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Grain Beetle

How do I recognize a sawtoothed grain beetle?

The sawtoothed grain beetle is one of the most widespread of all stored product pests. This slender, flattened reddish-brown beetle measures two to three mm(1/10″) in length and gets its name from the presence of six tooth like projections on its thorax (middle section). There are numerous other stored product pests that closely resemble the sawtoothed grain beetle and whose life history and habitat are very similar. For this reason, this Pest Alert addresses stored product pests under the term “grain beetle”.

Do grain beetles cause damage?

Yes. From the point-of-view of the manufacturer of food products, such as flour, rice, meal, cereals, sugar, macaroni, dried meats, coffee and tobacco, the presence of grain beetles renders these goods unpalatable and unsalable. As well, an infestation will create conditions suitable for the growth of destructive moulds. In the home, an unchecked infestation can spread to other packaged foods and to foods debris on shelves.

Are grain beetles hazardous to humans?

No. The presence of grain beetles does not constitute a health hazard.

When are grain beetles most common?

Grain beetles favour high temperatures and high humidity, and are therefore more active during summer months.

Where do you find grain beetles?

Because they infest a wide variety of products that are of plant and animal origin, grain beetles can originate at the manufacturing, storage or retail levels.

What are their breeding habits? Do grain beetles multiply quickly?

The female grain beetle lays from 45 to 285 eggs per year, either singly or in small batches. Eggs hatch in three to 10 days and mature in approximately 50 days. Since an adult grain beetle can live up to three years under ideal conditions,an infestation can number in the hundreds of thousands.

Can weather conditions affect the size of a grain beetle infestation?

Yes. Given the ideal conditions of moisture and heat, breeding increases dramatically.

Can I do anything to prevent an infestation of grain beetles?

Yes. Regular inspection of stored products and immediate disposal of suspected sources of infested goods, together with good housekeeping methods will minimize the incidence of a grain beetle infestation. Proper ventilation of dried foodstuffs is essential to reduce humid conditions favourable for the growth of a grain beetle infestation.

If I have an infestation of grain beetles, what can I do to eliminate them?

Your local PCO Service and Products Centre has products and kits specially formulated for the control of grain beetles. Due to the rapid breeding ability of these insects, and their proximity to food and food preparation surfaces, a single control method may not be effective and an integrated program conducted by a PCO professional will be required.

Please remember all pesticides can be harmful if misused. Follow the label directions carefully.