The sucker tenebrion: insect of flours

The tenebrio molitor is an insect of the order of beetles, of the tenebrionid family. It seems to be of European origin, but it is found all over Quebec and around the world.
It is also known as the largest insect pest of whole and ground cereals.

It is commonly found in our warehouses, bakeries and other food storage areas. It sometimes infests our homes, if there are dark, damp places, as well as food.

What does it look like? What is its life cycle? How can we prevent its intrusion? How can it be eliminated? So many questions that Animal Alert answers.

Description of the miller’s tenebrion

The adult sucker is a robust and shiny insect. The color of his body varies from dark brown to black. This is where the name “Tenebrion” comes from, the term “miller” coming from the fact that it can live in very dry stored foodstuffs such as flour.

The sucker tenebrion is between 15 and 18 mm long. The male is generally smaller and more slender than the female.

This insect has wings, but does not use them much.

Lifecycle: how do they reproduce?

The sucker tenebrion is a holometaboleinsect, that is, it goes through the 4 stages of development:

• The egg,
• The larva,
• The nymph,
• adult.

Its breeding cycle is based on environmental conditions. It is done in two or three months if the surrounding temperature is between 25 and 27 degrees.

The female lays and lays her eggs directly in cereals or at the edge of the grains. A female sucker’s egg can range from 100 to 500 eggs.

The egg

The egg of the sucker tenebrion is particularly small (1.8mm). It’s white and shiny. Because of its whitish colour, it is very difficult to recognize it in flour.

It will take 4 to 18 days for the larva to come out.

The larva

The sucker tenebrion larva is shaped like a worm. It can live in very dry stored foodstuffs, such as flour. For this reason, it is commonly referred to as a “flourworm.”

When it comes out of the egg, the sucker tenebrion larva measures 2 mm and is white in colour. It will gradually take on a golden yellow hue, and will reach a size of 25 to 30 mm.

It will take 10 to 16 moults to reach the nymph stage.

The nymph

The nymph of this beetle is about 16 mm long. It stays at this stage for three weeks before taking its adult form.

The adult

The young miller tenebrion has at first a reddish brown or beige-orange color. The black color will not appear until a few years later. The adult lives about 2 or 3 months.

How are they harmful?

The miller’s tenebria infest the mills:

• providers,
• Silos
• grain cells,
• provenderies,
• Warehouses
• chicken coop litter,
• Mills
• bags of animal feed,
• waste falls,
• and all the dark, damp places in our buildings.

They feed on decomposing grains and moist or degraded milling products, as well as healthy products:

• raw cereals,
• sounds, casts,
• flours, etc.

They also do not disdain meat, organic materials (feathers, dead insects, etc.), bread, nuts and biscuits

The larva digs holes in the wood and cardboard.

Millers can be vectors of parasites.

How can an infestation of suckers be prevented?

Do you want to prevent the miller’s tenebrion from massively attacking your food? If so, follow these 3 tips:

• Seal the shopping bags. Especially when they contain cereals, it doesn’t matter if they are wet, decomposing, ground or whole.
• The sucker carer loves dirty areas, make sure to keep clean in your warehouses, silos, other storage areas, and in your homes.
• Make sure the garbage cans are always emptied,
• Do the housework frequently,
• Aerate very often.
• If you notice that some bags of cereal have already been infected, pack them in tightly sealed plastic bags. Then throw them in the trash.

Professional exterminator solutions

You can try to eradicate an infestation of suckers. If we want to guarantee their complete extermination, it is better to call in a professional exterminator.

The sucker beetle exterminator will use solutions deemed effective in the destruction of all grain pests: thermal treatment eradication, pneumatic conveyor disposal and chemical treatment eradication.

1. Thermal treatment eradication: Exterminators use grain dryers to subject grains to high temperatures. At the end of this heat treatment, the exterminator immediately cools the grain. This prevents it from heating, degrading or being invaded again by the suckers.

The exterminator can also expose the grains to very low temperatures. For example, exposure of grains to -5oC eliminates these pests at all stages of their development.

1. The extermination by use of grain vacuum cleaners or pneumatic conveyors type cyclone: the percussion effect generated by the cyclone kills the suckers.
2. Destruction by chemical treatment: here, the exterminator uses insecticides. It can use:

• Diatom soil: it kills the insect by dehydration,
• Malathion: it kills the insect by impeding the functioning of its central nervous system,
• Phosphine: It is found in forms such as aluminum phosphorus, magnesium phosphorus and gaseous phosphine. The exterminator applies them by fumigation. This well-used product is effective against all stages of the development of the sucker tenebrion.
• Carbon dioxide: it is applied to the grain in the gaseous state.
• Methyl bromide: used as a pre-shipment treatment and quarantine of import/export foodstuffs.

To learn more about these different solutions, visit this page of the Canadian Grain Commission.

Hire a grain pest exterminator

However, beware! Know how to distinguish the professional exterminator from the amateur, because only he can guarantee a definitive and complete destruction of the suckers:

• He gets rid of these attackers in compliance with Environment Canada regulations, as attested by his permit from the Quebec Ministry of Sustainable Development with the inscription C5: Extermination.
• He worked like this: his certified professional extermination technicians quickly arrived at the site of the invasion.

Their goal: to confirm that this is indeed a massive attack of miller’s groans, to measure the intensity of their aggression, and to determine the sources to neutralize them.

He then offers you a treatment adapted to the strength of the invasion.

Finally, it informs you or trains you on the precautions to be taken to protect you from a future invasion of the suckers.

• It uses unidentified vehicles and remains discreet in all interventions.
• He offers you a written guarantee on the effectiveness of his treatment against themassive attack of miller’s tenebrion.
• It knows how to choose insecticides suitable for your infestation and makes it a safe use. Rest assured: if he has a permit from the Quebec Ministry of Sustainable Development, it means that he is paying attention to all of this.

And you? Have your cereal and other foodstuffs ever been invaded by the suckers? Have you been able to get rid of it? If so, how did you do it? Share your experience with us in the comments below.