About Stored Product Insects

About Stored Product Insects

Stored product insects (SPIs) refer to a group of pests that infest and damage stored foods and grains, both in homes and commercial settings. These pests can lead to significant economic losses through the contamination of food products, making them unfit for consumption. Common SPIs include various species of beetles, moths, weevils, and mites.

Common Stored Product Insects

  1. Grain Weevils (e.g., Sitophilus granarius): These weevils target stored grains. The female weevil bores a hole into a grain kernel to lay an egg, and the larva feeds inside the kernel, destroying it.
  2. Flour Beetles (e.g., Tribolium spp.): Red and confused flour beetles are common in flour and grain products. They feed on broken kernels and flour dust but can contaminate whole grains through their waste products.
  3. Indian Meal Moths (Plodia interpunctella): The larvae of these moths infest a wide range of dried foods, including grains, nuts, chocolates, and candies. They spin silken webs in the infested product, causing clumping and spoilage.
  4. Sawtoothed Grain Beetles (Oryzaephilus surinamensis): These beetles infest a variety of stored products, including cereals, dried fruit, nuts, and sugar. They are known for their ability to enter well-sealed packages.
  5. Rice Weevils (Sitophilus oryzae): Similar to grain weevils, rice weevils infest stored grains. They can fly, unlike grain weevils, and tend to infest a wider range of products.
  6. Angoumois Grain Moths (Sitotroga cerealella): These moths are primarily pests of stored corn, where the larvae feed on the kernels, but can also infest other grains and seeds.

Biology and Lifecycle

  • Reproduction: Many SPIs have a high reproductive rate, with females laying hundreds of eggs during their lifetime. This rapid reproduction can lead to quick infestations.
  • Lifecycle: Most SPIs go through a complete metamorphosis (egg, larva, pupa, adult), with some capable of completing their lifecycle within a month under optimal conditions.
  • Adaptation: SPIs are well-adapted to surviving in the dry conditions of stored products, with some species able to feed on products with very low moisture content.

Impact and Management

  • Economic Loss: SPIs cause significant economic losses by reducing the quantity and quality of stored food products, leading to direct financial losses for producers, processors, and consumers.
  • Health Risks: Beyond economic losses, the presence of SPIs can lead to health issues for consumers, including allergic reactions and the potential for secondary infections from molds in contaminated foods.
  • Management Strategies: Effective management of SPIs includes a combination of sanitation, temperature control, and physical barriers. Regular inspection of stored products, proper storage in sealed containers, and discarding infested items are crucial steps. In commercial settings, fumigation, controlled atmospheres, and insect growth regulators may also be used.


  • Hygiene: Maintaining cleanliness in storage areas to minimize food residues that can attract SPIs.
  • Storage: Using airtight containers for storing grains and other dried food products to prevent SPI access.
  • Temperature Control: Keeping storage areas cool can slow down the reproduction of SPIs and reduce infestation risks.


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