How to Identify the Indian Meal Moth and the Confused Flour Beetle

Insects can impact commodities in storage – from commercial operations to on-farm stored grain. They can impact grain and eat away at profits.

Let’s take a look at the specific traits, habits, and signs of infestation that will help you identify a couple of common stored grain pests, the Indian Meal Moth and the Confused Flour Beetle.

Identifying the Indian Meal Moth

Also known by their Latin name, Plodia interpunctella, Indian meal moths are small and brownish in color, about 3/8” long with a 1/2” - 3/4” wing span. Their distinctive rusty brown or bronze wing tips make the adults identifiable, while the larvae are off-white with brown heads, about 2/3” long.

The life cycle of an average Indian meal moth lasts for a minimum of 42 days. Interestingly, adult moths are not the stored grain damaging culprits – they do not feed, and they typically die within a week after laying eggs.

Larvae are generally the top feeders, found 4 to 6 inches beneath the surface of stored grain. They’re also found in many types of pantry foods as well as processing and storage facilities. Larvae produce dense webbing that binds to food fragments and can be seen climbing up walls inside bins in the event of an infestation.

Our recommendation for control is to prevent these insects before they become a problem.

• Clean and spray grain bins with Gravista^_® Insecticide prior to grain storage.
• For treatments of six months or longer, inspect and treat incoming grain with Gravista^_® Insecticide and monitor grain throughout your storage period.
• To bring a boost to short-term grain storage of six months or less, and for rescue treatments, treat with Centynal™ Synergized Insecticide.
• For on-farm Indian meal moth control, apply Gravista^_®-D Insecticide to grain being loaded into storage.

Identifying the Confused Flour Beetle

Also known by their Latin name, Tribolium confusum, confused flour beetles have reddish-brown bodies that span to approximately 1/8” long. They have antennae that begin narrow where they connect to the head and then gradually expand toward end. Confused flour beetles do not fly, so identifying them in stored grain requires close inspection.

Confused flour beetles live for a minimum of 42 days on average, but they’ve been known to live up to 18 months, making them problematic for long-term storage. They primarily feed on grain dust, broken kernels and the milled grains in flour and cereal.

Signs of infestation for the confused flour beetle include a foul odor and taste in products they infest. Presence of adult insects is also a surefire sign – check for skins that have shed and fecal matter.

Our recommendation for control is to prevent these insects before they become a problem.

• Clean and spray grain bins with Gravista^_® Insecticide prior to grain storage.
• For treatments of six months or longer, inspect and treat incoming grain with Gravista^_® Insecticide and monitor grain throughout your storage period.
• To bring a boost to short-term grain storage of six months or less, and for rescue treatments, treat with Centynal™ Synergized Insecticide.
• For on-farm confused flour beetle control, apply Gravista^_®-D Insecticide to grain being loaded into storage.

The Bug Free Grains team shares insect identification tips on our social channels, so be on the lookout for more information regarding the Indian meal moth and the confused flour beetle. In the meantime, visit bugfreegrains.com for answers to your stored grain protection questions.