Other pests of stored foodstuffs are beetles

Pests of stored products are most commonly found in dry products of plant origin: wholemeal, flour, pasta, nuts, spices, peas, dried vegetables and fruit, dried flowers. Animal products can also be vulnerable: dried meat, fish products and cheese. They also damage museum collections of plants, insects and animals (stuffed animals).

Why are they pests?

Caterpillars contaminate products.
Damage to the product ⎯ it is no longer usable.

Which areas are relevant?

Home
Food industry
Storage areas for foodstuffs and their raw materials
Logistics sector
Catering establishments
Tobacco industry
Nature museums
Accommodation service companies

What do they harm and who do they harm?

Dry products of plant origin in storage
Museum collections of plants, insects, animals (stuffed animals)
Dried herbs
Dried meat and fish products
Cheese and cheese products
Tobacco

Key attributes

At temperatures below 13⎯15 ºC their development stops. In unheated areas or in places that are unfavourable for development, the moth usually develops once a year.
Eggs are placed on foods or raw materials.
They hide in wall cracks, in dark places that are hard to reach.
Almost all stored product pests are adapted to feed on food with very little liquid content. These pests can enter warehouses from the outside through open windows and doors, through cracks in walls, through ventilation and other openings, from adjacent premises, or by migrating from contaminated to non-contaminated products. They usually arrive with already infected produce.

Wheat weevil and rice weevil. These beetles damage perfectly healthy grains (they are the primary pests and contaminants). In absence of cereals, these beetles feed on pasta, beans, chestnuts, acorns and dry dog and cat food. Weevils are found in warehouses, mills, ships and living quarters. In warehouses, weevils usually settle in the middle of the grain pile, where temperatures are higher. In the case of weevil faeces contamination, the fermentation process raises the temperature in the grain pile and causes water condensation.

Drugstore beetle. Food: starchy solid products such as biscuits, old dried bread, dry soup concentrates, pasta, dry dog and cat food. These pests spoil and contaminate raw materials and products that have been stored for a long time. Adult beetles can penetrate paper, plastic and even aluminium barriers ⎯ damaging the packaging. They spread during the transportation of products.

Flour beetle, red flour beetle and destructive flour beetle. The optimum development temperature for all flour beetle species is 30⎯35 ºC. Development almost stops at temperatures below 20 ºC. They feed mainly on cereals. These beetles are secondary pests because they feed on products that have already been damaged, most commonly ⎯ mould fungi, which appear when products are first damaged. They can eat flour, bread, biscuits, pasta, beans, dried fruit, spices, chocolate and other fruit, vegetable and cereal products. In empty warehouses, they feed on product residues in cracks in flooring and wall crevices.
Mealworm. Feeds on products of plant and animal origin. Lives in dark places. Their role as pests is limited. Only products that are extremely unattended and stored for a very long time can be damaged or spoiled.

Bean weevil. The female lays about 50 eggs on the beans. The hatched larvae burrow into the bean (several larvae can develop per fruit) and feed on it. In the Lithuanian climate, bean weevils are found only in stored beans. In warm summers, the bean weevil is the main and most damaging pest of beans. The beans are gnawed and lose their marketable appearance as well as the nutritional value. Round holes are punched in the walls of the bean pods. Most of the time, it comes to us with contaminated produce.

Sawtoothed grain beetle. Feeds on grains, nuts, etc., but these beetles cause less damage than weevils. In empty warehouses, they feed on grain residues in cracks in the flooring and in wall crevices. They damage products by contaminating them and making them unusable. Sawtoothed grain beetles are often found in living areas and cause discomfort. They spread during transportation of goods, foodstuffs, and raw materials.

Pyralid moth. Adults fly well. Beetles are active at night. At temperatures below 20 ºC, their development stops. The larvae are killed if the temperature indoors is below 13 ºC for an extended period. Only the larvae of the pyralid moth are harmful to stored products. They eat tobacco products, but may also eat peanuts, biscuits, cocoa beans, spices, rice, dried fish and fishmeal. In empty warehouses, they feed on food residues that accumulate in cracks in flooring and wall crevices. They spoil tobacco and its products and other stored products. Tobacco stored for a long time is more susceptible to these pests than fresh tobacco. The pyralid moth lives naturally in tropical and subtropical climates. In Lithuania, we find it in warehouses, production facilities and other warmer areas. The pyralid moth is introduced to new locations with tobacco and its products, therefore, it spreads with the raw material brought in. The development and reproduction of these beetles is particularly dependent on temperature.

PEST CONTROL involves the protection of human health, property and food resources from unwanted harmful organisms ⎯ pests.