Curly leaf pondweed is definitely problematic. It emerges in late summer as young sprouts then overwinters on the bottom as short plants. When water warms in spring it rapidly grows toward the surface as it forms prolific winter buds that as the plant dies back, buds fall to the bottom for the late summer re-emergence as new shoots from the buds (turions). The cycle continues. As you mention manual removal is time consuming and hard work. Curly leaf is vulnerable to proper concentrations of a few aquatic herbicides. Slow acting as low dosages contain fluridone such as Sonar and Avast. Also effective as rapid burn down herbicides that contain diquat such as Reward, Harvester, Tsunami and a couple other generic brands. There are granular spot treatment herbicides that kill curlyleaf. Be aware all of the treatments will generally need to be repetitive in successive years because the turions will sprout over the course of the next few years and the chemical treatment usually does not kill every plant in the water body. A few remote curly leaf plants manage to escape by being in some sort of aquatic refuge area. Also reintroduction by natural methods seems to occur especially when the specie is growing in nearby waters.
Edited by Bill Cody (06/10/18 09:01 PM)
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