The USGS recently made available detailed maps identifying annual usage of 459 pesticides throughout the U.S. The Pesticide National Synthesis Project manages pesticide data from 1992-2009 and provides specific statistics associated with pesticide use per crop and within each county.
The maps were developed for use in national and regional water-quality assessments. The USGS data was collected from surveys of farm operations and USDA statistics on annual harvest-crop acreage. This information was used to calculate use rates for each crop per year.
These maps show interesting information about the nature of pesticide use around the country. Data includes insight into the quantity of pesticide use per U.S. county as well as the specific crop growing in the same area.
The usage maps for all 459 pesticides can be accessed at http://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php.