Stored Grain Pests

Defining stored grain pests
Stored grain pests fall into two main insect orders:
  • Coleoptera (beetles)
  • Lepidoptera (moths)

Within each group, some species are considered as primary pests, they attack the whole grain, while others follow the initial damage as secondary pests. Losses can amount to 10% or more of the commodity through spoilage or secondary fungal infection.

Understanding Primary and Secondary Pests
Primary coleopteran pests include grain weevils (Sitophilus granarius, S. zeamais, S. oryzae), the lesser grain borer (Rhyzopertha dominica) and the saw-toothed grain beetle (Oryzaephilus surinamensis)

Secondary beetle pests include the flour beetles (Tribolium castaneum and T.confusum)

The main lepidopteran pests are secondary; they feed regularly on processed foods so are more common in domestic kitchens and larders.

A variety of pests infest stored grain. This may occur in succession – primary then secondary. Eggs are laid in the grain or part-processed food (flour, bran etc.) where the larvae feed through to the pupal stage.

Moth larvae usually fly to a hidden site away from the food source to pupate, adults then mate and eggs are deposited on or in suitable food.

Emerging beetle adults feed on grain or find shelter in the structure of the silo/warehouse prior to invading new food sources.

Risk:

Stored grain pests attack cereals, pulses, oil seeds, spices, copra, tobacco, cocoa, flour and oilseed extractions during storage. They damage the food and make it unfit for consumption. They also attack and damage processed and packaged food.

 

Control Options

Logistical

Cool temperatures (10°C) reduce the rate of reproduction. While low humidity and ventilation reduce insect activity and viability, they also suppress fungal development.

Pheromone traps aid species control, notably moths, and indicate if and when to treat. Egg to adulthood may take weeks or months, so an infestation is not instantly apparent.

Chemical
Treat empty grain stores between batches of grain to prevent infestations. Treat grain with a residual insecticide at the point of entry into the silo.

Admixture means active ingredient is not subject to photo degradation, while microbial activity in the grain is low, favouring long residual protection.

Fumigation (e.g. in ship holds) with methyl bromide was popular (no residual action but effective control)

Recommended products

Insecticide

K-Obiol

Wettable Powder

K-Obiol is a residual pesticide effective against stored...

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African Black Beetle

Beetles & Weevils

Beetles and weevils are classified in the Order Coleoptera....

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American Cockroach

Cockroaches

Cockroaches are common in commercial premises associated...

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Mosquito

Mosquitoes

Mosquitoes not only cause nuisance by their bites but also...

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Occasional pests

silverfish,millipedes,psocids/booklice,clothes...

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Brown Rat

Rodents

Rodents are arguably the most significant global pest for...

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Termite Worker

Termites

Termites are social insects, working and living together in...

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Black garden ant

Ants

Of all insects that infest buildings, ants are the most...

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Poultry Mite

Mites

Bird mite, Red poultry mite, Couchgrass mite, Grain mite.

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Five Spined Bark Beetle

Five Spined Bark Beetle

Adults are often prevalent in stressed or damaged pine...

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Australian Spider Beetle

Spider Beetle

Gregarious and nocturnal, Spider Beetles spend the day in...

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American Cockroach

American Cockroach

Gregarious and nocturnal, they spend the day hiding in...

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German Cockroach

German Cockroach

German cockroaches are faster and smaller than other...

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Oriental Cockroach - Pest Control - Bayer

Oriental Cockroach

It is most commonly found around the ground-floor of...

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Brown-banded Cockroach

adults and nymphs have two brownish, broad bands across the...

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Mosquitoes - Aedes Caspius

Aedes Mosquito

Aedes mosquito, also known as 'Asian tiger mosquito' has...

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Culex Mosquito

Adult mosquitoes have a typical resting posture wherein the...

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Mosquitoes - Anopheles Macu

Anopheles Mosquito

Adult Anopheles can also be identified by their typical...

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Mosquito Larva

Mosquito Larva

Commonly referred to as “wigglers” or “wrigglers” as a...

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Blow Fly

Blow fly

They are slightly larger than common house flies but have...

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Black Carpet Beetle

Black Carpet Beetle

These flying insects are mainly considered a pest because...

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Carpet Beetle

Carpet Beetle

Including varied Carpet beetle, Furniture Carpet beetle,...

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Black Larder Beetle

Dermestid Beetle

Typically associated with materials with high protein...

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Silverfish

Silverfish

Silverfish are nocturnal and secretive insects that are...

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Clothes Moth

Clothes Moth

They are typically 7–8 mm in length when the wings are...

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Spider

Spider

Most spiders are harmless and play an important role in...

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Booklice

Booklice (Psocid)

Detailed information on the pest including classification,...

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Flea

Flea

Adult fleas live exclusively as parasites of warm blooded...

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Rodent - Pest Control - Bayer

Roof Rat

Roof Rats are expert climbers and are usually black to...

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Rat

Bandicoot

Bandicoot are often found outdoors and tend to live in...

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House Mouse

House Mouse

Mice tend to live in grassy or bushy areas, making their...

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Indian Meal Moth

Indian Meal Moth

TheIndian Meal Moth has forewings which are grey in colour...

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Grain Mite

Grain Mite

The Grain Mite feeds on a wide variety of products,...

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Lesser Mealworm (adult) - Pest Management Bayer

Lesser Mealworm

This pest favours humidity and warmth and is most prevalent...

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Grain Weevil

Grain Weevil

Grain weevils do not fly but instead, infestations often...

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Biscuit Beetle

Biscuit Beetle

A pest of cereal products e.g. flour, bread, it is an...

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Flour Beetle

Flour Beetle

The Flour Beetle resides in the smallest of crevices, and...

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Rice Moth - Pest Control - Bayer

Rice Moth

The Rice Moth has a pale, buff-brown colour which is...

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Housefly

House fly

House flies do not discriminate between food and filth....

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Bed Bug

Bed Bugs

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Bird mite

Bird Mite

So small that they are almost invisible to the human eye,...

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White Footed Ant

White Footed Ant

A small, dull, and cloudy-black coloured ant which can...

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Fire Ant

Fire Ant / Red Imported Fire Ant

The Red Imported Fire Ant (RIFA) has a copper brown head...

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Ghost Ant

Ghost Ant

Very small ants, the workers are 2mm long and have a pale,...

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Black House Ant

Black House Ant

They have a preference for sugary liquids and will tend to...

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Meat Ant

Odorous Garden Ant

Typically omnivores, they can eat proteins and will...

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Pharaoh Ant

Pharaoh Ant

This small ant is yellow-brown in colour with...

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Lesser Grain Borer

Lesser Grain Borer

In India, it is a serious pest of grains. Grain borers are...

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Tropical Warehouse Moth - Pest Control - Bayer

Tropical Warehouse Moth

Commonly also referred to as the Almond moth or Dried...

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Tropical Warehouse Moth - Pest Control - Bayer

Tropical Warehouse Moth

Commonly also referred to as the Almond moth or Dried...

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