The degradation performance of 11 types of commercially produced degradable starch-polyethylene plastic compost bags was evaluated in municipal yard waste compost sites at Iowa State University (Ames) and in Carroll, Dubuque, and Grinnell, Iowa. Masterbatches for plastic production were provided by Archer Daniels Midland Co. (Decatur, Ill.), St. Lawrence Starch Co. Ltd. (Mississauga, Ontario, C...