Weevils are members of a diverse family of beetles. These insects are less than a centimeter long, with hard black or brown bodies and long snouts. The wheat weevil — also called the rice weevil — frequently infests stored grains like cereal and pancake mix, and is commonly found in flour. Weevil infestation occurs when weevils lay their eggs in grains, resulting in hundreds of larvae that feed off the grain. Once flour has been infested with weevils, it is nearly impossible to eliminate them, but it is relatively simple to prevent weevil infestation.
Put flour in the freezer. Remember to defrost it for a few hours before you want to use it. Weevil larvae cannot survive freezing temperatures. If you use flour often enough that freezing is inconvenient, try placing the flour in the freezer for a few hours once a week. This will prevent weevil larvae from hatching.
Throw away any items that have been infested by weevils. This includes anything -- like wax or contact paper -- used to cover counter tops or drawers, as well as boxes, bags and items that have come into contact with the weevil-infested flour. Weevils only need a very small piece of flour in order to lay their eggs, and the eggs aren't visible to the naked eye. Consequently, anything that has weevils have contacted can spread an infestation. Clean out cupboards and cabinets where the weevils have been.
Place all grains and flour in airtight containers. Plastic bins and zipper bags work well and are inexpensive. Weevils can't get into sealed areas, so as long as there aren't already eggs in the flour, airtight containers will keep out weevils.
Put sticks of spearmint gum in your pantry. Weevils are repelled by the smell and taste of spearmint and will avoid the gum. Tape spearmint gum to the inside of the flour container, as well as on the lid and outside of the container.