Stored Product Pests and Stored Product Pests and Their ControlTheir Control

Dr. Richard M. Houseman

Department of Entomology

University of Missouri

Stored Product Pests

• Two main orders– Order Coleoptera

• Beetles

• 300,000 species world-wide

• 40,000 species in U.S.

– Order Lepidoptera• Butterflies

• 112,000 species world-wide

• 11,000 species in U.S.

• Damage is done mostly by the immature stages.

Missouri Stored Product Pests

• 12 Important Pests– 10 beetles– 2 moths

• Can be divided into two main feeding groups– Pests of whole grains

• Consume the grain embryos (protein)

– Pests of processed grains

Whole Grains

• Rice weevil (Sitophilus oryzae)

• Granary weevil (Sitophilus granarius)

– More common in granaries and mills

– Pierce grains with beak and lay eggs inside

– Many cereal grains and seeds infested

• Several are found in storerooms, pantries, garages

Whole Grains

• Lesser grain borer (Rhyzopertha dominica)

– Infests grains in storage or in transport

– Strong jaws to open grain and then lay eggs

– Rarely a problem in homes or stores

• Unless materials arrive infested

Whole Grains

• Cowpea weevil (Callosobruchus maculatus)

– Not true weevils• No snout

– Only infest legumes• Peas, cowpeas, beans

– Lay eggs on outside of seeds and the larvae penetrate

Whole Grains

• Angoumois grain moth (Sitotroga cerealella)

– Mostly a problem in grain storage

– Less common in homes

– Commonly found in whole kernel corn

– Will fly inside buildings

Dr. RM Houseman

Processed Grains

• Sawtoothed grain beetle (Oryzaephilus surinamensis)

– Six teeth along edges of pronotum

– Eggs deposited into foodstuffs

– Larvae look like lumps and stay in foodstuff

– Adults will wander around

Processed Grains

• Warehouse beetle (Trogoderma spp.)

– Infest grain-based products

• Cereal

• Spices

• Rodent baits

• Dog food

– Found in warehouses, storage rooms, homes

Processed Grains

• Cigarette beetle (Lasioderma serricorne)

– Covered with tiny hairs that give it a sheen

– Very small larvae • Difficult to locate

• Covered with product

– Infest many things• Spices, pet food,

prescription drugs, tobacco, cosmetics,

Processed Grains

• Drugstore beetle (Stegobium paniceum)

– Similar to cigarette beetle

– Dull, dark appearance

– Infest many things• Spices, pet food,

prescription drugs, tobacco, cosmetics,

Processed Grains

• Confused flour beetle (Tribolium confusum)

• Red flour beetle (Tribolium castaneum)

– Dry milled, cereal products

– Flour mills, retail stores, homes

– Nearly impossible to avoid this pest in mills

• Flour, cornmeal, cake mixes may harbor them

Processed Grains• Indianmeal moth

(Plodia interpunctella)

– Most common pantry pest in Missouri

– Storage areas, stores, homes

– Life cycle of 2 months– Larvae spin silk

• Can cover the product

– Will leave product and wander for distances

• May even hang from ceilings

Stored Product Pest Control

• Four basic steps– Locate infested product– Discard infested products

• Cheaper to replace it than to freeze/heat/treat

– Clean infested area thoroughly– Prevent new infestations

• Thick plastic, metal, air-tight containers