Either only the surface of the grain is infested, with indianmeal moth or the entire grain mass is infested with one or more other insects. Dealing with the surface infestation is enough of a chore, but controling insects deep within the grain mass is a much more difficult and dangerous job. If you have an infestation within the grain mass you are limited to two alternatives. You can move the grain to an empty bin or other container and apply a grain protectant as the grain moves or you can fumigate the grain in the bin . Applying a protectant during a move is often impractical and is the least effective of the two alternatives.
Fumigation is usually the most effective control IF it is done correctly.
It is also one of the most dangerous activities you can be engaged in on the farm.