Lesser grain borer

Classification

Primary pest; Grain feeder
Order: Coleoptera
Family: Bostrichidae
Acronym: RDO

Description

• Adults are dark reddish brown and 3 mm long with distinctly shaped, loose 3-segmented club.
• Larvae are white and c-shaped. They are immobile at maturity with dark head capsule.

Similar species

• Larger grain borer (Prostephanus truncatus, not found in Canada)

Commodities affected

• Nearly all grains, especially wheat, barley, sorghum and rice
• Seeds, dried fruit, drugs, cork, wood and paper products

Signs of infestation

• Large amounts of flour
• Tunnels and irregularly shaped holes in commodity
• Sweet odour in the grain

Damage

• Damage is distinctive and heavy
• Adults and larvae feed on germ and endosperm reducing kernels to shells of bran
• Adults and larvae also burrow through kernels

How to control

• Control grain insect pests

Geographic range

• Is found worldwide and across Canada, although is not common in all provinces
• Is not well established in Canada due to colder climate

Where found

• Is most common in buildings; may be found in shipping containers

Life history

• Lesser grain borer is one of the most injurious pests known to attack grain.
• Adults are mobile, able to fly and are long-lived.
• Females lay eggs one at a time or in batches of up to 30 eggs.
• Larvae live within the seed and are rarely found in sieve samples.
• Larvae pupate within grain kernel.

Video

• Video of Lesser grain borer