Final answer:
ACUs are pre-treated with insecticides such as DDT and carbamates to protect from disease-carrying insects. Biological control tools are also used for insect control.
Step-by-step explanation:
ACUs (Army Combat Uniforms) are pre-treated with insecticides that provide protection from disease-carrying insects. One example of an insecticide used is DDT, which was a highly effective insecticide for malaria control after World War II. ACUs may also be treated with carbamate insecticides or biological control tools to control insect populations and resistance.