Eliminating Weevils in Flour and Rice

Rice and Flour Weevils are Gross but Easy to Avoid


Photo by Shelley DeDauw

Their little legs wriggled on my spoon. How harmful could they be? Casting my eyes to each side, I watched for approaching family members as I dropped the little bugs in the sink and stirred the flour.

It would be a long battle with weevils in flour and rice. Disgusting little insects, they’re the bane of anyone who buys grains in bulk. They can invade and multiply before the urge to bake strikes again. Weevils in flour, in my pasta … in the corner joints of the cupboards.

I’ve never respected Tupperware this much in my entire life.

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For years I stored open sacks of flour, prying apart the paper triangles then folding them back over as I again stored them in the cupboard. Who knows how they invaded. Contaminated grains from the supermarket? That plate of cookies sent by my kids’ grandmother?

Black flecks happen. When you train children to wash dishes, you deal with a lot of black flecks. I just wipe them from the bowl and make my no-knead artisan bread. But after I scooped the flour, ran off to scold my dogs for barking, grabbed the yeast I had forgotten, and returned, the black flecks sat on top of the flour. And they moved. I paused, yeast still in hand, and leaned close. Little legs wiggled beside those black flecks.


I threw the weevils in, flour and all, to the compost bin and scooped more out of the bag. Weevils crawled through that as well. Nearly 10 cups of flour powdered the other kitchen waste before I dug down past the weevils. And even then, a couple bugs still crawled through.

I always twitch when I see people waste food. Scowling at the flour, I grumbled and tucked the yeast away. Maybe we’d have biscuits instead. With peppered sausage and country gravy. Nobody would ever know.

There are over 6,000 insects with the name “weevil,” many of which aren’t in the same genus. I dealt with the grain weevil, which lays eggs inside kernels of wheat. These bugs can severely damage grain stores and even love pasta and prepared cereals. They burrow through paper and cardboard containers and creep beneath narrow gaps in lids. One female can lay 400 eggs which hatch within a few days.

But though they’re gross, they’re not at all harmful to humans.

I keep telling myself that. I’ll open a new, untainted bag of flour and transfer it to plastic containers with tight-fitting lids. Then my family will help cook, returning the flour to the cabinet without pushing the lid down tight. I open the container with dismay. Not harmful. Protein and fiber. As I scoop off what I can and wash them down the sink, I wonder how visible they will be in my baked goods. If they stick in my teeth, will they look like pepper or will the little legs show? Perhaps I should bake a chocolate cake, just to be safe.

For a while, I had control over them. I’d by 25-lb bags of flour because 25-lb bags are one of the most economical. Knowing my family would neglect to secure lids, I portioned the flour among half-gallon mason jars and sealed them within the oven, one of the food preservation examples acceptable for dry goods. I stored all jars in the canning room except for the one currently in use. And after I scooped out my flour, I twisted the metal ring down tight.

Then someone gave me a 50-lb bag of rice. I had wheat weevils in flour. No problem. The rice didn’t sit long in its factory packaging and I never saw weaknesses in the bag. When I separated the rice into 2-cup portions and vacuum sealed them in Food Saver bags, I congratulated myself on staying ahead of the weevils.

Until I made rice.

I cut open the bag and dumped it into the hopper of the rice cooker. As I added water, I noticed tiny flecks of rice rising to the top. Is it…no, it couldn’t be. Then a grown weevil rose to join its white larvae offspring. Apparently I had rice weevils, which are in the same genus as wheat weevils but a slightly different species.

Shuddering, I listened to the guests conversing in the living room as I poured the water off as quietly as I could. Most of the bugs and larvae flowed off into the sink. Two more times I rinsed the rice, stirring it with my hands to bring any bugs up to the surface. When nothing else floated on the top and I saw no black flecks among the rice, I proceeded to cook it. Before serving, I stirred the rice and looked close. No black flecks. I sighed in relief, pulled my face into a guest-pleasing smile, and called everyone to dinner.

With each incident, I learned more. I wanted to tell my friends how to avoid weevils.

  • Freeze the flour for four days after you bring it home, to kill any bugs or eggs that may be present. If you have the space, store your food in the freezer full-time.
  • Keep flour in containers with tight-fitting lids and use the flour often to keep it fresh.
  • Place a bay leaf in the flour to deter bugs.
  • Bake your grains in the oven at 120 degrees for an hour. This will kill both eggs and live weevils in flour and rice.
  • If you get bugs, remove food from the cupboards and wash the cupboards with soap and water. Finish with a little eucalyptus oil to repel new visitors. If you can afford to, throw away infested food or give it to your chickens.
  • Since these critters live in your food, avoid pesticides. Pyrethrins and diatomaceous earth are non-toxic options but never apply these directly to your food.
  • Remember that we have probably all eaten weevils in flour or baked goods. Eggs, a piece of a leg, in our cookies and breads. It doesn’t hurt us and it’s pretty unavoidable.

But to educate my friends, I’d have to confess that I had weevils. They’d never eat my banana bread ever again.

Or perhaps they have weevils as well and are ashamed to admit it. Listen, dear friends. Weevils are nothing to be ashamed of. They’re disgusting and highly contagious between pantries, but having these bugs doesn’t mean you have an unclean house. It means you have grains. And that you need to store your dry goods correctly.

