The saw-toothed grain beetle, a cupboard pest !
Who is the saw-toothed grain beetle ?
Latin name : Oryzaephilus surinamensis
Order : Coleoptera
Family : Silvanidae
Size : 1.5 to 3.5 mm
Location : kitchen
Period : all year round
What you need to know about the saw-toothed grain beetle
Of tropical origin, this insect can only live in houses. Little known, it is also known as the toothed grain beetle. It mainly infests oats, but also wheat, barley, animal feed, flax and sunflower seeds. It also infests milling and processed products, dried fruit and packaged foods.
You can therefore frequently find it in all your starch-based foods such as flour, bread, biscuits, but also dried fruit, sweets, tea, etc.
The adults are 2.5-3.5 mm long, dark brown in colour and with 6 teeth along each side of the prothorax (hence the name 'saw-toothed').
A real glutton for food
The saw-toothed grain beetle is now the primary insect pest of grain stores in the UK (movement on imported and exported foodstuffs has contributed to the international population spread).
They also infest processed cereal products, dried fruit, dried meats, oilseeds, nuts and rice. When infestations in stores become heavy they cause the grain to heat. This in turn leads to caking, moulding and even sprouting. Both the quality and weight of the grain may be reduced.
Malting barley may be rejected because of poor germination, whilst milling wheat is adversely affected by tainting and discoloration.
The life cycle of the saw-toothed grain beetle
The female saw-toothed grain beetle lays up to 400 eggs, either singly or in small batches, at a rate of 6-10 per day. These are laid in, or adjacent to, a suitable food supply and at a temperature of 20-23 C hatch in 8-17 days to give flattened larvae about 0.9 mm long.
They are yellowish/white in colour, with brown flecks and a brown head. Typical of coleopterous larvae, they have a well-developed head, biting mouthparts and 3 pairs of legs on the thoracic segments. The larval stage lasts 4-7 weeks during which the larvae go through 2-5 moults, attaining a length of 3 mm.
They then construct a cell of food particles and other debris in which to pupate, emerging after 1-3 weeks as adults. On emergence the adult beetles live for 6-10 months, breeding within a temperature range of 17.5-40 C. At 20 C the full life-cycle is completed in 12-15 weeks whilst at 32-35 C it takes only 20 days.
Although they originate from tropical climates, they are sufficiently cold-hardy to be able to overwinter in crevices in unheated buildings.. It can survive the rigours of Canadian winters in unheated installations - that's how resilient it is.
Highly prolific and capable of living for up to 3 years, this insect is particularly dangerous for your food supply.
How do you eliminate saw-toothed grain beetle ?
For optimum effectiveness, proceed methodically :
1. Take a large bin bag and throw away anything that isn't in a totally airtight box, even products that look perfectly fine.
2. Vacuum every nook and cranny of the cupboard or storeroom.
3. Fill a basin with hot water + washing-up liquid + disinfectant (organic, of course!). Using a brush, scrub the entire cupboard, leaving no nook or cranny untouched.
4. When everything is completely dry, treat the entire cupboard with our 4J insecticide diluted to 5% (allow 500 ml for 5m² of treated surface area). If you have large surfaces (more than 25 to 30 m²), we advise you to use the same insecticide, but in its concentrated form. You'll need to dilute it with water in a sprayer to a level of 5% (i.e. 50 ml of pure insecticide for 950 ml of water).
5. Put a few food moth repellent sachets in various places in the cupboard. Yes, that's right! What works on food moths will work on saw-toothed grain beetle ! The margosa and laurel essential oil they contain will radically repel them. Our crawling insect barrier will also keep them at bay.
6. All that's left is to put all your food back in the cupboards, but always in completely airtight boxes.
7. If you still have butterflies flying around, either in the room or in your cupboards, you can get rid of them once and for all with our Ecodoo insecticide or Aries flying insecticide bombs. Finally, in the field of fumigation, we can also mention the Habitat Biovétol fogger. This product will give good results on this type of insect. An insecticide based on active ingredients of plant origin (pyrethrum + geraniol), designed for basic treatment of the home. Highly volatile, the solution settles in the smallest nooks and crannies where parasites and insects live. Immediate and prolonged action, for up to 4 months.
The products you need to combat saw-toothed grain beetle