Which of the following is NOT a category of rodenticides?

The correct answer is that "biological" is not a category of rodenticides. Rodenticides are chemical substances specifically formulated to control rodent populations, and they are categorized based on their mechanism of action and composition.

Natural rodenticides refer to substances derived from natural sources that can effectively kill or repel rodents. These might include certain plant extracts or essential oils that demonstrate rodenticidal properties.

Fumigants are chemicals used to infiltrate spaces and kill pests through vaporization; while they may be used in broader pest control strategies, they are not typically classified under the same category as rodenticides, which are more focused on direct ingestion by the target organisms.

Anti-coagulants are a specific class of rodenticides that work by preventing blood from clotting, ultimately leading to the rodent's death due to internal bleeding. This category is common and widely recognized in rodent control practices.

In contrast, biological methods or agents generally refer to the use of living organisms or natural processes for pest control, which do not fit the specific chemical categorization of rodenticides. Therefore, while biological controls can be part of an integrated pest management strategy, they are not classified as rodenticides themselves.