Introduction

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Insect Control in Stored Grain
Prevention
Clean in and around storage facilities. Grain storage facilities, and the area around storage facilities, should be cleaned
thoroughly prior to storing grain.
Clean equipment used to move grain. Grain left in equipment throughout the summer months can result in new grain
that is being placed into storage becoming infested. Combines, truck beds, grain wagons, augers and other equipment
used to move grain should be cleaned of grain residue. Other potential sources of grain infesting insects include livestock
feeds, old seed bags, spilled grain, etc.
Inspect grain storage facilities for signs of deterioration, especially for leaks or holes through which insects or rodents
can gain access to the stored grain. Moving and storing the grain in clean facilities will eliminate one source of infestation.
However, grain stored for long periods of time still has the potential for renewed infestations.
Treating storage facilities. Depending on the commodity to be stored, storage facilities may additionally be sprayed or
dusted, if needed, with a recommended insecticide before storing grain in the bin (e.g. malathion, diatomaceous earth or
cyfluthrin – refer to product labels for details). Note: some commodities, such as canola, flax and sunflowers, should not be
stored in facilities recently treated with malathion or cyfluthrin (Tempo).
Dry and Cool Grain. Ideally, the grain should be dry before being put into storage, and cooled as quickly as possible.
For long-term storage, producers are urged to lower the grain temperature below 15°C as soon as possible after the grain
is placed in storage. At 15°C the stored product insects stop laying eggs and development stops. Aeration systems used
during the night immediately after harvest should have the grain below 15°C in about 2 weeks. Grain that is not moved or
aerated after harvest can remain warm enough to allow insects to survive the winter. Convection currents arising from this
warm air can also promote condensation, sprouting (heating) and mould growth in unmanaged grain. These conditions are
very attractive to stored product pests and support their development.
Once the grain mass is cooled to the desired temperature, fans should be sealed to prevent unwanted air migration through
the mass that could result in early grain mass warm-up. Cold grain has a longer storage life than warm grain.
Note, however, that under cool grain temperatures, insect movement is reduced to the point that some insecticides may
not be effective.
Monitoring for Insects
Bin probe and Sieves: Stored grain insects can be monitored by taking grain samples with a bin probe, sieving the grain,
and looking in the dockage for Insects.
Probe Traps: Another means of detecting insects in stored grain is through placing probe traps (such as the WB PROBE II
Trap from Trece) in the grain and monitoring them. Often the first indication of an infestation will be found near the top
centre of a storage bin, and therefore, this is where traps should be placed. Monitoring should take place once every
7-10 days during the onset of storage (first 60 days) and then the frequency of monitoring may be adjusted.
Identifying insects in stored grain
Correct identification of insects found in stored grain is important in determining the most appropriate control methods.
Some of the insects found in stored grain feed directly on the grain, referred to as primary pests, while others feed on grain
that is damaged or going out of condition, referred to as secondary pests.
Primary insect pests
Insects that feed directly on the grain include rusty grain beetles, red flour beetles, and sawtoothed grain beetles.
The rusty grain beetle is the most common stored product insect. Heavy infestations of this insect cause grain to heat and
spoil.
The red flour beetle is another common insect pest of stored grain in the prairies. Red flour beetles cannot feed on
undamaged, dry seed with less than 12% moisture content. They prefer grain dust, broken grain and milled stocks.
Sawtoothed grain beetles are more common in stored oats than in stored wheat and barley.
Insect Control