Final answer:
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) is the law that prohibits the use of any registered pesticide in a manner inconsistent with its label directions, as administered by the EPA.
Step-by-step explanation:
The law that prohibits the use of any registered pesticide in a manner inconsistent with label directions is the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). This act is administered by the Environmental Protection Agency (EPA) and requires all pesticides to be registered and approved before being sold in the United States. The label on each pesticide includes usage instructions which must be followed to ensure safe and effective application while minimizing risks to human health and the environment. Not adhering to these label directions can lead to legal repercussions under FIFRA.