New Species Maps Aim to Reduce Unnecessary Pesticide Limits

Corn growers will soon benefit from more accurate species data that helps guide EPA's new pesticide strategies. The National Corn Growers Association (NCGA) is working with experts to submit new "core maps" to the EPA that show where endangered species are actually found today, not everywhere they've ever been seen.

Why Maps Matter?

Under EPA's framework, Pesticide Use Limitation Areas (PULAs) restrict herbicide, insecticide and eventually fungicide applications near endangered species. Initially, old and outdated maps were used, which didn't account for migration or other population shifts. That meant large portions of farmland were needlessly restricted. By providing updated core maps, those limitations are narrowed to where species are truly present. That way farmers can balance farm productivity with environmental stewardship.

NCGA's First Map: Clubshell Clam

The Clubshell clam is the first of two species maps NCGA is helping refine. It was chosen because of how many states and corn acres are affected, making it a priority for national-level work. Using updated data from GIS and other experts, the new map greatly reduces the acres tied up in restrictions compared to EPA's outdated maps.

According to the EPA's website, across the first 12 species mapped from other organizations, restricted areas have shrunk by nearly 90%. For example, the Poweshiek Skipperling, a small butterfly native to the North Central U.S., was once mapped across 268,000 acres. Updated data revealed its actual range is just 778 acres, dramatically reducing the land under restriction. This gives farmers clearer, science-based guidance for crop protection decisions.

Role for State Associations

While NCGA is focusing nationally on species with broad impacts like the Clubshell clam, there are other endangered species that only affect individual states. Those are best suited for state corn associations to tackle. NCGA encourages affiliates to reach out for guidance and support in working with local agencies on state-specific mapping opportunities.

The Bottom line

Whether it's on the national or the state level, having updated core maps where endangered species are truly located means fewer blanket restrictions, clearer rules and confidence that pesticide limits are grounded in today's science, not outdated maps.

NCGA will release additional information and guidance as core maps are completed and publicly released. In the meantime, state affiliates can reach out to Becky Langer-Curry for a list of endangered species in their area and for additional guidance on current EPA restrictions and core map development.