Weevils also known as flour weevils, grain weevils or rice weevils are small beetles that can infest dried and stored food. Sized about an eighth of an inch, these little bugs can quickly multiply in a dark corner or cupboard, and before you know, a weevil infestation can soon start eating through not only dried foods but other natural fibers in the house. Alongside drugstore beetles and cigarette beetles, they are grouped into the general description of pantry pests and, while the treatment for weevils is similar to other pantry pests, there are particular home remedies for weevils that you should know. If you have a weevil infestation and want to know how to get rid of weevils, then follow our home remedies below.
What Is A Weevil?
Globally, there are many species of weevil ranging in size and color, and adapted to eat a range of different plant material in different environments. They are a nuisance pest to agriculture, gardening, and homes.
There are three types of weevil that are considered pantry pests and while it is quite hard identifying which type of weevil you may have, fortunately, the treatment for your weevil infestation is identical.
The grain or granary weevil is common across the united states but prefers colder states. It is reddish brown in color and has strong protruding mouth parts (mandibles) which it uses to chew through grain kernels into which the females will deposit a singular egg.
The larva when hatched will eat through the grain from inside and after three days or so, will pupate and emerge as an adult beetle. The fact that they lay up to 400 eggs within a span of 5 months adds to the nightmare of a weevil infestation .
The rice weevil is closely related to the grain weevil and to the untrained eye looks almost identical. The main visual difference is that the rice weevil is not so uniform in color and has four yellow tinged spots on its abdomen. The rice weevil is more comfortable in a warmer environment and is more common in the southern states.
Unlike the grain weevil, the rice weevil is capable of flight and the presence of flying insects is the easiest way to tell the difference between the rice weevil and grain weevil.
The final type of weevil is called flour weevil or flour bug. Technically, this insect is not actually a weevil but a different species of beetle. Although it is a similar size to the grain and rice weevil, it does not have a protruding snout and on close inspection, is clearly a different species. It gets its name from the fact that it is most commonly found in flour and not stored grains. This is because it does not have the mouth parts for through eating grain kernels so prefers ground flour.
Signs of a weevil infestation
The diet of the weevils revolves around grains of various types but they will eat most organic material in the home. This includes flour, grains, fruits, vegetables, nuts, pastas, cereal, parts of plants and even dried flowers. Infestations do not just occur in your pantry
Depending on the type of weevil, you may see flying insects in and around your dried goods. Adult weevils will be visible in large numbers as they crawl all over your rice and flour.
Once weevils have infected your pantry, an infestation can quickly take hold as their lifecycle is very quick and the initial stages of an infestation often go unnoticed, as the weevils are expert at seeking out stored goods in some dark corner of your pantry.
More subtle signs of infestation may be a discoloration of flour and rice, small holes in packages and grain. Grain mold is often another sign as are small flour tracks left by weevils moving around your pantry.
If you have a weevil infestation, the chances are you will have consumed weevils without realizing when the infestation was not clearly visible. Many people wonder what happens if you eat weevils and the short answer is nothing. They do not carry diseases and are non-toxic to humans. However, they are not pleasant roommates and if you want to treat your weevil infestation, there are plenty of home remedies to get rid of weevils you can try.
1) Dispose Of Infested Food
Irrespective of the type of weevil, the only totally reliable method to get rid of weevils is to remove all infested food sources. As weevils are very small, food that looks fine may still be infected by a few individuals and if this food is not removed, your infestation will quickly return.
First, you must inspect all food sources for signs of weevil infestation. Food that has been infested should be discarded. However, if this is not practically possible, it can be treated with the hot and cold treatments described below or ‘quarantined’
2) Store Food in Airtight Containers
Prevention is always better than cure. All dried foods should be stored in airtight metal, glass or plastic containers to prevent weevils from infesting food. If you have a weevil infestation and large amount of dried food that you do not wish to discard and is not visibly infested, placing the food in containers will prevent the spread of any unnoticed infestation.
Think of it as quarantining your food supply.
If after a few weeks, there is still no visible signs of weevils, you can be assured the food is clean. If weevils begin to appear, then you should then discard it.
Do not store food in paper, cardboard or plastic bags. The weevils will munch their way through these.
