When is the best time to apply aquatic herbicides?

Applying aquatic herbicides in late spring when plants are young and actively growing is considered the best practice for several reasons. At this time, the target aquatic plants are in their early growth stages, which makes them more susceptible to herbicides. This vulnerability can lead to a more effective application, as the herbicides are readily absorbed and translocated throughout the plant, disrupting vital processes necessary for survival.

Additionally, late spring usually coincides with warmer water temperatures, which can enhance the effectiveness of the herbicide. Most aquatic plants are actively growing during this period, making it the optimal time to manage their populations before they can mature and proliferate, potentially causing more significant problems later in the growing season.

In contrast, other options may not yield the same level of effectiveness or may even cause harm to non-target species. For example, applying herbicides in early fall when temperatures drop might be less effective, as plant metabolism slows and growth diminishes, reducing herbicide uptake. Applying in the heat of summer could also lead to rapid plant die-off that may result in oxygen depletion in the water due to rapid decomposition, negatively impacting the ecosystem. Lastly, treating aquatic plants during winter is typically not advisable because many plants are dormant, and fish activity is minimal, reducing the