How to Prevent Insect Infestation at a Grain Store…

If you are responsible for the running and maintenance of a bulk grain store, you probably dread the very thought of having a pest infestation, and take a great deal of care to avoid it. Time and money is spent making sure a store is clean before the grain is delivered, and controls and measures are taken to create an environment that makes it hard for insects and pests to successfully thrive and wreak havoc. It’s normally worth the extra expense, because it costs less than cleaning a large amount of infested grain, but in reality is that really sufficient?

Experience suggests, a grain store will test for insects when a bulk delivery arrives, by sieving a relatively small sample of between 500g to 1kg, and assessing the screenings by eye. But realistically, how reliable is this method? It greatly depends on the size of the sample, and the size of the potential incoming infestation...

 Let’s just consider a truck arrives at your grain store with 20,000kg of grain, in which there are insects at a ratio of 1 insect to every 10kg.

If you extract a 10kg bulk sample from the load, and screen only a 1kg sub sample for the presence of insects, you would only have a one in ten chance of that sample containing an insect, because you are testing such a small representation of the entire load!

 If that 1kg sub sample is the one with an insect, you then have to rely on the operators spotting it (providing they have sieved sufficiently to shake the insects from the grain). 

 If they don’t notice it, or have tested a sample without an insect, they would in effect have just accepted a delivery of 2000 insects!

Suppose that load is then added to a storage unit that already contains 80,000kg of previously clean grain. Unfortunately by not screening effectively at the point of entry to the grain store, you would now have 100,000kg of infested grain, this could potentially be even more if you still add additional product to the silo...