Best Management Practices Series: Pest Management in Grain Processing Facilities

Grain storage facilities present unique challenges for facility and QA managers and the professional pest management companies that service them. The pests that threaten grain products are unique to these facilities and require specialized control and prevention measures.

Rodents are often the primary pest of concern in grain storage facilities. The house mouse, Norway and roof rat are the three most commonly encountered rodents in grain or food processing operations.

Rodents can be found on both the exterior and interior of a facility and can make their way inside through openings in the foundation, loading dock or entry doors that are left open for extended periods of time and within shipments of food material including a wide variety of grains.

When it comes to insects, tolerances and action thresholds will vary depending on the type of facility and the client. Grain that is brought to the facility for storage will often contain insects that initially infested the product before it was harvested. If grain is brought to the facility from another storage facility it may also be infested.

Insects that attack grain follow a succession. First, internal feeders such as the maize weevil, granary weevil and lesser grain borer will attach the undamaged kernels. After they feed on the grain, damaging it and scavengers such as the red flour beetles will feed on the damaged kernels. 

Finally, after this, the grain will be heavily damaged and generally have a higher moisture content, at which point insects such as the flat and rusty grain beetle will be attracted to it.

In addition to the grain, insects infesting the structure may be living on the grain dust and spillage. Insects such as the red and confused flour beetle commonly feed on the dust. Warehouse beetles are commonly found outside of the facility in rural areas, and will enter the structure and feed on dust or dead insects.

The Sprague Pest Experts have assembled the following list of the most commonly encountered pests in grain processing facilities and where they are most likely to be found:

Lesser Grain Borers, Granary Weevils, Maize Weevils – Always associated with whole grains. Found in grain storage bins, head houses and conveyor tunnels under grain bins. These are important pests in grain storage facilities.

Red and Confused Flour Beetles – Found in the grain itself, in electrical boxes, underneath pipe insulation, in floor cracks, in screw or bucket conveyors, in floor cracks in head houses and airlocks. Also often found in the joints of flexible connectors between equipment.

Indian Meal Moths (other stored product moths) – Under the lids of storage bins, under and inside equipment, in unused equipment. Virtually anywhere there is an accumulation of stored or processed product dust.

Warehouse Beetles – Window sills where dead insects accumulate, unmaintained insect light traps, electrical boxes and panels, and head houses of grain storage bins.

Rusty and Flat Grain Beetles – In some areas these are the primary stored grain pest. These will follow the flour beetles in attacking damaged grains. They can often be found in structures feeding on grains that are supporting fungus.

Pest Birds (Pigeons, English House Sparrow, Starlings) – Exterior, roof, rail sidings, weighing scale houses


Agriculture, Food Processing & Manufacturing