How to get rid of Grain Weevils

Having to deal with a grain weevil infestation can be a troublesome experience. As grain weevil larvae develop on the inside of the kernels and emerge only in adulthood, after they have eaten most of the kernel from inside-out, you will discover their presence usually too late. Getting rid of the infestation usually means disposing of all the goods that have been affected as there is no way of recovering them and reuse them. Eliminating all other products that could attract weevils, and making sure you thoroughly clean the surrounding of your storage unit will be the first steps in making sure you eliminate any trace of adults and larvae as well.

Determine the degree of infestation

As with any type of infestation, you will need to inspect the surroundings and establish the degree of infestation. First check the older and opened packages you have in your pantry, to see if their contents show signs of infestation. Then move to the newer packages and leave nothing untouched. Throw away any product you have found that shows signs of infestation. In the case of kernels, they would be showing signs of holes, as the adults have already emerged from them. Otherwise, it will be quite difficult to establish if the products have been affected or not, as you will not be able to see the larvae hidden inside the kernels of grain. However, even if you just suspect and infestation is taking place, it is better to dispose of everything that might have been affected. Weevils are quite common and often unavoidable, as they can enter your home even in pre-packed food such as cookies, crackers, biscuits, pastas or breakfast cereal.  As a single female can lay up to 400 eggs, you can imagine that an infestation can easily occur and the adult emerging weevils will soon spread to the other products you have in your pantry.

Get rid of weevil infested products

At the slightest sign, get rid of any product and clean your pantry thoroughly. The best way to do this is by vacuuming every corner after taking everything off your shelves. Make sure you insist near cracks and crevices, as weevils might be hiding there and they can survive several weeks without any food source. You can also use soapy water or a rag soaked in water and vinegar to clean the shelves, as this will kill any remaining weevils and removes their chemical traces which could attract other weevils in the future. Gather the vacuumed weevil debris and the infested food items and pack them in new, sealed, plastic bags before throwing them away. This will ensure they will not escape and return, as just one weevil is enough to begin another infestation. Also, make sure you always clean spills and any other debris from your kitchen, to avoid attracting any weevils back to your property.
When buying new products, don’t mix them with the older ones, and rotate your stock, in order to always use the older products, so that you do not give the weevils time to develop in a forgotten bag in the corner of your shelf.

Deter grain weevils from your pantry

If you are not able to see any signs of infestation, but you do want to be sure your products have no traces of weevil larvae in them, you can place them in the freezer. You can seal them in a freezer bag and keep them for 4 days. This will kill off any eggs or adult weevils that might be hiding inside. You can also store food items in the freezer if they need a long-term storage. However, be sure not to store them in plastic bags, when moving the products back in your pantry. Weevils can chew through plastic or cardboard, so the best containers to use are glass or metal ones, with tight closing lids.
You can also choose the heat method, and spread your products on a baking sheet, in a preheated oven to 48°C, and leave them there for an hour. You can also use the microwave, but keep in mind that heating seeds for gardening can also destroy their chances of germination.

In order to avoid having products infested with weevils, you can place dry bay leafs inside the containers as their smell will discourage the weevils, but won’t change the quality or taste of your products. Another way of making sure weevils do not get the chance of developing is by using the products you bought as soon as possible. Buy them in small quantities and use them within the first month of purchase, as afterwards, chances of weevil infestation grow bigger. Other natural products such as cloves can be spread through your pantry and places on shelves, near your containers. Their smell will deter weevils and keep your grains safe, and the same will happen if you place an open matchbox near your products. The sulphur smell will keep the pests away, while not affecting the taste or smell of your food.

Spraying concentrated insecticides for Grain Weevils control:

Concentrated insecticides are the most common used products in fighting insect infestations. They provide the safety that any insect coming into contact with the treated surfaces dies shortly.

Using chemicals against weevils is not really an option, as they live and breed in your food. The only time you can apply some aerosol insecticide is when cleaning your pantry and all the food products are taken out of it. After vacuuming and washing down the shelves, you can apply insecticide, especially in the corners and near cracks and crevices, but be sure to let the pantry air before restoring all the food containers.

Sprayers used for Grain Weevils control:

The equipment needed for a professional Pest Control Operator depends on the type of pest the treatment is made against, and if the treated surface is indoors or outdoors. Sprayers help in applying products meant to reach difficult places, as well as guaranteeing an economic control of the treatment application.

Otherwise, you can use some organic versions of pesticides, such as pyrethrins. You will not risk contaminating your food with chemicals, as this is an organic compound, derived from flowers, more exactly from Chrysanthemum cinerariifolium. It can be used near food as it has no chemical basis, and it can easily target the insect’s nervous system. It has biodegradable compounds and it is considered to be a low-toxicity pesticide, taking into consideration the human health standpoint. However, even if choosing to use pyrethrins, avoid spraying it directly on food, and leave the cupboards open for a couple of hours before refilling them with food products.

Dusting insecticides for Grain Weevils control:

Dusting insecticides are ideal for areas where liquid insecticides can not be sprayed, such as cracks and electrical installations. Apply on dry surfaces, do not dissolve in water. It is very important to identify and treat areas with high potential of nests. Careful of air flows!

Make sure that after you have removed the infested food, thoroughly cleaned your kitchen and pantry and replenished it with new and fresh food items, you take into consideration the possibility that another infestation can easily occur. To avoid this, always keep your kitchen clean, make sure you stock your pantry with fresh and small quantities of items, always use the older ones first and store them in the proper types of containers. For more tips on how to ‘Prevent infestations with Grain Weevil’ from taking place, check our related article, and keep in mind the fact that once the weevils have taken shelter in your pantry, replacing every infested item will prove to be costlier that applying the necessary preventive measures and avoiding this situation in the first place.