Lets first talk about timing. The timing in which Phragmites is treated with Rodeo coincides with the time of year that they have fully developed their seed heads. The reason for this is because the plant has invested a lot of energy reserves from the stolons to make those seeds. Thus you hit it when it is at its weakest. That normally coincides with early September, +/-. Amphibian larvae have left the building, so to say, by that time. Shellfish larvae should also not be an issue at that time, but I'm not a shellfish expert. Rodeo is considered an 'aquatic approved' herbicide. The most important aspects are that the herbicide should wet the plant, but not to the point of dripping, and that a NON-IONIC surfactanct be used in conjunction with the Rodeo. Rodeo is a glyphosate based herbicide, which means that it is non-selective and will kill anything, as opposed to triclopyr which only kills broad-leafed plants and not grasses. Sometimes another herbicide, called Habitat, is added to the Rodeo to make it even more effective.
Other options include hand swiping, which is using a special glove to get the herbicide on the plant directly and not through the air. You can do a cut-stem treatment where you cut it near the base and then 'pour' a little juice into the stem. You can do 'wicking,' where you wipe the tops of the plants with a canvas-covered applicator. The drawbacks include not being as effective and certainly will cost much more than aerial spraying.
Brandon B. Faneuf, Principal PWS, RPSS, CPESC, CWB
Ecosystem Solutions, Inc.