Is It Safe To Eat Beans With Weevils?


It’s after dinner when I decide to soak the beans I kept in a jar a month ago for Baked Bean dinner tomorrow. As I scoop out the beans to cook, I noticed brown insects floating in the water. On close inspection, I see some beans have holes. If you worry about bean weevils, here’s what you should do.

Bean weevils are not harmful to humans or animals. Eating beans with weevils is safe and digest assuming the beans cooked correctly. Heat eliminates any trace of bacteria or parasites in beans.     

Having tiny insects crawl and fly past the pantry area is a cause for alarm. You wonder where the weevils came from and how can you stop them from scattering all over the house.

Facts About Bean Weevils

Bean Weevils or Seed Beetles are granivores that feed on seeds, beans, lentils, chickpea, soybeans, and other legumes.

It can live its life on a single pod of a bean while on its larvae and pupae stage. The adult weevil will venture out of the bean and feed on bean plant foliage and seed pods.   

Weevils do not bite or cause harm to humans. But they are a disturbing threat and headache for the Agriculture industry.

Weevils can get to a pile of beans left in the storage. It may look safe and untouched by the elements, but upon closer inspection has already been attacked by the weevils and other bugs. 

Once a weevil has laid its eggs on a pile of beans, it takes on a new cycle. The larvae molt into pupae until it becomes an adult. They play dead when disturbed in a stockpile and will start moving after five minutes.

Bean Weevil Life Cycle

A weevil starts as an egg inside a bean seed. It will hatch into a small whitish worm that’s called the larvae. After a few days, the larvae will molt and become a cocoon or pupa. Another few days pass for the pupa to claw its way out of the bean seed as an adult weevil.   

Adult weevils can live for 21 to 80 days.

A female weevil deposits eggs on bean pods in the field or whole beans in a storage house or stockpile of beans.

She can lay up to 60-100 eggs and will do her job of finding a new source of breeding ground if the current one is heavily populated and infested. 

What do Weevils Eat?

Bean Weevils are internal feeders that bore their way into a bean. From the larval stage, it makes a tunnel through the bean pod and settles within the seed. It eats the inside of the bean until the pupal stage. 

When it becomes an adult weevil, it makes an exit hole and climbs out of the seed coat. Adults weevils will feed on bean plant foliage and seed pods, no longer on the bean pods.

Can Bean Weevils Fly

Adult Bean weevils crawl and fly in an infested bean storage, as well as the piping of a house to get inside. They fly in search of a new source of bean storage.

The old one where it came from is likely heavily populated and infested, forcing the female to look for other places to lay its eggs.

Can You Eat Beans with Weevils

Many delicacies have insects as exotic dishes, and eating beans that had weevils is no different. The eggs of a weevil may still be inside the bean, and cooking the beans will kill any bacteria and parasites from the weevil.

The innocent farmer will lay the beans flat on the ground under the sun to ward off the adult weevils. The eggs stay inside the beans and continue their cycle while the farmer shovels the beans for packing. 

Others wouldn’t mind the crunch that comes with the beans. Like earthworms vegetable worms, you can consider it another protein ingredient. An estimate of 100 grams of weevils will give you 6.7 grams of protein content.  

Side Effects of Eating Beans with Weevils

The beans packed with weevil eggs have lessened in nutritional value. Because of the hollowness of the bean, it does not have the meat inside its pod.

There may be a change of flavor and taste of staleness from the weevil’s excrement. You can solve this problem with a good boil and a flavored seasoning to the beans.

Bean Weevil Damage to Food

Dry Beans can last as long as a year if they are weevil-free, but it can last as long as 25 years in a perfect storage method.

Oxygen is the cause for the bean’s natural fats to degrade and go rancid. In humid areas, it can start to mold and you have a party of weevils growing healthier when left attended.

Another aspect is when the larvae that molt into pupae will shed their shells and still stay in their breeding ground. It has excrements that they shed off while they grow into adult weevils. Those factors contribute to the bacteria and parasites. 

