Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Coleoptera

Infraorder: Cucujiformia

Family: Tenebrionidae

Genus: Tribolium

Species: T. castaneum

The original distribution of Tribolium is suspected to be in the region of India, southwestern Asia and the eastern Mediterranean. The genus has since spread worldwide via human trade.

Host Range
The red flour beetle has a very broad host range. It is a major pest of the following crops among others: maize, groundnut, oats, Brazil nut, barley, walnuts, lentil, rice, beans, peas, almond, rye, sorghum and wheat. The red flour beetle also attacks a wide range of dried stored products.

The adult red flower beetle is approximately 3-4 mm long with a flattish curved-sided body which is reddish-brown in colour. The head and upper part of the thorax are covered with minute punctures and the wing cases (elytra ) are ridged along their length. The antennae are enlarged at the tip (capitate) with the last three segments wider than preceding segments. The eyes are reddish-black in colour. Eggs are approximately 0.5 mm long, cylindrical and white or colourless. They are sticky which causes them to become covered in flour and stick to containers. The larvae are yellowish-white, slender, and cylindrical and covered with fine hairs. The head is pale-brown and the last segment of the abdomen has two upturned dark, pointed structures. The pupa does not have a cocoon and is yellowish-white, becoming brown later.

It is possible to confuse the red flour beetle (Tribolium castaneum) with the ‘confused flour beetle’ (Tribolium confusum). It is very difficult to distinguish between the larvae of both species. Adults of both species are similar in size and colouration but they can be distinguished by the following features among others: the eyes of the red flour beetle are larger and closer together than those of the confused flour beetle; the red flour beetle has a curved-sided thorax while the confused flour beetle has a straight-sided thorax ; the last three antennal segments of the red flour beetle are much broader than the previous segments while the antennal segments of the confused flour beetle gradually broaden. Adults of both species have well developed wings but only the red flour beetle has been observed to fly though it is not a strong flyer.

The red and confused flour beetles may be present in large numbers in infested grain, but are unable to attack sound or undamaged grain (Walter). The adults are attracted to light, but will go towards cover when disturbed. Typically, these beetles can be found not only inside infested grain products, but in cracks and crevices where grain may have spilled. They are attracted to grain with high moisture content and can cause a grey tint to the grain they are infesting. The beetles give off a displeasing odor, and their presence encourages mold growth in grain.

Eggs are deposited directly in flour, other food material, or attached to the surface of the container. They are white or colorless and covered by a sticky material to which flour can adhere. Eggs hatch in 3-5 days at 32-35˚C (89.6-95˚F). Larvae burrow into kernels of grain but may leave their burrows in search of more favorable food. There at 5-11 larval instars (7-8 is usual), the variation a result of environment, food, temperature, humidity, or the individual insect. Larvae are fairly active but generally hide within the food, away from light. Pupae are naked, without protection of any form. Development time from egg to adult varies with conditions, however, the average is 26 days at 32-35˚C (89.6-95˚F) and >70% Rh. The minimum, maximum, and optimum temperatures for development of the confused flour beetle are all about 2.5˚C lower than the red flour beetle. Limits of development are imposed mostly by larval mortality, esp. among early instars. The minimum temperature for development is between 20-22˚C (69-71.6˚F), the maximum 37.5-40˚C (99.5-104˚F) when the relative humidity is either low (10-30%) or high (90%). Flour beetles can survive in grain with moisture contents as low as 8%. Average fecundity is 400-500 eggs per female, with peak oviposition occurring during the first week. Adults may live longer than 3 years, and females may lay eggs for more than a year.

• Egg Stage: The life cycle begins with the female red flour beetle laying small, white eggs on or near the food source. Female beetles can lay hundreds of eggs during their lifespan. The eggs are tiny and difficult to see with the naked eye.
• Larval Stage: Once the eggs hatch, larvae emerge. Red flour beetle larvae are small, worm-like, and have a white or cream color. Larvae actively feed on the stored food, causing damage to grains and processed products. The larval stage consists of multiple instars (molting stages) as they grow in size.
• Pupal Stage: After completing the larval stage, the larvae enter the pupal stage. The pupa is non-feeding and is a transitional stage during which the larva undergoes metamorphosis into an adult. Pupae are typically found in the vicinity of the food source.
• Adult Stage: The final stage is the emergence of the adult red flour beetle from the pupa. Adult beetles are small, approximately 2 to 4 millimeters in length, and have a reddish-brown color. They have well-developed wings, but they are not strong fliers.

