How to Identify Weevils

As notorious as they are damaging, weevils are known as the most destructive pest when it comes to stored grains. In fact, wide swaths of stored grain insects are sometimes incorrectly referred to as “weevils.”

Although prevention is your best bet against weevils or any other stored grain insect, it’s valuable to know how to identify both weevils and their damage. Because they have the capability to completely destroy stored grain, in-depth knowledge of how to prevent and control weevils is critical to protecting your post-harvest stored grains.

Weevil Infestation Signs

  • The biggest indicator of a weevil infestation is a “shot hole” appearance in kernels.
  • Regular temperature checks of your grain are incredibly important, as heat at the grain surface is also a common indicator of a weevil problem.
  • Because weevil larvae develop inside kernels, the presence of adult weevils in your grain is a sure-fire sign of infestation.

Identifying the Rice Weevil
Rice weevils have the ability to fly, making them readily identifiable by their fully developed wings. They are often reddish brown or black in color, with light reddish yellow spots. Rice weevils in the larval stage are soft-bodied and white, feeding on the inside of grain kernels.

Identifying the Granary Weevil
The granary weevil’s primary species distinction is its lack of ability to fly. Grain weevils also have a long snout, reddish brown or black bodies, and wing covers despite their inability to fly. As larvae, granary weevils are legless, small white grubs that feed on the inside of kernels, much like the rice weevil.

Prevention and Control

  • Empty Bins: In order to prevent weevil infestations, regularly clean and treat all storage facilities and bins. For empty bin treatments, Central Life Sciences has the solutions for weevil infestation prevention. We recommend applying a tank-mix of Diacon® IGR PLUS and PBO-8® Synergist thoroughly inside bins and to grain handling equipment.
  • Control Methods: Based on your storage strategy, we recommend turning and treating your grain with Diacon® IGR PLUS and PBO-8® Synergist, or with a rescue treatment of Centynal™ EC Insecticide and PBO-8® Synergist.
  • S.L.A.M: Sanitation, Loading, Aeration and Monitoring are a must for prevention of weevils and all other stored grain insects.

Weevils are among the most difficult stored grain insects to control, but by implementing a comprehensive integrated pest management (IPM) program, can help keep your investment free of weevils and other nuisance pests. Central Life Sciences has the product solutions to help keep your grain bug-free.


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