What type of chemical is a piscicide?

A piscicide is specifically defined as a chemical designed to control or eliminate fish populations, particularly pest fish species that may harm aquatic ecosystems or compete with desirable fish species. The term "piscicide" is derived from the Latin word "piscis," meaning fish. These chemicals are used in various contexts, such as fisheries management, conservation efforts, or recreational fisheries, where controlling fish populations is necessary for maintaining ecological balance or improving the quality of a fishing environment.

The other choices do not relate to piscicides. The option about controlling insect pests refers to insecticides, which target insects. Similarly, the reference to controlling disease in plants is associated with fungicides or acaricides, depending on the specific organism involved. Lastly, soil enhancement relates to fertilizers or soil amendments, not to the targeting of fish populations. Understanding these distinctions clarifies why the correct answer pertains to the control of fish, emphasizing the specific role of piscicides in managing aquatic environments.