CONTROL OF SMOOTH CORDGRASS WITH RODEO(R) IN A SOUTHWESTERN WASHINGTON ESTUARY

We investigated efficacy of aerial and ground application of Rodeo(R) to control smooth cordgrass (Spartina alterniflora) on intertidal mudf lats in Willapa Bay, Washington during 1992-1993. The herbicidal formu la was applied to 2 1-ha plots using a helicopter with toe-mounted spr ay boom or by hand-held wand sprayer. Stem densities did not differ fr om pre- to post-treatment between aerially treated and control clones, Stem densities were reduced on clones where the herbicidal formulatio n was applied by hand, Stem density was reduced most at plots located highest in the intertidal zone, Efficacy depended on the time between treatment and subsequent tidal inundation of treated plants.