Which aquatic pests may require pesticide treatment?

Pesticide treatment may be necessary for controlling specific aquatic pests that can harm ecosystems, human health, or recreational activities. Algae, for instance, can overgrow in water bodies, leading to harmful algal blooms that produce toxins detrimental to aquatic life and people using the water for recreational purposes. Mosquitoes are notorious vectors for diseases, making control measures essential in areas where they breed in water. Invasive aquatic plants can choke out native vegetation, disrupt habitats, and alter the ecological balance of waterways.

By focusing on these specific types of pests, the answer highlights the targeted approach needed to manage the aquatic environment effectively. Other options include organisms that are generally beneficial or natural parts of the ecosystem, making them less likely to require pesticide treatment.