Which method is not useful in eliminating breeding places for insects?

The method that is not useful in eliminating breeding places for insects is fly strips. While fly strips are effective for catching adult flies, they do not address the root of the problem, which is the breeding sites where flies and other insects reproduce. Effective pest control involves proactive measures to reduce the conditions that allow insect populations to thrive.

In contrast, the other methods listed contribute directly to eliminates potential breeding environments. Regularly washing surfaces helps remove food particles and spills that can attract insects. Proper food storage ensures that food is not left out in the open, providing a target for pests. Fly traps, while intended for capturing adult insects, also create a cleaner environment by reducing the adult population, which can further limit breeding opportunities. Thus, addressing pest problems requires a comprehensive approach that eliminates breeding places rather than merely catching insects after they have already become a problem.