Bug FAQMerchant Grain Beetle
Oryzaephilus mercator · Order: Coleoptera · Family: Silvanidae
Also called: merchant beetle
Source: Wikipedia
The merchant grain beetle is a tiny, flattened beetle about 2.5 mm long. It lives worldwide in stored grain, grain products, fruit, chocolate, drugs and tobacco, feeding on broken grain kernels and other vegetable-origin foods. Females lay 500 to 1000 eggs in food, and the whole life cycle takes roughly 27 to 50 days.
Source: Wikipedia
How to recognize it
It can be told apart from the sawtooth grain beetle by its larger eyes and a narrower area behind the eyes.
Source: Wikipedia
Size
Adults are about 2.5 mm long and have a flattened body.
Source: Wikipedia
Is it a pest in the house?
It is one of the most frequently encountered pests in grain and pantry products.
Source: Wikipedia
How to get rid of it
- In homes, keep susceptible foods in sealed containers to keep the beetles out.
- In commercial storage, clean bins after emptying them to stop infestations of new grain.
Source: Wikipedia
Where it lives
It is a common pest found worldwide in grain stores, pantry foods, fruit, chocolate, drugs and tobacco.
Source: Wikipedia
What it eats
It feeds on any vegetable-origin foodstuffs, especially broken grain kernels, though it can also penetrate whole kernels.
Source: Wikipedia
Life cycle
Females lay between 500 and 1000 eggs each year, depositing them inside a food source. From egg to adult takes about 27 to 50 days.
Source: Wikipedia
Where it comes from
It is a worldwide pest.
Source: Wikipedia
Lookalikes
Its biology is almost identical to the sawtooth grain beetle, Oryzaephilus surinamensis. It differs from that species by having larger eyes and a narrower head behind the eyes.
Source: Wikipedia
Where it is found in the US
Recorded in 11 of 51 states and DC. Most records: Alaska, California, Kentucky, Texas, Georgia, New Mexico, New York, South Carolina.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in Canada; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
How can I tell this beetle apart from the sawtooth grain beetle?
Look for larger eyes and a narrower area behind the eyes; the sawtooth grain beetle has a broader, more triangular head.
Source: Wikipedia
How long does it take for a merchant grain beetle to develop?
The complete life cycle from egg to adult lasts about 27 to 50 days.
Source: Wikipedia
What foods does this beetle infest?
It infests grain, grain products, fruit, chocolate, drugs, tobacco and any other vegetable-origin foods, especially broken grain kernels.
Source: Wikipedia
How can I prevent them in my pantry?
Store susceptible foods in sealed containers to exclude the beetles.
Source: Wikipedia
Same family (Silvanidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Oryzaephilus_mercator
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-29 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-29.