This program, which is scheduled to continue through October 2006, is part of a comprehensive multi-agency effort to control the infestation of giant salvinia in the Lower Colorado River and associated backwaters. Giant salvinia (Salvinia molesta) is a highly invasive non-native aquatic weed that can damage irrigation systems and waterways. The spray program was implemented to avoid proliferation of the weed downstream.

The pesticides being used for the program include diquat dibromide (Reward), glyphosate [N-(phosphonomethyl) glycine, isopropylamine salt] (Rodeo), and copper carbonate (CuCO3) (Clearigate). According to manufacturer's label, humans and domestic animals should not drink or swim in water treated with diquat or glyphosate for one day after treatment. Copper herbicides have no use restrictions or precautions.

Giant salvinia, described as "the world's worst weed," is an aquatic fern from Brazil which was discovered by biologists in the lower Colorado River in the summer of 1999. The plant is very invasive; under the right conditions, it multiplies rapidly, threatening recreation use of infected waters, fishing areas, irrigation water delivery, hydropower production, endangered species, and sensitive habitats.

The Bureau of Reclamation is leading the effort to control and eradicate this plant from the Colorado River. The Lower Colorado River Giant Salvinia Task Force also includes the Bureau of Land Management, U.S. Fish and Wildlife Service, Arizona Game and Fish Department, California Department of Fish and Game, and other state and local entities; a complete listing can be found on the Task Force's web site at http://lcrsalvinia.org/salviniahome.asp.