Tribune is a Syngenta contact and desiccant herbicide containing 37.3 percent diquat dibromide (2 lb diquat cation per gallon, EPA Reg. No. 100-1390). Labeled for aquatic use, it controls submersed, floating, and marginal aquatic weeds including hydrilla, Eurasian watermilfoil, duckweed, and water lettuce. It interferes with photosynthesis in green plant tissue and desiccates the plant on contact. The label rates algae (Spirogyra, Pithophora) as suppression only and directs a tank mix with an approved algaecide for algae control.