The Ins and Outs of Wheat Bugs

Quality condition wheat is a more precious commodity than ever in today’s market. As harvest of winter wheat wraps up and producers look forward to spring wheat harvest, it’s time to assess storage conditions to protect wheat against profit-robbing insects.

Read on to learn about the types of insects that impact stored wheat, along with the best methods for insect prevention and wheat protection.

Stored Wheat Bugs

Stored grain insects can be split up into two categories, internal feeders and external feeders. Internal feeders eat grain from the inside out, while external feeders rely on grain residue such as dust and other grain debris for sustenance.

Knowing which bug is impacting your stored wheat is the first step in the battle for prevention and protection. Let’s take a look at a few of the insects that are particularly damaging for stored wheat:

  • Granary Weevils: As an internal feeder, the adult granary weevil utilizes a distinct snout to burrow into wheat, creating a “shot hole” appearance. They lay eggs and then cover them with a gelatinous fluid, making detection difficult. Infestations are localized to storage sites and infested grain transportation systems, underscoring the need to treat trucks and equipment for insects.
  • Lesser Grain Borers: These internal feeders are strong flyers, creating “shot holes” in the internal kernel of grain, much like weevils. With the ability to lay up to 500 eggs during their life cycle of about 2 months, adult lesser grain borers deposit eggs on to healthy wheat. The larvae burrow into the kernel and feed on the germ. Both adults and larvae feed on the kernel.
  • Saw-Toothed Grain Beetle: Named for the distinct saw-toothed projections on the sides of the thorax, internal feeding saw-toothed grain beetles infest wheat and congregate in areas together to generate hot spots. The adult lifespan ranges from 6-10 months, and populations can build up quickly.
  • Indian Meal Moth: These external feeders are small, with a distinct reddish-brown copper luster on the forewing. Usually spotted flying near storage sites, their larvae can also climb up walls inside bins, and leave dense webbing on wheat fragments.

Protection and Prevention

The most effective way to protect wheat and prevent insect infestations is to implement a strong integrated pest management (IPM) program, which includes stringent cleaning and sanitation of storage sites before harvest, on-grain preventative treatment, and frequent monitoring and aeration to treat any problems that may arise.

Based on your storage strategy, we recommend using a start-to-finish insect control solution, like Centynal Synergized or Gravista™ Insecticide.

  • Centynal™ Synergized Insecticide brings a boost to short-term grain storage and rescue treatments. By combining both an adulticide and a synergist, Centynal™ Synergized Insecticide provides effective knockdown and will help control even the toughest stored product insects.
  • Gravista™ Insecticide features 3-in-1 insect control with an adulticide, an insect growth regulator (IGR) and a synergist, the no tank-mixing solution to kill labeled insects and break their life cycles.

For more information about our products and more tips on proper stored wheat protection, visit


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