Insect pests of grain stores

Apparently sound  grain sample		X-rays reveal the  weevil infestation		Grain weevil (Sitophilus granarius)		Weevil larva inside

Once cereal grains are harvested, their intrinsic quality can only be improved by “filtering-out” contaminants, or by selecting and combining standards, to make up bulk lots which more closely approximate to the customer’s requirements.  This is a common approach to, for example, milling wheats, so the buyer – the miller, or baker, - gets what he needs to produce products to a pre-set recipe, or contract specification.  All this is well known and understood. 

However, it is quite easy to not be aware of the changes during storage, with the results that the intrinsic quality drops dramatically.  So an insect or mite infestation in the bulk of grain can have a very detrimental effect on the specification, and can quite easily render the bulk unsaleable, or at least alter its physical and chemical characteristics, often putting otherwise good grains out of grade and reducing their value to simple animal feed standard, or even unusable as feed grains – thus becoming a total loss.

The purpose of this one (or two) day course, is to take the guesswork out of understanding the potential pest spectrum of beetles, moths and mites, and to put on a strong scientific footing the changes that cereal grains undergo during their storage from harvest through to eventual sale, to explain why the grain becomes more and more attractive to the invertebrate pests, and to plan for the possibilities of pest attack, though careful physical and biological monitoring.  The results of such monitoring give the reasons for taking actions, ranging from preventative physical and chemical options, through to the expensive contractor-only fumigation activities.

The course always involves a practical couple of hours in a grain store, looking at the physical storage situation, and weighing up the risks inherent in the storage system, together with assessing the best methods of measuring and assessing temperatures and pest activity by trapping. 

Examples of measuring and trapping systems and equipment, and live samples of the major grain pest species (plus dead specimens and hand lenses) are available to look at, to handle and try during the practical.  The main pest control chemicals are also on site, to discuss how best to apply and with what equipment, plus the current and anticipated restrictions on their use, and which market segments have extra restrictions and why.

Whilst insect and mite identification is important, this aspect is touched on during the course, but a specific one-day course is available for people for whom this element is critical.

Further details from Mike Kelly