How Do Weevils Get Into Beans

Female Weevils will drop off its eggs wherever it sees a pile of bean harvest or in a garden area where it spots a pod that its eggs can settle and crawl their way. It takes only one weevil to lay 60 eggs in any place to start a whole army of weevils.  

There are different ways the female will lay its eggs. Some will choose a crack of the bean pod, while others will glue their eggs on a pod. As long as they see a seed, they will lay its eggs there. 

Farm Weevils

The female weevil flies through different areas in search of storage areas where she can lay her eggs.

Once the weevil drops off the eggs on a pile of beans, the larvae will snip an opening to bore their way inside a seed. It continues its feeding until it molts into a pupa, then the adult weevil will chew its way out of the seed coat.   

Weevils thrive in warm and heated storage conditions. Even in the wintertime, when farms have climate control conditions to store beans, the weevil will keep breeding as if it were summertime. It can emerge at any time of the year and breed continuously.

Garden Weevils

A female weevil will search for areas to lay her eggs, and this can reach your garden. Look around you and if you see a pod of bean seeds. It could be a green pod, a bean plant foliage, or seed pods.

Home Weevils

In the home setting, weevils come with the dried bean package that you bought from the grocery. You must look closely at the packaging if it has any small holes or tear because the weevil could have set up camp either from the warehouse or the grocery store.

How to Tell if Beans Have Weevils

The most obvious tell-tale sign is the presence of an adult weevil when you open the bag of beans.  The eggs remain hidden inside the bean so you’ll only see small holes in the bean itself that tell you the larvae has set up a tent inside the bean.

How to Preserve Beans from Weevils

Preserving the beans starts from the time you get out your grocery in the bag. Transfer the beans to an air-tight container when you get home and contain them right away.

Do a quick check of the cartons and plastic bags to see if there are any holes. There are different ways to kill any remaining eggs that can turn into an adult weevil.

Microwave for at least 5 minutes

You can kill the eggs of a weevil in a microwave setting of five minutes at a high temperature. It will only apply to beans that you plan to cook, not for beans you want to sprout

Heat at 120°F for two hours

Setting up the beans on a tray and popping them in the oven is another way to kill the weevil eggs.

You can use a temperature of 120°F- 140°F for two hours. It is for cooking beans, not for sprouting them.

Put in freezer for at least 3 days

Freezing beans for 3-7 days will kill the eggs of beans and will not hinder the seed from sprouting.

You will have to wait for the beans to come to room temperature and dried-off any moisture before you store them in an air-tight hard-body jar.

Take note that if condensation happens in the container, the seeds will spoil due to moisture.

Use of Oxygen Absorbers

Oxygen Absorbers are individually packed iron powder, sodium chloride, and activated carbon on a porous sachet or aluminum pack.

The purpose is to take out oxygen or moisture from the beans that the eggs will need to survive. This practice will not affect the sprouting process of a bean either.  

How to Store Dry Beans

Storing beans is the next step after you screened the beans from any weevil presence. The preserving suggestions will keep your beans weevil-free.

But keeping it protected until you use the batch of beans will guarantee you do not get weevils in your beans.

  1. Keep beans in an air-tight and hard-body container in a cool dark place. You can use mason jars, vacuum sealer containers, or vacuum hard-cased plastic containers.
  2. Label your beans and indicate the date of your purchase to follow the first in-first out practice.
  3. Beans placed in a sealable freezer bag can last a few years. Once you take them out of the freezer, you have to either use the beans or dry them up to avoid condensation.
  4. Vacuum seal your beans without any moisture or air, then place in a hard case with a lid to avoid accidental puncture or a new attempt of the weevil to eat through the plastic.
  5. Use an oxygen absorber in a mylar bag when you pack the beans and seal it.
  6. Remove any broken beans or rocks that you notice before transferring them to the container.
  7. Divide your beans into how much you would cook and label them according to the date.
  8. Use food-safe, air-tight buckets that have hard-cased bodies and stackable for your bean.

How To Get Rid Of Bean Weevils In The House

Getting rid of weevils and insects in the house is not a difficult task. Just remember to do the following reminders judiciously and without fail.  

