Does Freezing Flour Kill Weevil Eggs?

Weevils are common pests that can crawl into anyone’s pantry or cupboard. Perhaps you’ve recently found a few in your flour and tried to get rid of them. Now you’re wondering how you’re going to deal with the eggs. Could freezing be an option? We’ve done the research to give you the answers to help you get rid of these pests and save the flour in your kitchen.

Yes, freezing flour can kill weevil eggs and other life stages (larvae, pupae, and adult). Keep the flour inside for 3 to 7 days in a freezer set at 0 degrees Fahrenheit.

If you would also like to learn how to prevent the problem from coming back or would like to know if there’s another way you can get rid of weevil eggs, keep reading, and we’ll give you what you need. We’ve also provided other information on weevil infestations that you might want to know.

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A glutenfree buckwheat flour for baking in the bowl on gray background, Does Freezing Flour Kill Weevil Eggs?

How do you kill weevil eggs?

Freezing infested flour can kill weevil eggs. In a study by Finn and colleagues, they found that 0% of weevils can survive at 0 degrees Fahrenheit. Freezing can also eliminate other stages of life and other weevils as well.

Accordingly, Iowa State University says that freezing the flour for 7 days can be enough to salvage infested products, while other sources report 3 days. However, in the study we mentioned earlier, they said that the longer you keep the flour at low temperatures, the less likely the eggs will survive. Therefore, you might want to keep them in there for a week.

You can also use your oven to get rid of flour weevil eggs. Just heat it to a temperature of 140 degrees Fahrenheit, and put the flour inside for 15 minutes. Like freezing, this also works for other stages and other kinds of weevils.

Flour in a bag on the table and spikelets

How long does it take to get rid of weevils?

Apart from the 3 to 7 days with freezing and 15 minutes in the oven we mentioned earlier, it’s hard to determine how long it will take to get rid of weevils in your pantry. There can be another infestation if there are live eggs left behind or if there are still some adult weevils left alive.

How do weevils get into flour?

Weevils get into flour through breaks in the packaging. Some products may have already been contaminated straight from the mill. Flour weevils also tend to lay their eggs in the crevices of any packaging, so by the time it is opened, they can also infest the product.

Can weevils get into sealed packages?

Weevils can get into sealed packages, but it depends on the material it’s made of. They can chew through unlined cardboard, thin plastic, and aluminum foil, so be sure to check products in those kinds of packaging for any holes or tears. If the packaging is sealed and not something the weevils can chew through, there are likely none. 

How do you know if flour has weevils?

You can tell if your flour has weevils by spotting the adult insects or their larvae in the packaging. For home settings, you will usually find the red flour beetle. Adults are about 0.1875 inches long, with a metallic, reddish-brown hue and an elongated oval shape. 

Tribolium confusum known as a flour beetle in white background

They aren’t true weevils, so unlike rice or grain weevils, they do not have the typical long snout. Accordingly, their larvae are light-brown and worm-like with six legs. 

Other signs of weevils in your flour can be an unpleasant smell coming from inside the packaging, holes in the flour bags, and the flour has a grayish tint.

Can you use flour that had weevils in it?

You can use flour with weevils, provided that there were only a few. Also, you should heat or freeze the flour before you use it. If you found several weevils, and the flour has changed smell or color, throw it out instead. In that case, using the ingredient might be unsafe.

How do you get rid of weevils?

Aside from the eggs, you also have to get rid of the adults that lay them. Here are measures you can take to do so:

1. Take things out 

Upon discovering that you have weevils, start by taking out the contents of your pantry or storage space. If you can, find the product where most of the weevils are coming from, and throw that out. Check any unsealed bags, opened containers, and unlined cardboard boxes for any adult insects or larvae as well.

2. Check On Things

Accordingly, assess the packaging of other products in your pantry for any tears or openings. These can be a way for weevils to get into other products and cause a reinfestation, so it is best to be thorough. If you suspect that any weevils got into any open or unsealed products, it would be best to throw those out. But if you would like to avoid wasting products, you can try to save them by freezing or heating them in the oven, which we will discuss later.

3. Clean up

Vacuum cleaners can remove weevils that remain in the pantry and any stray grains that could attract more. Pay special attention to the corners or cracks to make sure you get all the places where the insects might be able to survive. You can also take the opportunity to dust off and clean the pantry or storage space in general.

Pesticides are unnecessary, and other measures such as ammonia or bleach also do not provide much benefit. Also, it might be harmful to use pesticides in a place used for food storage.

4. Seal things up

Before you put return the products to your pantry, transfer them to sealed, airtight containers. If some of your products stored in these containers had weevils, take out the contents and then clean them before reuse.

Finally, if you feel that you have an infestation that is too much to handle, call a pest control service. 

Tips to prevent weevils from getting into your pantry:

  1. Try to look over the packaging of the flour or grain before purchasing it. Any holes or tears in the packaging could mean contamination and can be a way for an infestation to start.
  2. Occasionally check the products in your pantry. If they are in packaging that weevils can chew through, look for holes or tears. Also, check opened products for any adult weevils or larvae.
  3. Regularly clean your pantry, and remove any crumbs or grains spilled inside because those can attract insects.
  4. Freeze the grains or flour in a tightly sealed before storing them. You can also store them in the freezer.
  5. Weevils are attracted to moisture, so keep your flour or grains somewhere dry.
  6. If possible, transfer your products into airtight containers. However, try not to mix newly bought grains or flour with older batches inside the containers. Also, clean the containers thoroughly before reusing them.
  7. Buy your grains or flour in small but reasonably-sized batches which you can consume. If you have too much, it might spoil and attract insects.

Final Thoughts

Weevil infestations can be hard to manage. Sometimes, the problem keeps coming back, which results in wasted food and frustration. However, with proper cleaning, food storage, and the other steps we’ve mentioned, you might be able to eliminate these pests for good. But always remember that professional pest control services are always available if the problem is more than you can handle.

If you want to learn how to get rid of other insects that could be troubling you, such as fleas and bed bugs, then check out these articles and more at ForFreezing.com.

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