You open a bag of rice or flour and something flutters out. Pantry moths have usually been in the cupboard for weeks before you see the first one.
A pheromone trap draws in the males and brings breeding to a halt. More usefully, it shows whether the problem is shrinking or not, which is exactly what you want to know after clearing the cupboard. There is nothing in it but a pheromone, no pest control product. Lasts up to 3 months.
Are pantry moths dangerous?
No. They do not sting, do not bite and will not make you ill, and infested food is not toxic either. You still throw it away, but for another reason: infested products contain webbing, droppings and shed skins, and you do not want to eat those. In large quantities those residues can also trigger allergic complaints.
What does the life cycle look like?
This is the key to the whole problem. A female lays up to two hundred eggs, usually near or inside a food source. The eggs produce larvae, and that is the stage that feeds and does the damage. After a few weeks they pupate, often not in the product itself but in a corner of the cupboard or against the ceiling, and then the cycle starts again. Egg to moth takes about six to eight weeks, less when it is warm. That is why the problem returns if you only chase away the flying moths: the next generation is already inside the packaging.
Do pantry moths go for pasta?
Yes. Anything starch based is a target: pasta, rice, flour, muesli, nuts, dried fruit, biscuits, chocolate, spices and pet food. Cardboard boxes and paper bags will not stop them, because the larvae chew straight through. Even a folded over bag is no protection. Airtight glass or plastic jars are.
How do they get into the house?
Almost always delivered with the shopping. The eggs are already in the product when you buy it, and only hatch once they reach your warm cupboard. It is not a question of hygiene, and it happens to everyone.
Where should you look?
Not just in the packets. Check the seams of the shelves, the top of the cupboard, the edge of the ceiling and the corners behind the jars, because that is where the larvae pupate. A cupboard that looks clean can still be full of pupae there.
How to tackle it
Empty the whole cupboard, throw out infested products and store the rest airtight. Wipe the shelves and seams with hot water and vinegar. Then hang a trap and watch for two to three months to see whether catches drop. If they stay level, there is still a source somewhere that you missed.