1479 Indian Meal Moth Plodia interpunctella (Hübner, 1813)

My father recently 'phoned from London to let me know that he had a moth infestation in his house and try as he may, he could not get rid of it. From what he was saying I could not be certain what the moths were. I visited him within the week but regretted the fact that I had forgotten to pack any moth books for reference.

I was shown a store cupboard where my father keeps nuts and seeds to feed the birds and squirrels. There was a series of black smudges on the cupboard walls, door and ceiling where some moths had met an untimely end. "Good riddance!" was my father's curt response after I asked him what the smudges were. "They keep appearing each week and it's been like it for several months," came his rather impatient retort. He then handed me a jar with holes in the lid. Inside were about a dozen or so adults and rolling around in the bottom, several hundred eggs.

Indian Meal Moth was my hunch since the moths had a distinctive Pyralid appearance but never having encountered this species before, I wasn't certain. The larvae, from my experience with The Lesser Wax moth in bee hives, move away from the feed material even eating their way through thin polythene. They are reminiscent of white elongated maggots when fully grown and spin a silken cocoon in which they pupate amongst darkened nooks and crannies. The reason my father had been plagued for months by this pest species was that he simply failed to find all the places the larvae had found to spin up and pupate in; even amongst the folds of the black polythene bags where the food material had been stored! I soon put him wise to this and the next day he had a complete clear-out of the contaminated material and containers as well as the underneath of the linoleum covering the cupboard floor!

When I arrived back in Cornwall, a quick look at Goater's British Pyralid Moths soon confirmed my suspicions that it was indeed P. interpunctella. Incidentally Goater's description (from Berne 1952) of the moth 'resting by day with wings folded, resembling a grain of black oats', is very apt. Also, 'The ferruginous, pale-based forewing is characteristic of this species.' The moth is apparently continuously brooded but the main emergence is in June and July. The moth was first recorded in Britain in 1847 (Goater, B., 1986. British Pyralid Moths A Guide to their Identification).

I include a photo of this moth from Ian Kimber's very useful web site by kind permission.

Phil.Boggis
(Assistant County Recorder for moths)