Aquatic Pest Control
Aquatic pest control manages algae, submerged and emergent weeds, and nuisance fish or invertebrates in ponds, lakes, ditches, and other waters. The exam tests water-use restrictions, permits, fish toxicity, oxygen depletion, application math, and environmental protection.
Core rules
- Identify the target and water use: drinking water, irrigation, livestock, recreation, fish, or drainage. Label restrictions vary by use.
- Many aquatic applications require a state or federal permit; do not treat without required authorization.
- Treat a portion at a time when risking oxygen depletion; decaying weeds consume oxygen and can kill fish.
- Herbicides differ for algae, floating weeds, submerged weeds, and emergent weeds; misidentification wastes product and can harm nontargets.
- Respect irrigation and drinking-water setback periods and avoid drift to nontarget water.
- Protect fish, amphibians, and wildlife; follow label rate, surfactant, and application method limits.
Worked example
A pond is 1 acre with an average depth of 6 ft = 6 acre-feet. Label rate is 2 lb product per acre-foot. Product is 2 times 6 = 12 lb. If the product is 50 percent active, active applied is 6 lb. Reasoning: acre-feet combine area and depth; treating by surface area alone overdoses deep water. Measure depth at several points, average, and calculate before mixing.
Traps
- Treating the whole pond at once and causing a fish kill from oxygen loss.
- Using a lawn or crop herbicide that lacks an aquatic label.
- Ignoring irrigation restrictions that can damage crops.
- Calling duckweed algae and choosing the wrong product.