This guide focuses on the most problematic weeds in eastern North America for which there are at least some biocontrol agents established and/or available. Multiple photos and descriptions of each weed included in this guide emphasize key identification traits and plant ecology. For each weed included in this guide, all biocontrol agents released or currently found in North America are described individually. Photos highlighting key identification features and damage are included. The release history, current status, and recommended use of each biocontrol agent are described in detail. Recommendations and current impact often vary between the US and Canada, therefore, the information is presented separately. Includes international code of best practices for classical biological control of weeds.