Keeping your dried foods free from infestation is not something most people think about until it’s too late. Yet every home owner at some stage will most likely have to deal with an infestation at some point. Many species of small beetles, often referred to as ‘pantry pests’ can infest stored food products at any time such as carpet beetles, grain beetles, cigarette beetles and of course, the drugstore beetle. While the treatment for each beetle is broadly similar, we do have our own handy tips to get rid of an infestation for each species. If you have a drugstore beetle infestation, then try our home remedies for how to get rid of drugstore beetles.
What is a drugstore beetle?
The drugstore beetle (latin name: Stegobium paniceum) gets its common name from its old-fashioned habit of infesting drugstore medicinal herbs. However, today, while the name has stuck, the beetle is just at home eating common pantry dried foods such as pasta flour, grains etc, but will, unfortunately, eat almost anything dry ranging from pet food to dried flower arrangements.
The drugstore beetle is a hard-shelled, reddish brown beetle between 1/16 to 3/16 inch in length. The larva of the drugstore beetles are white and grub-like formed in a crescent shape. The adults lay their eggs in the food itself and while the larvae grow, they will shed their skin several times and then pupate before finally emerging as an adult to breed and start the cycle again. Depending on temperature and scarcity of food, this cycle can be repeated up to four times per year. Given the quantity of eggs laid per cycle, infestations can occur at an alarming rate.
Many people wonder whether drugstore beetle bite or are harmful to humans. Fortunately, they are not harmful and they do not bite. Likewise, they are not known to carry any diseases so are just considered a pest.
Signs of a drugstore beetle infestation
The signs of drugstore beetle infestation are quite obvious especially if it’s your pantry that has been infested. First off, you will often see flying beetles in or around food sources. Small holes in packaging may appear as the adult beetle emerges to seek a new mate. The larva will shed their skin and defecate in food, while the adult the beetles will leave behind the pupa. All this is visible in the food as are the larvae themselves. As they will eat almost anything, drugstore beetles have been known to infest other parts of the home, eating through books and manuscripts and even wall hanging game.
How to get rid of drugstore beetles
1. Remove infested food.
Irrespective of the beetle species you are dealing with, the only totally reliable control method is to locate and remove all infested food sources. There are natural insecticides available (see below), but if the source of the infestation is not removed, the drugstore beetles will simply recolonize your pantry or home.
2. Seal off uncontaminated food
Food that shows no sign of infestation should be sealed in airtight plastic, glass or metal containers. These containers will obviously keep out drugstore beetles from re-infesting the food, but more importantly, if an infestation was still at the early stages and perhaps you missed some of the signs, by sealing the food this will stop the beetles spreading out again. After a few weeks check the sealed container to see if there are any signs of beetles before storing the food normally again.
Do not store food in paper, cardboard or plastic bags. The beetles will munch their way through these.
Once you have removed or sealed off all food sources, a thorough vacuum cleaning of the pantry and indeed the entire home can effectively help get rid of drugstore beetles. The purpose of the vacuum is really to remove all spilled food sources that may still have drugstore beetle eggs present.
The focus of the clean should in every crevice and crack. Include shelves, cupboards, drawers behind the stove, behind the fridge etc. Leave no area untouched.
Once you have cleared all foods away and thoroughly vacuumed, then there are several options for using a natural insecticide to help get rid of drugstore beetles. Vacuuming and clearing infested food alone may well be sufficient to solve your infestation problem, but we recommend using a natural insecticide to be totally sure.
A great natural insecticide to use is boric acid. Boric acid is non-toxic to humans (unlike standard commercially available insecticides) but is extremely effective against all beetles including our drugstore critters. (1) Buy boric acid in its powdered form and sprinkle liberally across floors, shelves cupboards as well as into cracks and crevices. Leave overnight before vacuuming up.
Boric acid will dissolve in water and can be used as a spray to get more even coverage or access into hard to reach places. The solution will kill adult and larva and eggs of the drugstore beetle.
