The Indian meal moth is a common household pest, infesting stored food such as cereals and nuts. Learn all about the life cycle of Indian meal moths, how to identify and control them and how to prevent infestations in the future.
As they are so common, many of us have had to deal with Indian meal moths (Plodia interpunctella) before. They occur mainly in kitchens and are recognisable by the traces they leave behind in stored food. They are also referred to as flour moths, weevil moths, grain moths or pantry moths and are pyraloid moths of the family Pyralidae. Indian meal moths are likely to have originated from the Middle East or the Mediterranean. Through worldwide trade they made their way to Europe as early as the 19th century and have been infesting homes and warehouses ever since.
Indian meal moth: facts & figures
An adult Indian meal moth is four to ten millimetres in size and has a wingspan of 13 to 20 mm. Its wings are a yellowish-grey colour near the head and a darker red-brown towards the back.
Indian meal moths live for about two weeks and do not eat once they are adults. In their short lifespan, females lay up to 300 eggs, which are approximately 0.5 mm in diameter. They like quiet, sheltered places with a large supply of food for their larvae to feed on. For this reason, they often go for forgotten food in flimsy packaging at the back of cupboards to lay their eggs in. Their larvae hatch after three to four days and may differ in colour. They moult up to five times and reach a length of up to 17 mm by the end of their larval moult cycle.
During this time, the larvae mainly live in and feed on the food around them, making it inedible due to their webs and droppings. They like to hide in webs and then pupate outside of their food supply. Indian meal moths like many dry food products, including nuts, legumes, cereals, pasta, teabags and dried fruit. Since they infest such a wide spectrum of foods and because they are very robust and have a high cold tolerance, Indian meal moths are considered a serious pest.
At a temperature of 30 °C, it takes about four weeks for the larvae to grow into adult moths. At 20 °C, it can take over 10 weeks. In Central Europe, the pest is able to produce two generations a year. In warmer regions, it can be even more.
Foods Indian meal moths particularly like include nuts, legumes, cocoa powder, chocolate, dried fruit, cereals, flour and grains, semolina, pasta, porridge oats, spices, tea and coffee. In rare cases, they may even infest fresh fruit.
How to identify Indian meal moths
Larval webs are helpful indicators – if you find lumps or silvery webs in your food, you know there must be moths in your kitchen. If the entire product is clumped together and full of webs and larval excrement, you are dealing with a severe infestation.
Indian meal moth larvae are white in colour, sometimes with a touch of red or green. Their bodies are shiny and their heads brown.
Pheromone traps are a helpful and reliable means of detecting the presence of moths. Our Plantura Pantry Moth Traps contain pheromones specifically for pantry moths. Pheromones are chemicals that are normally emitted by females to attract a mate. In sticky traps, they are used to lure the male moths, which then stick to the traps. The traps therefore enable you to detect the presence of a pest at an early stage as well as monitor moth numbers.
Please note: Since moth traps only reduce the number of male moths rather than eliminating them entirely, some will still be able to mate. Therefore, moth traps are not a control method, but are only meant to detect and monitor an infestation. Find out below how to get rid of moths entirely.
How to prevent a pantry moth infestation
In some cases, moths fly in through an open window. More often, however, an infestation will occur when we bring an already infested food item into our home. Therefore, make sure to check newly bought food in paper or plastic packaging for small holes and any damage. Also, keep your kitchen or pantry clean and check for moths regularly. We recommend storing food in sealed and airtight containers made out of glass, ceramic or thick plastic to prevent moths from getting in.
As Indian meal moths do not like cold very much, it is a good idea to store food in a cool place.
Some essential oils can also be used as a repellent by setting up essential oil diffusers. A good choice of essential oil includes peppermint, lavender, anise, geranium, lemon, cedar, orange and eucalyptus. They will not only repel moths but leave your storage space smelling lovely too.
Caution: Many essential oils, including peppermint, anise and eucalyptus, are toxic to pets like cats and dogs, even when diffused. So, if you are a pet owner, it is best to double check that the essential oils you plan on using are safe for your furry friends.
Summary – Indian meal moth prevention:
- Check food packaging for holes and damage as soon as you buy it
- Keep your kitchen and/or pantry clean
- Use sealed, airtight containers made of glass or thick plastic
- Keep food in a cool place
- Use essential oils
How to get rid of Indian meal moths
Should Indian meal moths have taken up residence in your home, you will want to get rid of them as quickly as possible.
If you find heavily infested food in your kitchen, immediately place it in a bin bag, seal it tightly and dispose of it outside. Then, check all your stored food for moths and clean your kitchen or pantry thoroughly. We recommend using a hoover in cracks and corners and scrubbing all surfaces with a vinegar-based cleaner. If you are not sure whether particular food items are infested, freeze them for two to three days or place them in the oven at 60 to 70 °C for an hour to kill any potential moths.
Chemical moth control
Insecticides such as moth sprays almost always contain chemicals that are poisonous to humans and animals. For example, even small amounts of the common ingredient permithrin can be fatal to cats. Not something anyone wants to have in their kitchen. Fortunately, there are safe, environmentally-friendly and effective alternatives, such as the use of beneficial insects.
Natural moth control with beneficial insects
Using beneficial insects is a great way of getting rid of an Indian meal moth infestation naturally. Our Plantura Ichneumon Wasps for Food Moth Control, for example, are specialised living moth killers. Ichneumon wasps have large ovipositors with which they lay their eggs directly inside moth eggs, thereby parasitising and killing them. However, there is no need to worry – the use of ichneumon wasps is safe for both humans and animals as the wasps can neither sting nor fly.
- Effective & chemical-free biological control for pantry moths
- 1 one-time payment for 4 separate lots of mini-wasp cards delivered at 2 week intervals
- Highest quality parasitic wasps - not harmful to humans or pets
Ichneumon wasps that can be used for Indian meal moth control include the braconid wasp (Habrobracon hebetor) and the chalcid wasp (Trichogramma evanescens). These beneficial insects can also be used to get rid of other types of moths, such as the Mediterranean flour moth (Ephestia kuehniella) or the warehouse moth (Ephestia elutella).
Tip: Although moth traps are not a control method, we recommend using moth traps such as our Plantura Pantry Moth Traps and ichneumon wasps at the same time. This way, you will be able to monitor the presence of moths and, in turn, your progress in getting rid of them.
Summary – Indian meal moth control:
- Dispose of infested food as soon as possible, check all your supplies and thoroughly clean your kitchen and/or pantry
- Chemical agents are effective but often contain substances poisonous to humans and animals
- For effective natural moth control, use beneficial insects such as our Plantura Ichneumon Wasps for Food Moth Control
- Pheromone traps such as our Plantura Pantry Moth Traps are used to monitor an infestation and indicate when it has been successfully eliminated
Learn more about natural moth control with beneficial insects in our article on moth control with ichneumon wasps.