Common Stored Product Insect Species

Lesser Grain Borer

(Rhyzopertha dominica)

Appearance

• Adult is 2–3 mm in length. 
• Ranges from red-brown to black-brown in colour.

Lifecycle

• Female produces 200–500 eggs. 
• At ideal temperature of 34°C and 70% Relative Humidity (RH), pupation takes up to 3 days.
• At ideal temperature (34°C and 70% RH), life cycle last around 3—4 weeks.

Habits

• Eggs are laid in crevices or on the rough surfaces of a seed. 
• Larva will bore inside the grain to continue growing. 
• Larva develops faster on whole grain compared to flour. 
• Adult mate as soon as they emerge. 
• Commonly found in warehouse and store.

Drugstore Beetle/Biscuit Beetle

(Stegobium paniceum)

Appearance

• Adult is 2–3.5 mm in length. 
• Light brown in colour and oval in shape. 
• Antennas end with 3–segmented club.

Lifecycle

• Female produces 20–100 eggs. 
• Eggs take around 60–210 days to develop into adults, with 1–4 generations per year depending on the temperature.
• Adult lives for about 13–65 days

Habits

• Adults are active fliers, especially during afternoon to evening time.
• Commonly found infesting processed goods such as chocolate, confectionery and biscuits. Also often found on dried food product such as dried herbs and spices.

Cigarette Beetle

(Lasioderma serricorne)

Appearance

• Adult is 2–3 mm in length. 
• Light brown to reddish brown in colour. 
• Antennas are about half of its body length and are shaped serrated (saw-like).

Lifecycle

• Female produces up to 30–42 eggs. 
• Eggs take 30–90 days to develop, with 3–6 overlapping generations per year. 
• Adult lives 23–28 days.

Habits

• Larva produces a cell of food fragments and waste materials to pupate.
• Adults are active fliers, especially during afternoon to evening time.
• Adult do not feed while the larva is the one doing the damage.
• Feeds off tobacco, dry stored food products, spices, seeds, grains and dried plant material.

Rusty Grain Beetle

(Cryptolestes ferrugineus)

Appearance

• Adult is 1.5 – 2.5 mm in length. 
• Red-brown in colour with flat body.

Lifecycle

• Female produces up to 200 eggs. 
• In ideal temperature conditions, the life cycle is about 23 days.

Habits

• Adults walk with a characteristic swaying movement. 
• Adults are winged but rarely fly. 
• Feeds on cereals, dates, dried fruits and other materials.

Saw Toothed Grain Beetle

(Oryzaephilus surinamensis)

Appearance

• Adult is about 2.5–3 mm in length. 
• 6 sawlike teeth on each side of prothorax

Life Cycle

• Female produces 45–285 eggs. 
• Life cycle takes about 30–50 days.

Feeding Habits

• Larvae feed within mass produce. 
• Adults are winged but do not fly. 
• Often wander from food into cracks, crevices and roof spaces to hide.

Khapra Beetle

(Trogoderma granarium)

Appearance

• Adult is 2 – 3 mm in length. 
• Dark brown in colour with light brown pattern on wing covers. 
• Oval in shape.

Lifecycle

• Female can lay up to 35 eggs.
• It takes about a month to complete life cycle.

Habits

• Larvae make the most damage on stored products by shedding cast skin and feeding on materials. 
• It can survive up to 9 months without food. 
• Commonly found infesting grains, cereals and pulses.

Copra beetle/Red Legged Ham Beetle

(Necrobia rufipes)

Appearance

• Adult is around 3.5–7 mm in length. 
• Shiny green to bluish green in colour with red legs.

Lifecycle

• Female lays up to 30 eggs per day in cracks or crevices of cured fish. 
• Adult lives up to 14 months.

Habits

• Commonly feeds on dried copra and other insects that are attracted to mouldy food. 
• Infest areas such as palm kernels, oilseeds, spices, dried fish and other meat products. 
• Adults are slow fliers and will bite human when disturbed.

Granary Weevil

(Sitophilus granarius)

Appearance

• Adult is 3–4.8 mm in length. 
• Reddish brown to black in colour.

Lifecycle

• Female lays eggs in grain kernel cavity. 
• At ideal temperature conditions (30°C), it takes 30 days to complete life cycle.

Habits

• Newly emerged adult leaves large ragged holes. 
• Feeds on grains and hard cereal products such as macaroni and spaghetti.

Rice Weevil

(Sitophilus oryzae)

Appearance

• Adult is 2.5–3.5 mm in length. 
• Brown to black in colour with reddish spots on the back of the abdomen. 
• Has a long slender snout.

Lifecycle

• Female lays 300–400 eggs. 
• It takes as short as 32 days to complete life cycle. 
• Adult lives up to 3–6 months.

Habits

• Female drills a tiny hole in the grain kernel to lay egg in the cavity. 
• Grows, feeds and pupates within a grain kernel.

Flour Beetle

(Tribolium castaneum)

Appearance

• Adult is 3–4 mm in length. 
• Reddish brown in colour.

Lifecycle

• Under optimal conditions, it takes 20 days to develop from egg to adult.

Habits

• Larva and adult feed on wide range of durable commodities such as groundnuts, nuts, spices, coffee, cereals, dried fruits and animal feed. 
• Disperses by flying and does not depend on humans' movement of food products.