Which of the following is NOT one of the four main pest groups?

• A. Bacteria
• B. Weeds
• C. Invertebrates
• D. Disease agents or pathogens

Answer: (A)

The main idea is how pests are grouped for management. In most pesticide practice contexts, pests are categorized into four groups: weeds, invertebrates (such as insects and other spineless animals), disease agents or pathogens (like bacteria, fungi, viruses), and vertebrate pests. This helps tailor control methods to the type of pest.

Bacteria are not listed as a separate pest group; they are one of the disease agents or pathogens. So they fit under that category rather than forming their own group. The other options—weeds, invertebrates, and disease agents or pathogens—are each one of the four main pest groups, making bacteria the correct item that is not a main group by itself.