A New Herbicide For Aquatic Invasive Weed Control: HABITAT
Jim Bean, Environmental Resource Specialist, BASF Corporation, 904 Lancelot Lane, Collierville, TN 38017; (901) 853-1444; beanj@basf.com
HABITAT herbicide received full federal registration from the Environmental Protection Agency for use in non-crop aquatic sites in November 2003. HABITAT contains the active ingredient imazapyr that has been registered and used successfully over the past 20 years for weed control in non-crop areas. An experimental use permit (EUP) has allowed BASF to utilize imazapyr in aquatic weed control operations since 1995. Research and EUP data have shown HABITAT herbicide to give excellent control of wetland and emerged aquatic weed species, allowing desirable species to re-colonize the treated area. Data demonstrates that HABITAT provides season-long control of key invasive emergent and shoreline species. Riparian area invasive species have been successfully controlled and the land restored including Purple loosestrife (Lythrum salicaria), phragmites (Phragmites australis), cattail (Typha spp.), water primrose (Ludwigia spp.), sedge species (Cyperus spp.), giant cutgrass (Zizaniopsis miliacea), and giant reed (Arundo donax). Additional emerged species controlled with HABITAT include alligator weed (Alternanthera philoxeroides), water hyacinth (Eichhornia crassipes), parrots feather (Myriophyllum aquaticum), Frog's-bit (Limnobium spongia) and duckweed (Lemna minor and Spirodela polyrhiza).HABITAT is in the imidazolinone family and is the first acetolactate synthase (ALS) inhibitor to be considered as an aquatic herbicide. Imidazolinones exhibit excellent characteristics for aquatic use due to low toxicity and quick break down in water to basic metabolites of carbon, hydrogen, oxygen and nitrogen. Break down occurs through aqueous photolysis and microbial action. HABITAT has low toxicity to mammals, birds, fish and reptiles partially because it acts by inhibiting a biosynthetic process that occurs only in plants. The half-life of HABITAT in water is approximately 7-14 days. Application methods to deliver the herbicide can provide selective control of targeted weed species and flexibility for time-of- application at the site. Imazapyr as the terrestrial product, ARSENAL herbicide, controls numerous terrestrial invasive weeds important to the eastern US including multiflower rose, Japanese knotweed, honeysuckle, cogongrass, Chinese tallow and privet. Low volume foliar applications can result in selective control of these and many other invasive species.