  1. Keep a keen eye for any holes or tear in the packaging of a bean bag. This is the first clue that a weevil has entered the package.
  2. Soak beans in water. Adult weevils will float to the top, making it easier to remove them.
  3. Contain any possible infestation by separating items in air-tight containers, and if a weevil shows up in the container, it can deal with it individually.
  4. Stick the infested container in the freezer for seven days to kill the weevils and the eggs.
  5. Clean the storage area, in particular the shelf of dry goods. Wipe with a solution of water and white vinegar for antibacterial and antifungal properties.
  6. Vacuum the walls and windowsills of the house where the bean weevil likes to hangout.
  7. Repair or seal any cracks or holes that you see in the windows or doors of the house as these are entry points for the weevils
  8. Check for any broken screen windows or doors and immediately repair the screen as this is another entry point of the weevil.

How to Prevent Bean Weevil Infestations

The bean weevil that flies to the side of a house door, bidding it’s time to enter, is something you can control because of the advantage of their tiny size.

Much as you’d like your house to be free from any pests or insects, you can try to prevent them from entering the house through simple steps.

You can, however, prevent infestations from happening in our homes, but it’s an ongoing process.

Keep Kitchen Shelves Clean

You need to remember that sanitation and cleanliness is the first step to preventing weevil or any pest infestation.

That means proper cleaning of shelves and sweeping of the floor in the pantry or cabinets. You wouldn’t know if there was a piece of bean that fell out of the bag when you grabbed it out of the grocery.

Remember, it takes a single bean pod for larvae to grow into an adult weevil.

Examine Foods that Bean Weevils Eat

It’s not only a pod of seeds, beans, lentils, chickpea, soybeans, and legumes that weevils feed on.

They can feed on corn, nuts, and dried grains. Weevils can also approach fruits and vegetables that have seeds lying on the counter and feed on those.

Determine if Affected Food can be Heated or Frozen

Most weevils of the grain and bean family cannot survive in frozen temperatures and the freezer for seven days.

In the same way, baking the food at 120°-140°F for two hours can be done for beans and dried food. Some will flatten the food in a tray and leave it out in the sun for a few hours during the high heat of summer.

Keep Food in Air-Tight Hard-Body Containers

All dry foods have to be transferred to air-tight and hard-body containers to stop any adult weevil from biting the cardboard or plastic bag. This puts a stop to the entry of weevils into the food source. It allows you to check on the container and see if there are weevils present and deal with the problem one at a time instead of going through a mystery guess of what food is infested.

Practice First In-First Out

You must segregate the old bag of beans from the new ones, not mix them just because they are the same kind.

First In First Out (or FIFO) method simply means that the old beans must be used first for the simple reason that you don’t want the beans to go rancid or stale, but you can’t risk mixing the new bag of beans without checking the bag of any weevils. 

Do Not Overstock on Dry Food

It’s important to keep what you need in the pantry that will last a maximum of one month, rather than keeping something that will sit on the shelves for half a year.

This presents the problems of stale food and wasted money. It also becomes the perfect breeding ground for weevils and mites who like to feed and breed in the food source. 

Check the Temperature of your Pantry

Weevils thrive in warm and humid environments, and your pantry is not an exception to the rule.

Most pantry areas are dark, warm, and humid. It would be practical to air out and keep the door open for a few minutes a day every time you get something.

You get in good circulation that will dry up any moistened area.

Keep Pet Food and Bird Seeds in Different Area

It would be a good idea to separate dog food or cat chow from the pantry area.

You may want to keep it in the basement or a hard bin in the garage area. This lessens the chances of a desperate and hungry weevil from going through your pet’s food. 

Photo credit: Frank Peairs, Colorado State University, Bugwood.org

Wyatt Welch

Hi, I am Wyatt, and I live in North Carolina. I've been working as a Pest Control Technician and now I am enjoying my retirement. This blog is a perfect outlet for me to share my knowledge in the field and I'd be happy to help if you have any questions.

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