Larger grain borer Prostephanus truncatus (Horn)

[عبد الرحمن الجارحي]

Classification
Primary pest; Grain feeder
Order: Coleoptera
Family: Bostrichidae
Acronym: PTR

Description
Adults are black or brown and cylindrical in shape, heads face down.
Adults are slightly larger (3 to 4 mm) than the lesser grain borer.
Posterior end of the elytra slope back with two strong lateral ridges with sharp edged corners.
Larvae are grub-like with poorly formed legs and are less mobile as they mature.
Similar species
Lesser grain borer (Rhyzopertha dominica)
Ghoon beetles (Dinoderus species) – not found in Canada
Commodities affected
Primarily affects maize
Also affects dried root crops, bamboo, rattan, cassava, wheat, sorghum, dried sweet potato
Will bore into, but does not feed on, cowpea, cocoa, haricot, coffee, rice
Signs of infestation
Characteristic damage is extensive tunneling.
Readily visible holes are bored in seeds.
Copious amounts of flour are produced.
Damage
Damage is distinctive and heavy.
Adults burrow extensively leaving tunnels and irregular shaped holes.
Feeding produces large quantities of flour.
Larval feeding and burrowing contributes further to adult damage.
How to control
Control grain insect pests
Geographic range
Is distributed throughout tropics but not established in Canada
Where found
Is very tolerant of hot conditions and dry grain
Can establish where maize (corn) is stored on the cob and infestation can occur prior to harvest
Life history
Females lay eggs singly or in batches in or near food.
Newly hatched larvae bore into grains or feed on damaged grain and flour produced by adult feeding.
Larvae can successfully develop within a single seed.

[عبد الرحمن الجارحي]