Grain weevils are pests that feed on and destroy stored seeds and whole grains. The simplest way to get rid of these pests is to locate and throw away any of the infested grain that they are feeding on, and then to carefully clean the storage area afterward. It is also possible to kill grain weevils, which are sometimes also called snout beetles, by exposing them to extreme heat or cold. In addition, insecticides do have an effect on getting rid of these pests.
Until there is a presence of adult weevils, it is not always apparent that grain is infested. This is because female weevils lay their eggs in grains; in doing so, they drill holes and then cover them up again. Adults emerge from these grains, but larvae are hidden inside until they become adults, at which point they drill holes to get out. To see if grain is infested, look for these exit holes. After disposing of infested grain, cleaning the area in which it was stored will get rid of any lingering weevils.
Discarding grain might not be a practical choice for some people. To kill eggs and larvae, infested grain can be heated in the oven or microwave, as well as frozen. This process does have a drawback, though, as extreme temperatures reduce grain germination. Decreased germination can be unacceptable for those who anticipate using the seeds for planting.
Insecticides are generally dangerous and do work, but only to a certain degree. They have to come into direct contact with the weevils in order to be effective. If desired, insecticide can also be used as a prevention measure. A spray of an insecticide that contains pyrethrins provides a protective layer over the seeds or grain, inhibiting female grain weevils from depositing their eggs. Large infestations that cannot be eliminated might require a call to a professional for fumigation.
Grain infestations can be caused by any of three types of grain weevils: rice, granary and maize. Rice weevils and maize weevils are similar in appearance; they are dull red to black with four red to yellow markings on the back, though maize weevils are the bigger of the two. Both these species can fly, which is not the case with granary weevils. Granary weevils are red to black in coloring and larger than both rice and maize weevils. Grain weevils are a nuisance all over the world.