I’m happy to say I’m now 6 months weevil-free…

Nope. Apparently not. Because, though my flours, rice, and pasta are now vacuum sealed or packed in mason jars, tidbits of grain still lurked.

I was making cheesecake. Thick, white, flour-free cheesecake. And I had a feeling I should have used the stand mixer, but instead I grabbed the handheld unit that sat in the cupboard beside the baking ingredients. I never thought about the tidbits of dough and flour that fly up into the gears; it’s just dust and a drop or two of liquid. Nothing to worry about. But as I inserted the beaters into my cream cheese and eggs then turned the mixer on, centrifugal force sprayed black weevils into my bowl. The beaters immediately folded them into the cheese. My forehead tapped against the cupboards. Unless I could chop some fresh blueberries into the cheesecake, those black flecks wouldn’t go unnoticed. Carefully folding through the batter, I picked out little bugs. The process took twice as long as the entire construction of the cheesecake.

Looks like it’s time to clean the cupboards again.

Do you have any good solutions to keep weevils at bay?

  • whenever i bring grains, flours,etc home from the bulk food store the package goes into the freezer ( i used to keep it there for 48 hours until i was told by an exterminator that the bag should stay there for a week– the little buggers can survive 48 hours in the freezer.) when i put the grains,etc into their container in the cupboard some bay leaves go into the bottom of the container and then on the top. haven’t had this problem in years.

  • All good advice, including the blueberries. We’ve had our share of weevils, and I never threw anything away because of them. Sifted them out, well, some of them. The extra protein won’t hurt you.

  • I am glad to hear that they are not harmful and I too have had problems with them I had to throw away all my food because I thought I had to. Then I put bayleaves in all my other containers. I felt bad about the food I had to toss. That seems to have helped and have not seen any more in anything with bayleaves in it. but I did have a problem this year about ants I found ants in my cat and dog food so I put bay leaves in the container and killed all the ants that I could see with my hands put the lid on the container leaving the bay leaves in the container and came back 2 hours later and there were ants all over trying to get out of the container so I killed all those ants and wash the lid and then put the lid back on the container and then left it for a few hours came back more ants but there were less, killed all them and then put the lid on the container tand waited a little longer and I did this tell all the ants have come out of the container and there were no more ants I continue to use the container that had the cat and dog food in it and when I got to the bottom of the container I didn’t see any remains that there had ever been any ants in the container so that is how I got the ants out of the cat and dog food. I am so glad to read about the weevils it was very helpful thank you for writing it.

  • Try a cloth bag or teabag filled with carob powder, my grandma told me it repelled weevils and it seems to work. If any carob sifts out of the bag it really doesn’t show in the flour(but maybe that’s because I’m using whole wheat flour), raw carob is a very light brown.

  • we had this problem and a moth problem rather severe when we moved into our house. Tried everything! then, my mom said to snap a dog flea collar and leave it in the cabinet. % flea collars and twice cleaning the cabinets- No more moth larvae invading everything! Now ,if I see a weevil after I freeze anything from the store, I put in a collar. I haven’t had to do that for several years.

  • I read this in a public place and finally had to lay my head face-down on the table because I was laughing so hard. The cheesecake fiasco almost caused me to have an asthma attack. I suggest adding black sesame seeds to your pantry supply and claiming that the piperine in black pepper is such a great anti-inflammatory that you’re experimenting with new flavors…they’ll be surprised when the ‘pepper’ flavor is barely noticeable. I loved the article!!

  • with any grain or rice and flour bugs are still bugs. they need oxygen. even the vacuum packing leaves some. I use the hand-warmers sold in the hardware store. they warm the hands by oxidation of metal. !!do not open the inner bag!! when the outer bag is opened feel if it is getting warm if so it is still good. I pit mine inside a toilet paper tube and roll the ends closed. drop it in with the food you want to save. it uses up the oxygen and kills the bugs and if eggs hatch they die too. Because it is not a vacuum the pressure remains the same and no new air comes in. what is left is nitrogen and with no air the food doesn’t deteriorate as quickly. two benefits with one solution. With a tight lid the nitrogen wont recombine with oxygen. Glass bottles are best for this because nitrogen will react on some plastic. Plastics are made with toxic chemicals and can leech into food. give it a try.

  • To rid myself of weevils I have always frozen my pasta,rice,wheat and all grains for 72 hours. Never have found any LIVE weevils. To me, it is a lot easier than placing in the oven. Just an idea.

  • how about putting the flour/grain in a microwave for a few seconds (say ten to twenty seconds) to kill off the eggs/insects?

  • Put an unwrapped pice of spearmint gum in your flower… rice and they won’t hatch.

  • Grampa M.

    how about an article on what harm will they cause if you eat them? do they carry diseases? if discovered can they be removed? if so how? We all know that an ounce of prevention is best but I was taught that it was a sin to waste food. despite anyone’s views upon religious values when wasting anything that others need. We have become a wasteful nation and things we value have become trivial because of our abundance. I follow the posting every day and save many that provide answers to my questions. I thank all who take the time to share their knowledge.


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