There are many signs that a structure might be infested by grain beetles. Unfortunately, most homeowners discover an infestation when they find grain beetles inside of common pantry products. Grain beetles are also known to crawl along shelves and counters, so an infestation might also be discovered that way. Homeowners can usually discover an infestation on their own because grain beetles really only cause problems in pantries. If an infestation is discovered, it might be a good idea to hire a professional pest control expert.