Small moths flying out of the pantry, webbing in a bag of flour, or tiny holes in rice and grains all point to stored-food pests. They breed inside the food itself, so the packet is the source of the problem, not the cupboard.
Which pest is it?
The Australian Government Department of Agriculture lists the main stored-product pests in its pests and contaminants of grain and plant products reference. The ones most often found in household pantries fall into three groups.
Indian meal moth. The adults are the small moths seen flying at dusk or dawn. They are short-lived and do not feed. The damage is done by the caterpillars, which burrow into the food and spin silk as they go. The department notes that infested food becomes contaminated with silk, droppings, cast skins, pupal cases and dead moths. It lists oats, rice, wheat, nuts, spices, peas, beans and lentils among the foods affected.
Weevils. Rice weevils are the small beetles with a snout that turn up in rice, wheat and other whole grains. The department says females lay 300-400 eggs, each one in a small hole chewed into the grain and plugged with a waxy secretion. The new adults leave through a small round emergence hole, so grains with neat circular holes in them are a good sign. Adult weevils can fly, which is how they move from one cupboard to another.
Other beetles. Saw-toothed grain beetles are more often found in dried fruit and oilseeds than in cereals. Warehouse beetle larvae get into packaged food, and the easiest sign to spot is the cast larval skins left among the food.
Where the moths come from
Moth eggs are laid on the food at dusk or dawn. A female lays 150-200 sticky eggs, which stick to whatever they land on. Because the eggs are laid on the food and the larvae live inside it, the first sign is often weeks after the eggs were laid, when the larvae have grown and the adults start flying.
When the larvae are fully grown they leave the food and wander looking for somewhere to pupate. That is the stage most people notice, as caterpillars on shelves, walls and ceilings, and it is why moths keep appearing after the first packet has been thrown out.
How to clear a pantry
- Take everything out of the cupboard, including tins and jars, and check each packet. Look for webbing, clumped flour, small holes in grain, and larvae.
- Bin infested food in a sealed bag and take it out to the wheelie bin the same day. Do not leave it in the kitchen bin.
- Freeze unopened packets you are unsure about for several days, or keep them sealed and check them again in a few weeks. Cold treatment is a common way to deal with eggs and larvae inside a packet.
- Vacuum the shelves, corners, shelf-pin holes and the join between the shelf and the wall, then wipe down with warm soapy water. Larvae hide in these gaps while they pupate.
- Put flour, grains, rice, pasta, nuts, dried fruit and pet food into airtight containers with a tight seal. Bags and cardboard boxes do not stop either moths or weevils.
- Check the rest of the house for stored food that sits for months, such as birdseed, pet biscuits, spare packets in the laundry or garage, and sealed bags at the back of cupboards.
Buy smaller quantities of flour and grain if they sit for months, and use the oldest stock first.
What a pest controller can and can't do
The pests are in the food, so the food has to be found and removed. No spray or treatment to a cupboard fixes an infested packet. If you have cleared the pantry and the problem keeps returning, it usually means there is another packet or container still infested somewhere else in the house.
Stored-food pests are often found alongside other cupboard and bathroom insects. Silverfish like the same dark, undisturbed corners and cardboard, and if you are also seeing cockroaches, the cockroach control service covers that side of the kitchen. For a visit to check the rest of the house, a general pest treatment looks at the cracks, corners and entry points around the kitchen. Our treatment does not replace throwing out the infested food. To ask a question or book, contact us.
Common questions
- Are pantry moths harmful to eat?
- The insects are not known as a health risk, but the food is spoiled. Infested food ends up contaminated with silk, droppings, cast skins and dead moths, so it should be thrown out rather than sifted.
- Will a pest treatment get rid of pantry moths?
- The pests live in the food, so the food has to go. Spraying a cupboard does not fix an infested packet. A pest controller can help with other insects in the same room, but clearing, cleaning and sealing the pantry is the part that ends the problem.
- Why do I keep finding moths after I threw the flour out?
- Moth larvae leave the food when they are fully grown and wander off to find a place to pupate. They can end up in corners, on ceilings or in other cupboards, so one packet can seed several spots. Check the rest of the pantry and wipe down the shelves and corners.
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