Effective Biological Methods for Wheat Weevils Control

The wheat weevil (Sitophilus granarius), who notoriety ranks among the first pest of stored grains, contributes greatly to the destruction of wheat stocks worldwide. The granary weevil, with its hardened dark shell and thin snout, bores into grains to lay eggs, causing internal damage. 

Wheat grains damaged by a wheat weevil.

Grain weevil treatment is an integration of many chemical, cultural and organic measures. The use of chemical treatments like safe insecticides or wheat weevil killer is the first purpose. The cultural practices as second, which are aimed at keeping clean and dry storage conditions to avoid infestation. Biological methods are the ones that use the natural enemy like Beauveria bassiana to target and curtail weevil populations. 

If you are looking for an answer to get rid of wheat weevil, continue reading the blog.

Wheat Weevil Life Cycle

Close-up of two wheat weevils on wheat grains.

Here is a concise bullet-point summary of wheat weevil life cycle:

  • Egg Laying: In breeding, female weevils like weeds drills into grain kernels using their snouts in order to hatch them.  
  • Larval Development: Grain inside is destroyed by the developing larvae and they are also shielded from possible danger. 
  • Pupation: The grub pupates inside the grain and pierces the grain coat with an emergence hole during metamorphosis. 
  • Adult Emergence: At the mature stage, the adults fly out from the grain to mate and the cycle thus continues. 
  • Environmental Factors: Climate factors like heat and humidity affect the durations of weevils.

Sitophilus Granarius Symptoms

Single wheat weevil on rice grains.

  • Visible Holes in Grains: Flour mites bore into kernels, creating a hole in the center of the grains. This results in a small hole that is visible from the outside of the kernels.
  • Hollowed-out Kernels: Often grains, filled with larvae, look visually damaged on the inside, by the larvae who have consumed all the grain material resulting in weight and quality reduction.
  • Presence of Frass: Weevil frass begins to build-up around storage points and this could imply that weevils are actively eating or having been moving around within the stored grains. 
  • Live Weevils and Larvae: Evident presence of adult weevils or larvae in grains stands for active infestation, which frequently requires reacting promptly in order to mitigate damage and further spread. 

Wheat Weevil Treatment Methods

Wheat weevil control infestations require the utilization of both chemical and biological methods, each having pros and cons, either as preventive or curative measures. 

Cultural methods serve as the first barrier of defense by blocking the weevils’ way of life through disruption of the environment. Thoroughly clean warehouses where you found infested grains, and regularly inspect other potential development areas diligently. Apply regular, thorough inspection and cleanliness measures to prevent primary infestations or reinfestations effectively in all storage areas. Ensure adequate ventilation and maintain low temperatures to limit moisture levels, effectively killing weevils’ offspring in storage.

Chiral devices will be used to treat advanced infestations that are not responsive to cultural methodologies alone. In general, apply pesticides specifically labeled as safe for use on stored grains. When choosing biocides, consider threats to humans and animals, residual grain poisoning, and weevils developing further resistance. Using strategic doses and adhering to treatment instructions increases effectiveness while reducing environmental impact.

 MET Zone product for treating wheat weevil infestation.

Effective Biological Methods for Wheat Weevils Controlcontrol includes such approaches as introducing the insects that are natural enemies of weevils or employing microbial agents that are located only in the pest populations. An effective approach would be the implementation of weevil control insecticides like Grub Killer and mycotoxin Metarhizium anisopliae formulations. Wheat weevil killers are made from these materials and are composed of live fungi that are transformed into bio-insecticides. For instance, the Grub Killer, weevil control insecticide, apparently aims at the destruction of the larvae stages of the pests using its mechanism of spraying grains on contact that are already treated.

The spores of Metarhizium anisopliae infect weevils, killing them within days, making them vital for IPM. These biological agents are less aggressive and environmentally friendly alternatives to chemicals in food production. They help create food products with low chemical concentrations in the environment. Using applicational, chemical, and biological methods can control current pest infestations and prevent future outbreaks. This integrated method ensures grain quality, safety, and promotes eco-friendly insect management. For more details, visit the pages of Substrate Nest, Wasp, Proteozen, Parasitic Mud Nest, and Metarhizium anisopliae.


Finally, the supervision of wheat weevils in grain storages consists in the utilization of the whole range of methods. This includes cultural, chemical and biological, to guarantee the efficiency and grain weevil treatment. Cultural practices such as making sure that insects can not get access to contaminated foods by storing them in cool and dry spaces can help us avoid the start of the infestation process. 

Use chemical control operations moderately to avoid ecological damage and prevent pests from developing immunity to drugs. Biological control methods, such as Grub Killer and Metarhizium anisopliae, are more natural and eco-friendly alternatives. Integrating these techniques into a comprehensive pest management plan will maintain high grain quality and safe food supplies. This approach contributes to sustainable agriculture development, ensuring the nation’s long-term economic sustainability and security.

This “integrated” approach not only fulfills immediate pest control needs, but also contributes to wider environmental and health interests of the wider community. 


  1. Batta, Y. A. “Control of rice weevil (Sitophilus oryzae L., Coleoptera: Curculionidae) with various formulations of Metarhizium anisopliae.” Crop Protection 23.2 (2004): 103-108.
  2. Kavallieratos, N. G., et al. “Effect of the combined use of Metarhizium anisopliae (Metschinkoff) Sorokin and diatomaceous earth for the control of three stored-product beetle species.” Crop Protection 25.10 (2006): 1087-1094.

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