1. It Is a generalist feeder and damage is not readily attributable to this pest
2. Releases a noxious secretion, when disturbed, resulting in a pungent odor in the infested
3. commodity, rendering milled products unfit for consumption
4. May cause food to acquire a pinkish tinge when a large number of insects are present
5. ItIs typically found in grain that has become heated

1. Heated grain
2. Pinkish coloration to food products at very high population densities

1. Seeds and grains
2. Internal feeding
3. Contamination with faeces
4. Promoting mould 

The red flour beetle (Tribolium castaneum) is considered an important pest due to its significant impact on stored food products.

The first step in managing an infestation is to find and remove the source of the infestation (Koehler 2003). Flour beetles can feed and survive on even the smallest bits of grain, so cleaning is a crucial part of controlling these pests. When attempting to locate the source, be sure to consider all likely food items including, dry pet food, dried flowers, nuts, birdseed, and all grain products. Be sure to look for “leaky packages.” Small bits of meal or grain spilling from a package are often a signal that an infestation is present (Arbogast et al. 2000). Be sure to locate all infested material and discard it by placing the material into a sealed bag or container and throwing it into an outside garbage container. You may also place the infested material into a freezer for four to five days. Keep in mind that these beetles may infest areas other than the pantry. Be sure to inspect spices, pet food, and flower arrangements. Also keep in mind that some stuffing in furniture or stuffed animals may have natural products that these beetles could feed on. Also be aware of areas in which any of these products may have spilled, like under the refrigerator or stove. These beetles are able to locate very small bits of food. Once all of the infested material has been removed, be sure to vacuum and clean up the area around the infestation. If you have shelf paper, it would be wise to remove it, thoroughly clean under it with soap and hot water, and replace it with new paper. Be sure to pay close attention to the cracks and crevices of any cabinets. To prevent re-infestation, all grain products should be stored in containers with tight fitting lids, or stored in the freezer. Also consider where the infestation came from. It is likely that you could have a re-infestation by purchasing infested grain products from the same business. When shopping, look for those “leaky packages”. If you suspect a beetle infestation, don’t buy the product.

The severity of a red flour beetle infestation can be reduced by good store hygiene: cleaning the store between harvests, removing and burning infested residues, immersing grain sacks in boiling water and removing wood from stores or fumigating the store to eliminate residual infestations and the selection of only uninfested material for storage.

The red flour beetle is affected by a variety of parasites, parasitoids and predators that affect it at all stages. The editors could not find information on the effectiveness of these agents as grain moth control agents. The fungus Beauveria bassiana has proven efficacy for many insect pests of stored grain and grain products but is not considered a commercially viable stand-alone option for controlling the red flour beetle.

Occasionally, mice or other rodents can cause a persistent beetle infestation. Hoarded seed and grain in abandoned rodent nests can support a small population of pests. Old rodent bait that contains grain also can harbor insects. When controlling rodents, prevent insect problems by placing the bait where it can be retrieved and discarded after the rodents are controlled.

Heat or cold treatments can eliminate pests in some food items such as pet food, bulk grains and beans, and home-grown dried beans or peas. Put the product in the oven at 130 degrees F for 1 hour, or in the freezer for 7 to 14 days. To prevent an infestation, store foods that may attract pantry pests in the refrigerator or freezer.

On rare occasions, insecticides may be needed to control difficult infestations. Insecticides can reach inaccessible areas that cannot be easily cleaned; they can also help reduce heavy pest infestations more quickly. Insecticide sprays may be applied to crevices and void areas around cupboards, drawers, and pantries. Before spraying, remove all food products, utensils, and containers from the treatment area. Allow the spray to dry before placing clean shelf paper on the shelves and returning food, utensils, or containers to the pantry.

Insecticide products that are labeled for use in food- storage areas generally contain ingredients that are short-lived and relatively safe to use in the home. Active ingredients of these products include pyrethrins, resmethrin, allethrin, and tetramethrin. For areas where long-term residual control is de- sired, look for products containing synthetic pyrethroids, such as permethrin, esfenvalerate, cyfluthrin, or bifenthrin. Aerosol fog products can temporarily suppress infestations of flying insects, but these fogs will not kill pantry pests in food containers or protected locations.

Before using an insecticide, always make sure that the label says that the product may be used indoors and in kitchens. Never spray food, dishes, utensils, or cooking items with pesticides.

No information found

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