3) Vacuum Your Home
Once you have disposed of or quarantined your dried food, the next step is a thorough clean. Weevils are small and easily missed and vacuuming will help get rid of weevils that have found their way onto your pantry floor or shelves.
Vacuuming will not only catch individual insects but will suck up spilled grains that are usually the first food weevils find to lay their eggs in.
Clean every crevice and crack. Include shelves, cupboards, drawers behind the stove, behind the fridge etc. Leave no area untouched. Deep cleaning techniques should be used.
4) Neem Oil
Studies have proved the effectiveness of neem extracts in controlling pests’ presence in stored products . Neem oil is also used commercially to protect crops against weevil and other pests.
Neem extracts interfere with the physiological functions of weevils thereby preventing them from reproducing, causing their population to reduce. Neem extracts also negatively impact mating, development of eggs and laying of eggs.
Spray neem oil in areas where weevils frequent. To see results, you need to continue spraying for at least a week.
5) Cedarwood Oil
Cedar oil causes osmotic dehydration and suffocation for mature weevils when they come into contact. It also dissolves their larvae and eggs. Additionally, cedar oil emulsifies the insects’ body fats leading to death (3).
Apply cedar oil to shelves, cupboards and pantry floors. Spray cedar oil in any area where you may find weevils. Regular application of cedar oil after an infestation is also recommended to avoid a reoccurrence.
6) Eucalyptus Oil
Eucalyptus essential oil is also an effective home remedy for weevils. Regular use of eucalyptus oil prevents weevils from entering your home and garden. Studies have proved that eucalyptus oil protects plants from rice weevils .
Add two to three drops of eucalyptus essential oil in 2 cups of water. Add liquid detergent to it and mix well. Pour it into a hand-held spray bottle and spray in areas where weevils have been present.
An essential oil spray is particularly useful for treating hard to reach places such as shelves, cupboards, behind stoves etc.
7) Diatomaceous Earth
Studies have proved the susceptibility of rice weevils and maize weevils to Diatomaceous Earth . This natural product will rapidly and effectively kill weevils including their larvae by desiccating or scorching them. Application of DE will eliminate or suppress a weevil infestation.
Sprinkle DE in and around the areas where you find weevils. To prevent weevils from affecting your plants, you may sprinkle DE around the base of plants.
8) Boric Acid
Boric acid is far less toxic to humans and has a wide range of industrial applications, but it also kills many insects including roaches and weevils.
When weevils come into contact with boric acid, they ingest the boric acid when they groom themselves. Boric acid negatively impacts oviposition of weevils , and disrupts their reproductive cycle.
Simply apply boric acid on surfaces where weevils move about.
9) Weevil Pheromone Traps
Weevil pheromone traps greatly reduces the presence of weevils in your home and garden. Pheromone smell attracts weevils , which are drawn to the trap and get caught in the sticky base.
Traps will only ever reduce the population, they will never get rid of weevils completely. They should be used a way of checking to see whether you still have a weevil infestation. Set the traps in your pantry and cabinets and keep a constant check on them. If you are still finding weevils in your traps, it will certainly mean that weevils are still present.
Freeze treatment requires placing the food in the freezer at a temperature below zero Fahrenheit for at least four days.
Be aware that although the temperature will kill the weevils and larva, the insect bodies will remain in the food. Eating dead weevils is not harmful but certainly not to everyone’s taste.
Likewise, freezing will not remove bad odors, or food discoloration.
If freezing is not an option, heat treatment can also be used. Place the food in the oven for an hour or until the food is heated through at 140 deg. Fahrenheit. Weevils cannot survive at this temperature and it is still low enough to not cook many dried foods.
However, like freezing, some foods will change taste and texture if heated to this level so you will have to use judgment.
Dos And Don’ts
- Buy dried foods in smaller quantities so it is easier to store and makes a weevil infestation less likely.
- While buying food, check if the packaging is intact.
- Store food in airtight containers.
- While placing a bay leaf in the flour is generally recommended, there is no scientific evidence that it will work. However, placing bay leaves in your food does no harm and may work to repel weevils to a small degree.
- Do not add old food to new food. Keep separate at all times.
- Check for weevils regularly.
- Do not let the spills be. Keep your pantry and shelves clean.
- Do not use essential oils near fire and heat sources as essential oils are inflammable.