Tuesday, September 18, 2012

silent battles - the flour moth

A few months back I purchased some flour straight from the mill. It didn't take long before I realized that I had brought home more than I bargained for.

One night, sitting at my computer, a moth flew itself to smithereens on my desk lamp. This has happened on many a summer night before, but this moth.... was different... It didn't look anything like the variety in your walk-in closet that eats favorite lambswool sweaters beyond the point of repair.

Within a day of not giving it another thought, there were a dozen of them and my moth terror alert shot from green to defcon1-red. Didn't I read about these some where? 

Comparing a fresh, crisply burnt corpse to the mighty array of disgusting pictures to be found on the Internet, I realized I was under attack by the Mediterranean Flour Moth!

Life Cycle

The moth is pale grey and about a ¼ up to ½ an inch long. On its wings it has two zig-zag lines. They are not the brightest bugs of the bunch; it's very easy to catch them when they are 'resting'. They have a very characteristic pose: it extends its forelegs, and with their little heads raised up in the air it gives the whole creepy bug a sort of sloping appearance. It actually looks like they are 'on alert', but if you are ever unfortunate enough to make your acquaintance with this pest, you will find they can be picked from the ceiling or the wall without them ever seeing you come. Be careful though, especially on white walls, because they are quite 'dusty' and will leave a gray smudge.

Their life cycle takes about 10 weeks. The female moth lays between a 100 and 700 (!) little eggs. Here it starts to get disgusting; they lay their eggs in your flour. But make no mistake about it (I did!); these little rascals may be called 'flour moths', there is a lot more they fancy than flour alone. They also love dried fruits, nuts, chocolate (!), beans, breakfast cereals and grains. The eggs will hatch in the right circumstances within a few days. The larvae will immediately start spinning a cocoon right there in your flour. They remain there until fully developed, which can take up to more than a month.

Little white strands of silk in your flour is a tell tale sign of your flour being 'infected'.

When they are fully grown larvae, they head away from the place they were born to look for a good place to turn into a moth. At sun up or sun down they will venture out to find themselves a nice location, typically a crevice or a little hole in your cupboard or in a tiny crack in the wall or on your ceiling. They stay there for another two weeks or so before emerging  a full fledged flour moth.

make moth flour out of your flour moths!

Make no mistake about it; it is not easy to get rid of them without radical measures. When you notice the little strands of silk in your flour, there is basically just one thing left to do; throw it out!

The next thing to do is making sure the flour that isn't affected remains that way. Don't be tempted to leave a bag of flour out in the open, because they will hone in on it like... well, like flour moths I suppose. Make sure you transfer all of your flours into airtight (and I mean AIRTIGHT) containers as soon as you bring them into your house.

There are a number of non toxic pheromone based moth traps out there that will assist you in exterminating them, but quite frankly; it takes quite some time to trap them all, since they are only effective on fully grown moths and not so much on the larvae.


If you want to get rid of them (relatively) fast, like I did, you will need to be drastic. Thoroughly check all of your food items, and I mean ALL,  for signs of infection. If in doubt, throw it out. And don't only check the content, be sure to check all the folds and crevices on the outside of any bag in your pantry as well; this is where they love to hide!

Clean out your entire pantry and check every nook and cranny for signs of larvae. Check, check and double check; these creatures are very creative in finding the places you hadn't thought of. For example: I found one larvae in each tiny pre-drilled hole of my cupboard used to move around my shelves! Use a skewer to poke around in any hole big enough to house the little buggers.

With your cupboard thoroughly inspected and your pantry or kitchen spic and span you might think you have conquered the pest. Think again, because you will only need one male and one female survivor to start the whole pest cycle all over again.

I ended up repainting my entire kitchen after finding a few more nifty hiding places in the walls of my kitchen, far away from any food source. This finally did the trick.

After this whole operation, make sure to keep checking for at least 40 more days to nip any possible survivors in the bud before calling it a victory, but I'll assure you; you WILL, if this ever happens to you! A moth trap is most efficient in this stage. Just make sure not to put too many moth traps in, because it tends to confuse the moths. One or two traps make a distinctive source of pheromones that they will come and check out!

The most important lesson to be learned here is to not let anything enter your kitchen from a source that you could call risky. Check all flour before it enters the house, especially when it comes from a 'non industrial' source like organic mills and the likes. Invest in a nice array of airtight containers,  immediately transfer your flours into them and you should be safe!

I hope you never have to come and visit this page, but if you ever have to, I hope the tips will help you get rid of them fast!


  1. Oh, God, I had them once, they drilled into every package of flour, nuts, and so on. Gross! I got rid of them by placing everything in airtight plastic containers - but in those days I didn't have 50 lb flour bags to deal with. I just saw something today that looked suspiciously like this moth....

  2. It happened to us years and years ago, brought in with a bag of stonemilled cornmeal i had bought at a farmers' market in Pennsylvania. It took many months, the disposal of ALL plastic bags or cardboard containers in our pantry and the washing and repainting of said pantry before we eliminated the problem (these pests reproduce and propagate at an astonishing speed and there is almost nothing they don't like). So yes, do keep your staples in airtight boxes, preferably clear. That way if you see something is going on inside, you can dispose of the stuff safely without contaminating anything else. A harsh lesson to learn! Sorry it had to happen to you.