Dark mealworm

Classification

Secondary pest; Grain feeder
Order: Coleoptera
Family: Tenebrionidae
Acronym: TOB

Description

• Adults are similar in appearance to the yellow mealworm, but are often lighter brown in colour.
• Adults are long (12 to 18 mm).
• Dark mealworms may be distinguished from the yellow mealworm by the presence of more dense punctures on the head and pronotum than are present on the yellow mealworm.
• Larvae are cylindrical and move readily through the commodity.
• Larvae are initially white, but darken as they mature and reach a length of 25 to 30 mm.

Similar species

• Yellow mealworm (Tenebrio molitor)

Commodities affected

• Prefers to feed on grain and milled products that are damp and decaying and have been left undisturbed for some time
• Will also feed on sound food items such as meal, flour, bran, grain, coarse cereals, crackers, meat scraps, feathers, dead insects

Signs of infestation

• Larvae and adults are large and readily visible.
• Odours from out-of-condition grain are often noticed before presence of insects, but insects also produce disagreeable odours.

Damage

• Damage is generalized and not recognizable as being caused by this species

How to control

• Control grain insect pests

Geographic range

• Is found worldwide and across Canada

Where found

• Is usually found in association with damp, moldy grain
• Is most often found in dark and damp places, grain bins, sacks of feed, litter of chicken coops and birdhouses, stables, mills, elevators, warehouses, feed mills
• Is often found in association with the yellow mealworm (Tenebrio molitor)

Life history

• Adult females lay 400 to 500 eggs.
• Dark mealworms will readily feed on other insects.