Tenebrio molitor L.
Secondary pest: fungus feeder and scavenger
- Adults are large (12 to 18 mm), dark brown or black shiny beetles
- Larvae are initially white, but as they mature they turn a characteristic yellow and reach a length of 30 mm at maturity.
- Dark mealworm (Tenebrio obscurus)
- Prefers decaying grain or milled cereals that are moist and going out of condition
- Will also feed on products not out of condition: meal, flour, bran, grain, coarse cereals, bread, crackers, mill sweepings, meat scraps, feathers and dead insects
- Is occasionally found in bags of fertilizer, bales of tobacco, ground black pepper
- Is occasionally found in dwellings
Signs of infestation
- Damp and out-of-condition grain with larvae
- Damage is generalized and not readily identifiable as being caused by this insect pest
How to control
- Is distributed around the world and across Canada
- Prefers damp, old grain that has gone out of condition
- Is an indication of poor sanitation when present
- Is most often found in areas that are dark and damp: grain bins, sacks of feed, mills, elevators, feed plants, warehouses and in the litter of domestic fowl houses
- Adults appear in early summer.
- Females deposit eggs singly or in clusters in the food or on the sides of bins.
- Females lay 300 to 500 eggs.
- Larvae are resistant to dry and cold conditions and can survive up to 3 weeks at temperatures of -15°C, but prefer 25°C and moist conditions.
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