Dr. James Leary, CTAHR Invasive Weed Specialist, conducts new field trials on windy Waimea ranchland, Hawaii Island, targeting fireweed (Senecio madagascariensis). He demonstrates a modified spray system for high wind conditions. Herbicides tested were: 2,4-D® (active ingredient: 2,4-Dichlorophenol), Cimarron® Plus (active ingredient: metsulfuron methyl and chlorsulfuron), and Milestone® VM (active ingredient: aminopyralid). Preliminary results are shown 30 days later. Partial funding provided by the USDA via the RREA and TSTAR programs. Technical coordination also provided by USDA-NRCS.