Stored Product Pests


Stored product insects (SPI) are significant pests as they spend the majority of their time, including breeding, hidden in their chosen food type. Inspection and early detection can therefore prove difficult. The group known as SPI in this context include mites. Commodities attacked include cereals, nuts, dried fruit and pulses.

SPI fall into two main categories according to their ability to infest product:

  • Primary: those having the ability to penetrate whole grains. These are further sub-divided into:
    • Internal: those species whose life cycle is completed within the grain or bean the hole left by the exiting adult is characteristic
    • External: those whose life cycle is completed outside the grain
  • Secondary: tend to feed on the fungus present in poorly stored or damaged product


Due to their close relationship with the product, an infestation of stored product insects can often remain undetected in the initial stages. In order to prevent spread of SPI the following steps should be taken:

  • All incoming raw materials should be sampled for the presence of insects
  • Strict stock rotation must be implemented
  • Thorough cleaning is required to prevent build up of product within plant and machinery
  • Monitoring procedures should be in place to identify early signs of infestation
  • Staff must be aware of the high-risk areas and products on site
  • Accurate identification is essential in order to pinpoint the likely source of the infestation