Diatomaceous earth is another natural insecticide that will kill drugstore beetles, the larvae, and eggs. It works by desiccating and scorching the beetles. (2)
You can apply diatomaceous earth as a powder in the same way as you would use boric acid, by sprinkling liberally over all shelves and cupboards etc. Most importantly, select food grade diatomaceous earth that isn’t injurious to your pets and is safe if there is any spillage in your pantry. You should try and avoid breathing the powder so wear a mask/respirator when applying the remedy.
Pheromone traps are available for drugstore beetles. The traps are used commercially in warehouses for stored dried food. The traps contain pheromones which lure the male beetle to a sticky end. However, they are not used to eradicate the beetles but more to provide a degree of control. They are placed hexagonally across warehouses and by checking the quantity of trapped beetles for each trap, you can ‘triangulate’ the source of the infestation. For a non-commercial use, you may wish to maintain a trap after you have treated your infestation to check whether you have truly irradicated the problem. If you are finding trapped beetles after you have treated the problem, then you haven’t really treated the problem.
If for some reason you do not wish to discard infested food, you can treat the food to get rid of the drugstore beetle infestation. If the drugstore beetles have infested books or hanging game, this is also the treatment to use. The drugstore beetle and its larva cannot survive a deep freeze. Cold treatment requires placing the food in a freezer at a temperature of below 0 deg. Fahrenheit for at least four days. However, some foods are spoiled when frozen so you will need to use judgment. Freezing however, while it will kill the beetles and their larva, it will not remove dead insect bodies, fecal material, bad odors or discoloring of food.
Like freezing, no animal likes being overheated. If freezing is not a suitable treatment for a food, heat can be used. Quite simply place the food in the oven for an hour or until the food is heated through at 140 deg. Fahrenheit. Drugstore beetles cannot serve at this temperature and it is still low enough to not cook many dried foods. However, like freezing, some foods will change fast and texture if heated to this level so you will have to use judgment.
Essential oils to get rid of drugstore beetles
Essential oil are nature’s natural insecticides. The application of cedar oil across work surfaces, shelves and cupboards etc helps eliminate drugstore beetles in various ways. Cedar oil causes osmotic dehydration and suffocation to mature beetles, it also dissolves their larvae and eggs. To add to that, cedar oil also emulsifies the insects’ body fats and finally kills them. (3)
Neem oil is also a great naturally insecticide which can be used to get rid of drugstore beetles. It works differently to cedar oil in that the active compounds found in neem oil destabilize the functioning of the insects’ hormonal system. (4) Consequently, the insects stop eating, mating, laying eggs and even flying. When eggs are laid, they fail to hatch. Eventually, the population of drugstore beetles fails to regenerate and dies out.
As mentioned, neem and cedar oil are the best essential oils to get rid of drugstore beetle eggs and larvae naturally. There are many other essential oils that also have insecticide properties, such a peppermint, clove oil. Use of essential oils as insecticides can often come down to a preference for fragrance.
When applying essential oils against the beetles, it is best to make up an essential oil spray. As oil is insoluble in water, it is best to first add the oil to alcohol or some vodka if pure alcohol is not available. Add ten drops of oil to alcohol, stir well and then add half a pint of water before placing the mixture in a spray bottle. The oil will dissolve fully in the vodka and can be sprayed from any handheld sprayer and be used to spray shelves, cupboards, behind stoves etc. An essential oil spray is particularly useful for treating hard to reach places.
Do’s and Don’t’s of drugstore beetles
- If you have an infestation, it is advised to discard all your dried food. It is likely that the food which appears bug-free may well also be infested.
- Mix essential oils with alcohol to a make drugstore beetle spray. Mixing with water will not dissolve the oil.
- Game should always be closely inspected. Use the freezing method to treat it
- Make a habit of storing dried foods in air-tight containers. Prevention is the best long term strategy.
- Rotate all dried food. Use older food before more recently purchased food.
- Do not stockpile large quantities of dried food unless necessary. The worst infestations occur in food that has been stored and stock-piled for a long time.
- Don’t use essential oil sprays around open fires or near heat sources. They’re highly flammable and can ignite.
- Don’t spray boric acid solution on dark surfaces as it has a bleaching effect