The most evident cause of foreign grain beetles infesting your home is the growth of mold or fungus at any location. This is because both mold and fungus serve as food for the beetles. Get both the aforesaid elements removed right away and ensure that neither mold nor fungus grows at your home. Moreover, to keep your home free from moisture, get any leaky pipes repaired and ensure proper ventilation. Your aim should be to remove all factors that can facilitate the build-up of moisture.
Upon the first sign of foreign grain beetles infestation, get the areas surrounding baseboards, as well as the space between electrical outlets and walls, sprayed with aerosol containing pyrethrins. As an alternate to aerosol containing pyrethrins, you can effectively use dry residual dust.
Wait until your house is free from mold and mildew and is completely dry from the inside. New houses can remain affected by moisture for a period of up to four years. As foreign grain beetles can be very difficult to get rid of, you may have to live with the problem for over four years if you have moved to a new house just recently.
Beetles that come out of hiding and reveal themselves should immediately be removed with a vacuum cleaner. However, this technique would have absolutely no effect on the beetles hiding inside the walls.
If the problem gets out of control, your best option would be to hire a professional exterminator.