Besides Lure-And-Trap, How Else Might Pheromones Be Used to Decrease

Besides lure-and-trap, how else might pheromones be used to decrease insect populations?

A) use a pheromone that insects detect as a warning system
B) Spray insect-attracting pheromones right on the plant. The many species of insects that collect will compete and potentially kill each other.
C) Concentrated solutions of pheromones tend to dissolve the chitin of which insect are made.
D) all of the above