One of the best ways to prevent insect infestations is to monitor bin-stored grain every 2 weeks to detect early signs of deterioration or infestation. This section explains several devices you can use to sample grain and check for insects.
Trapping insects
Trapping to determine the presence of insect pests in stored grains is a simple and cost-effective way to monitor for infestations and identify insect pests so that you can make decisions about insect control.
How to use pit-fall traps
Probe pit-fall traps are one of a variety of traps that have been developed for use in stored food. The photo shows two kinds of pit-fall traps:
- A pheromone-baited pit-fall trap (top left corner)
- Open trap (left) and closed trap (right). The trap is closed when in use.
- A pheromone-baited probe pit-fall trap (bottom right corner)
- Intact trap with a string attached to it and the internal components of the trap
Push probe pit-fall traps in the grain at the top of the pile, near the centre. When the grain becomes cooler than ambient conditions, insects tend to migrate to this area of the bulk.
Grain that is in storage should be level, and probe pit-fall traps should be placed in the grain as early as possible. Insert them so that the upper portion of the trap is no more than a few centimetres below the surface. Attach brightly colored twine or rope to the trap so that it can be readily retrieved.
Remove the trap every 10 to 14 days to inspect it for insects. Continue doing this until the grain temperature is below 18°C. After this, monthly monitoring is sufficient. If insects are discovered, use treatments such as aeration; moving and turning the grain; or fumigation or contact insecticide application.
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