If you see pantry moths fluttering in the cupboard this summer, sorry, but their larvae are likely munching on your dry goods.

The 12-millimetre-long pantry moth can do a lot of damage to staple items, creating flaking cobwebs in flour, or a powdery residue in a fruit-and-nut mix.

And perhaps even more stomach churning, the larvae are so small, white and pale that we’re sometimes ignorantly eating these little grubs.

“Once you see the moths flying around the kitchen or pantry you’ve already had a problem for days or weeks, you just haven’t noticed it,” University of Adelaide entomology Professor Andy Austin told The New Daily.

The path to the kitchen

The pantry moth, also known as the Indian meal moth, would have been introduced at the time of, or not long after, the arrival of the First Fleet in Australia.

The sailing ships that transported dry food to the colony were infested with pantry moths. Commercial dry food producers and transporters are still battling the insects today, Professor Austin said.

He explained the larvae of the pantry moth feed on dried food, such as grains, wheat, feed, dried fruit, nuts, flour and even pet food.

When adult female moths lay – sometimes in the order of 400 eggs – they lay their eggs on or near food. When the eggs hatch and unleash tiny caterpillars, they wander in search of something to eat.

“The adult moths are quite good and have sensory structures to assist in finding potential food for its offspring,” Professor Austin said.

This means the larvae are often in the food you buy, and the moth’s eggs are known to even live within the plastic or cardboard packaging of food.

“Often cardboard and thin plastic packaging is not sufficient enough of a barrier for the tiny larvae and they burrow their way in,” Professor Austin said.

How to treat an infestation

If you find cobwebs or a floury residue in your food, pull everything out of the pantry. Inspect each item, remove and dispose of any infested food and put remaining items in airtight plastic or glass containers.

It’s also crucial to thoroughly clean cupboard shelves, where moth eggs or larvae can live in small cracks and crevices.

“Even if containers don’t have food in them, larvae could be wandering around,” Professor Austin warned.

Professor Austin also recommended freezing dry food items if you’re unsure if food might contain eggs and larvae.

“Most freezers reach minus 20 degrees, and in three to four days it will kill the larvae,” he said. “It’s a good non-chemical way of dealing with a problem like this.”

But as the temperature gets warmer, the life cycle of the pantry moth can speed up from as long as 305 days to 27 days, sometimes making it a hard battle to win.

“They can persist for a while. But if you deny them anything to feed on, eventually they will die or go away,” Professor Austin said.

Preventing pantry moths

There are a number of botanical solutions online promising to prevent pantry moth infestation, from adding bay leaves to a few drops of peppermint or eucalyptus oil to the pantry shelves.

Other useful tips include:

• Inspect food for possible infestation before you buy. Look for webbing in the food or small holes in the packaging;
• Store food in tightly sealed containers. Professor Austin recommends glass jars with a rubber seal and metal levers;
• Clean up food spills straight away and pay attention to cracks and crevices; and
• Vacuum problem areas in the kitchen and empty to prevent re-infestation.

And as unappetising as pantry moths are, Professor Austin said they pose no risk to human health – unlike other critters that can carry diseases, such as blowflies and cockroaches.

“People don’t like them for obvious reasons, but thousands of people a day are eating pantry moths.”