Stored Product Pests (SPIs)

The term stored product insects or SPIs covers a whole host of small insects that can affect stored foodstuffs in locations from home cupboards to commercial food factories. The inclusion of these pests in stored products such as grain, rice, pulses, and processed food often renders them unfit for sale or consumption.

Although small, the global economic impact of these stored product insects is enormous, affecting all stages of food production from the primary producer to the end consumer. They can cause the recall of products, generating costs and causing additional losses from the disposal of affected products.

Stored Product Pests - Landguard Pest Control

Amazingly insect pests are estimated to destroy around 20% of the world’s grain crop production each year, costing billions and earning the title of the ‘world’s most expensive pest’.

Common Species of SPI

A few of the native and non-native species found in the UK include:

  • Rice weevil
  • Biscuit beetle
  • Indian meal moth
  • Grain weevil
  • Confused flour beetle
  • Saw toothed grain beetle
  • Larder beetle
  • Mill moth

Types of SPI in the UK

In the UK we have two common types:

  •  Beetle
  •  Moth

How to identify if you’ve got an SPI issue…

The most typical indication of a stored product infestation is the appearance of the adult insect – either an unusual number of moths flying or beetles appearing in and around kitchens and storerooms.

Other signs include damaged packaging, dusty, broken down products, and ‘Frass’ – the solid excreta of insects and other related matter created by the feeding process.

Look out for the inclusion of all other life stages in and around food preparation and storage areas. Due to minuscule sizes, the egg, larvae, and pupae can be challenging to spot.

There is often a mistaken belief that getting rid of the adult insect will solve the problem. However, the earlier life cycle stages may still exist throughout the stored product(s).

Other signs include – 

  • Moth larvae webbing, weaved throughout affected materials.
  • A distinct ‘taint’ discolouration found in stored products.
  • Damp, mould, and grain germination in infested stores and silos.
  • Track marks in dust or flour left by the adult insect.
Stored Product Pests - Landguard Pest Control
Product Storage Insects - Landguard Pest Control

How to prevent SPIs

  • Prevention is very difficult; SPIs usually enter the house unnoticed in and around infested products and packaging.
  • In advance of (or during) an infestation, you can limit its spread through good storage and hygiene practices.
  • Remove food products from their original packaging and place them in tightly sealed containers. This will prevent any access and protect the product.
  • Vacuum regularly to remove food debris inside cupboards and around storage areas, thus removing the food source that can propagate or sustain an infestation.

What if you find an SPI inside a product you’ve recently bought?

If you find an SPI when opening a new product, you should return it to the store you purchased it from and explain the situation. It will hopefully result in you regaining your lost expenditure and enable the store to investigate and implement their own control measures if necessary. They may also need to inform suppliers to establish where the insects entered the food chain.

Stored Product Pests

What do you do if you have a SPI infestation in your property?

Give us a call. We have the knowledge and experience action effective and targeted treatments based on stored product insects’ habits and life cycles. We’ll also advise you on how to help prevent a reoccurrence.


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