The flour mites
Have you spotted flour mites in your kitchen or laundry ? Are they starting to invade your home and you don't know where to start ? A flour mites invasion can become complicated if you don't act quickly. In this dossier, you'll find a range of answers and products to help you combat this invasive insect.
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Latin name : Acarus siro, formerly known as Tyroglyphus farinae
Order : Acarina
Family : Acaridae
Size : 0.5 mm to 1 mm
location : All storage areas, especially the kitchen
Period : All year round
What you need to know about the flour mite
Unlike the dust mite, which is not visible to the naked eye, the flour mite is, like the tick, one of the few mites that can be seen without the aid of a microscope. In fact, a few centuries ago, it was considered to be the smallest animal known.
The flour mite is one of the so-called "storage" mites. It often infests places where food is stored. It can therefore be found in grain silos as well as in domestic kitchens.
Very small in size (less than 1 mm), the flour mite generally goes unnoticed until the day when favourable conditions such as abundant food and high heat and humidity allow it to multiply. The life cycle takes 10 days, at 23°C and 87% relative humidity.
From then on, they become visible in large numbers, and what might be mistaken for living whitish dust is in fact a flour mite colony. However, it is normal to have wax mites in your home. Like other house dust mites, they can be found in many homes. Although its excessive proliferation can be disturbing, it is completely harmless... except for people with allergies.
Although they have a preference for flour, grains and cereal flakes, they can also feed on dust, dander and other human and animal detritus, as do house dust mites. Generally speaking, they concentrate most often in the kitchen, where they are likely to find flour, flour-based products and seeds, which are their staple foods. But it will also like pet food, cheese and ham.
Infested products are covered in a layer of grey dust. Spoilt and often bitter-tasting, they become completely unfit for consumption. Food contaminated with flour mite can lead to serious allergies, asthma attacks and other pathological conditions. All contaminated products must be discarded.
Development from egg to adult (egg, larva, nymph, imago) takes around ten days at normal room temperature.
Adults live for 30 to 50 days. The female lays around 200 eggs during her lifetime.
According to the literature, A. Siro can be confused with A. Farris or A. immobilis. These three species are morphologically very similar. If we want to be purists, A. Siro is a species of mite because it has a few distinct characteristics. One last detail : the larva has 6 legs like the insect and the adult has 8 like the mite!
While favourable conditions can accelerate its development (a pair of Acarus Siro can have offspring of 2,500 individuals in a month), unfavourable conditions are not enough to make it disappear immediately.
Thanks to a state of lethargy, it is able to survive for several weeks until milder conditions return. It can also attach itself to an insect, such as a flea, in a phoretic association.
Storage mites can contaminate processed foods.
Seven categories of cereal-based food products purchased in shops in the UK were examined :
Mites were found in 21% of the 571 samples examined shortly after purchase, and in 38% of the 421 samples examined after 6 weeks' storage.
Most samples contained less than 5 mites, a few more than 20 and one contained 428 mites.
The most common species were found : Acarus siro, Tyrophagus putrescentiae, Lepidoglyphus destructive and Glycyphagus domestiques.
Beware of storage mites : risk of allergies
Storage mites are a major allergen.
A Wisconsin study showed that the most common allergies were due to dust mites (21.6%) and storage mites (11.2%). Among storage mites, the most widespread sensitisation was due to L. destructor, followed by T. putrescentiae, G. domestiques, Chortoglyphus arcuatus, and Acarus siro.
With regard to allergic reactions, numerous studies have been carried out and it has been found that Acarus siro can cause symptoms of occupational allergy in farmers and bakers, but also in non-agricultural populations. No region of the world is immune to this type of mite. The same is true of Denmark, Poland, Cuba, Spain, Chile, Bavaria, etc. (see study on this site).
In kitchens, flour mite appears mainly as a result of 3 factors
1 - storage of accessible foodstuffs
2 - temperature between 25 and 30°C,
3 - humidity levels above 70%.
These conditions are often met during stormy summers or in heated, poorly ventilated premises. Heat and humidity also encourage the development of fungi, which storage mites also feed on.
As a preventive measure, flour mite infestations can be avoided if
- if food is stored in hermetically sealed boxes or containers,
- if rooms are properly ventilated to limit humidity.
Rule No. 1 (which also applies to all kitchen pests) is to eliminate all sources of food. To do this, you need to :
1 - Put pet food out of reach at night,
2 - Dispose of your kitchen waste in plastic bags placed in hermetically sealed bins,
3 - Store your food in hermetically sealed tins,
4 - Don't leave crumbs or dirty dishes lying around,
5 - Clean your kitchen regularly. Vacuum the floor and wash with a disinfectant/fungicide product the floors, worktops, cooker, etc.
In the event of an infestation, start by applying the above preventive rules. Then tackle the underlying problem.
Basic treatment against flour mite
To eliminate flour mite properly, we suggest you use 2 of our products: 4J insecticide + Ecodoo insecticide.
It should be sprayed on all surfaces where the insect is present (including inside cupboards) but also, if you can, in all remote and less visible areas (behind and under cupboards, for example).
You can also opt to prepare a washing water with this concentrated insecticide added, so that you can spray all the surfaces directly (dilute to a minimum of 2% = 1 litre of water + 20 ml of concentrated 4J). You can use this preparation to wash everything. Be careful not to apply to surfaces in contact with food (or rinse after drying).
1 - Take a large bin bag and throw away anything that isn't in a totally airtight box, even products that look perfectly clean.
2 - Vacuum every nook and cranny of the cupboard or storeroom,
3 - Wash all surfaces, leaving no nook or cranny untouched, either by spraying with 4J insecticide or by washing with the insecticide solution (mop or sponge).
4 - Before putting your things back in the cupboards, as a precaution, it's best to wash everything either in a basin or in the dishwasher. This rule applies not only to your crockery, but also to your clothes. Anything that can't be washed can be treated with our Ecodoo insecticide. Proceed as follows: Put the items in a bin bag, spray the inside with insecticide, close tightly and leave for at least 48 hours. If the objects can stand heat, you can also put them in the oven.
After the cupboards, tackle the dustbin, the underside and the back of the furniture, fridge, oven, microwave, etc.
There shouldn't be a single spot or nook in the kitchen that hasn't been cleaned and treated with the insecticide solution. We treat from the floor to the ceiling, including the walls and electrical appliances. The aim is not to eliminate the flour mite 100%, but to significantly reduce its population.
Good cleaning, removal of all food, good ventilation and treatment of all surfaces with our insecticide should lead to a gradual reduction in their population. Cleanliness being the number one rule, don't hesitate to wash your floor, work surfaces, etc. regularly and spray insecticide on everything you see. The more thorough the treatment, the quicker they will disappear. Normally, flour mites should disappear completely within a few weeks. If this is not the case, the treatment was incomplete and they are still finding food !
Go directly to the detailed product sheets for products to combat flour mites (or storage mites).
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