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Pest Control/Indian moth moths-can't find source


QUESTION: Hello.. Wondering if you could please help.
Back in June 2013, I brought some perfume boxes home from my work storage unit...a facility that was open to others to store too.  Upon opening a box in my basement..a moth flew out...not knowing moth types, I just went to Home Depot bought moth pheromone traps..the pantry moth type and set a few in the rafters of the unfinished basement.  I would periodical check them...nothing was found.  I figured I just had had a stray come home with me straggler from some adjoining storage unit.  Fast forward last year, May 2015.. We began to see moths flying around.. I re-checked the traps, and wow, they were full of  moths.  The Unfinished basement, we used as storage, and had koi fish food down there. And a lot of other stored items.
….. by the time we got a handle and figured out what we kept seeing flying in basement were IMM it was August 2015 ..we took out a lot of clutter and bought new traps and took out fish food and a ton of stored stuff that we had down there. Fish food we took out and put in storage shed..waited all summer no larvae developed!!!! Last year we did NOT find the actual source and only saw dead larvae after a thorough cleaning around the window sill, dead larvae around an old ant bait trap. Never a nest, mainly dead one in traps and the flying ones we killed. Mid October 2015.. We stopped seeing them, and we’re told by an online pest shop they hibernate in cold (we’re in Michigan) and not to be surprised if we see them again in the spring…well mid May 2016.. They’re back… Not any where near the amount last year and we no longer see any flying…one in the trap very few days or stuck on the fly traps I hung up..thinking they’d attract females??… Again, NOTHING EVER upstairs in the kitchen (last year I had kept traps upstairs for a while and never caught or seen any upstairs and was told to remove them as they’ll attract them from downstairs.)… I keep ALL food upstairs in fridge and even took the step to cover all vents and basement door is always closed and when we go down there we are so careful coming back up.  And  this year emptied the basement down to virtually empty, had an exterminator out who searched and cannot find any food source.. He has sprayed twice at 30 day intervals.. finding dead ones now on floor more then get caught in traps...but we're still catching I traps even after 2 sprays and so much clearing and clean up) He recommended removing/ changing insulation around perimeter of basement its from 1992…. Could be a source of nesting behind it).. We’ll be getting foam kind to seal any cracks)also to see if maybe we missed an old ant bait trap or what could be sustaining them??? We are at our wits end... It's a 1500sq ft unfinished basement, very clean and empty at this point and no know food down their!!
Could we be dealing with reminants from last year this far into this season??? Again we are seeing them abating but just want to be done..but then again we have had the area sprayed which helped abate the issue too. It has consumed my husband and I with non stop cleaning and searching…we thought they could be coming from outside but the Windows we have down there are glass block with no vents.. And unless they are doing komakazee moves to come in??? Please if you could give us some insight??Thanks and sorry for being so long with this message!!!

ANSWER: Linda,

Once Indian meal moth becomes established they can be very difficult to completely eliminate especially in older homes and buildings. While reading your story the possible scenario that popped into my head was that mice may have carried some of the fish food into a hidden cache, such as inside a wall, which became infested with moth larvae. This is actually a fairly common scenario for a number of household pests. What you are doing is fine, keep using the traps to monitor the population (see Use them upstairs as well, they won't "attract" the infestation. I'd skip the exterminator treatments as they won't do much good in this case. If ALL food sources are properly stored the infestation will likely burn itself out eventually or at least decline to a level that you can live with. The moth does not pose a threat to health nor will it damage the structure. BTW, they are NOT coming in from the outside (Michigan is far too cold for this tropical moth to survive outside).

Jack DeAngelis

---------- FOLLOW-UP ----------

QUESTION: Hi!! Thanks for the quick response... We've never had a mouse issue in the home. We are pretty up on this as it has never been an issue with any infestation until these moths popped up last year. The only issue we ever had was ants which is why we had any bait in the sills around the perimeter.  So you're saying we may never rid ourselves of these??? It's not something we want live with!! I know they're harmless but it doesn't help knowing that they still around?? Again if there is no food will/ should they eventually die out?? Thanks so much!!!

I doubt that the ant bait has any thing to do with the moths. Eliminating ALL sources of food (for meal moths or ants) is usually not possible without extreme measures so modern ideas around an integrated pest management approach is to accept some damage (pest presence), especially if the damage is minor. I still think it is possible there's a hidden cache of the fish food that is the source of the moths. Good luck, sorry I can't be more specific.

Jack DeAngelis

Pest Control

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Jack DeAngelis


I can answer questions about the control of pest insects, spiders, mites and related arthropods. These household pests include termites, carpenter ants, powderpost beetles, nuisance ants, bed bugs, cockroaches, fleas, wasps, and many others. I can also answer questions about using pesticides and other pest control tools such as baits and traps.


I am a retired university extension entomologist. I've taught and conducted research in urban and agricultural entomology. I've published over 70 extension publications, 20 research publications and several books about insects.

Ph.D. in Entomology

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