in Indiana. According to IC 15-16-4-37, any pesticide product containing dicamba concentrations greater than or equal to 6.5% and are labeled for agricultural uses. The RUP classification does not apply to products labeled solely for use on turf or nonagricultural (i.e. lawn and landscape) use sites.
Sale, distribution, and use of a state RUP follows the same regulations as a federal RUP. Additional information on RUPs can be found on our RUP Dealer page.
Dicamba products that are classified as state RUPs also have a Highly Volatile Herbicide (HVH) Determination in the state of Indiana. According to IC 15-16-4-17, an HVH is a herbicide that the Indiana Pesticide Review Board (IPRB) has determined to be capable of emitting vapors that may cause serious injury to non-target plants through the movement of these vapors from the application site. Through the HVH determination, the IPRB established requirements to significantly reduce the incidence of off-target movement of dicamba to protect sensitive non-target plants. Requirements include:
- Prohibit the sale or distribution of dicamba HVHs to end users, except with written permission provided by OISC.
- Prohibit the application of dicamba HVHs, except with written permission provided by OISC.
- Require the use of volatility reduction adjuvants (VRA) in each application tank mix that contains a dicamba HVH.
- VRAs are not required during October 1st through March 1st.
OISC has implemented the written permission requirement through a general permitting process. OISC will not be issuing individual written notices of permission or individual permits. Instead, a General Permit has been issued by OISC to cover all HVH sale and distribution and HVH use. Therefore:
- All Restricted Use Pesticide (RUP) dealers registered and permitted by OISC are automatically covered by the General Permit for Sale or Distribution and are eligible to sell or distribute the HVHs.
- All certified and licensed Category 1 (agricultural) commercial applicators and all certified and licensed private applicators (farmers) are automatically covered by the General Permit for Application and are eligible to use the HVHs according to label directions.
As with all pesticide use, applicators must follow all directions and restrictions also identified on the product label.
Indiana Resources:
- Dicamba RUP and HVH Frequently Asked Questions (04/09/25)
- Indiana Restricted Use Pesticides (RUP) Listing (04/2025)
The U.S. Environmental Protection Agency (EPA) has a collection of resources available for dicamba:
- Registration of Dicamba for Use on Dicamba-Tolerant Crops
- Revised Dicamba Notice & Existing Stocks Order
- Formerly-Registered Dicamba Products - Frequently Asked Questions
- Dicamba Training Requirements — Frequently Asked Questions
Other Additional Resources: