Aquatic Pest Control
What this category covers
Aquatic applicators control algae, submerged and floating weeds, and emergent vegetation in ponds, lakes, canals, and irrigation systems. The defining feature of this category is that the treated water is usually also used for something else, so the label's water-use restrictions shape every decision.
Concepts to master
- Water-use designation. Know whether the water is used for drinking, irrigation, livestock watering, recreation, or fish and aquatic life, and read the label's restriction periods for each. Treated water may be unusable for irrigation or drinking for days or weeks.
- Product selection. Only aquatic-labeled products and adjuvants may be used; a terrestrial surfactant can be toxic to fish and will not perform correctly.
- Application method. Subsurface injection, trailing hoses, bottom-release granules, and surface sprays each place the active ingredient differently in the water column.
- Oxygen depletion. Killing a large mass of vegetation at once triggers decomposition and can crash dissolved oxygen, killing fish. Treat in sections and space treatments out.
- Permits and non-targets. Some states require permits for aquatic applications, and federal discharge permits may apply. Protect downstream water, wells, and sensitive species.
Traps that show up in questions
Treating the entire pond in one pass. Using a general-purpose surfactant. Ignoring irrigation restrictions and damaging crops with treated water. Spraying where water flows out of the system. Forgetting that floating and submerged weeds need different techniques.
Rule of thumb with numbers
Treat no more than about one-third of a pond's surface area in a single operation, wait for the vegetation to break down, and then treat the next section. For a half-acre pond, that is roughly 0.17 acre per treatment.