Khapra beetle

Khapra beetle

Trogoderma granarium

Common name:

Khapra beetle

Scientific name:

Trogoderma granarium

Alternative common names:


Description:

Khapra beetle is one of the world’s most destructive pests of grain products and seeds. It is considered one of the 100 worst invasive species in the world. Infestations are difficult to control because of the insect’s ability to survive without food for long periods, its preference for dry conditions and low-moisture food, and its resistance to many insecticides.

Additional Information


Where does this species come from?

South Asia

What is its invasive status in South Africa?

NEMBA 2020 Category 1b

Where in South Africa is it a problem?

Eradicated. It was once found but never established.

How does it spread?

These beetles are primarily spread by the transportation of infested materials such as bagged cereals, grains or seeds.

Why is it a problem?

They destroy valuable commodities by feeding on grains and seeds, often leaving only the husk behind. They are resistant to most insecticides.

What does it look like?

Description: The adults are oval-oblong and are covered in dense hairs. Males are brown to black and females lighter. The antennae are yellowish-brown with a distinct club; its legs are yellowish-brown. Males are 1.4-2.3mm long, 0.75-1.1mm wide; adult females are 2.1-3.4mm long, 1.7-1.9 mm wide. The early stage larvae are yellowish white with a brown head and mature larvae are golden to reddish brown. All stages are very hairy.

Habitat: They are found in grain stores, food stores, malt houses, seed processing plants fodder production plants, dried milk factories, merchant stores, stores of packing materials (used sacks, bags, crates).

Breeding: The khapra beetle produces between one and nine generations per year depending on factors such as the host species, temperature, light and moisture. High humidity slows down population increase. Adults live for 12-25 days and females lay between 50-100 eggs. The eggs, which are loosely scattered in host material, hatch in 3-14 days. Larval development usually takes 4-6 weeks during which time they moult 4-15 times. The pupal stage lasts 2-5 days and quiescent adult stage 1-2 days. The larval stage however, can last from a month to a year, if it enters diapause (a dormant phase).

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