help with moth id

Question: Hi,

I'm hoping you can help me identify some moths that are in my house. I'm familiar with grain and clothing moths but don't think these are either. They are dark brown, 5-8mm in size with a golden stripe down the back and a tan dot on their side. They look very much like a diamondback moth, but I've caught about 50 in my bathroom. It's possible they came in on a houseplant I put outside last summer, but I'm unsure because none of my houseplants have any larvae damage and they aren't brassicas...

Any help you can give would be great, I'm unable to find the source of the moths - any larvae, webbing, etc... Hoping identifying them can lead to a clue as to what they are eating. 

Appreciate it!

responder: An Ask Extension Expert Replied June 14, 2023, 11:09 AM EDT
response: Crystal: I am still working on the moths. They do not matcha ny storage pest that I know of yet. Am still doing some research. I have some additional questions that will help me if you can answer them. Where exactly did you find these moths? How many ants are you seeing, and do you know where and when they showed up? What are they doing? I think the problem is moisture related for both the moth and ants. Thanks for working with me on this. Rich

responder: The Question Asker Replied June 14, 2023, 12:51 PM EDT
response: Hi Rich, thanks for your response and help!I’m finding these moths primarily in our upstairs bathroom. I’m using a clothes moth trap in every room in our house and they are also attracted to the same pheromones (they are also attracted to light). There are 30 of the moths in the trap in the bathroom since June 4th (we’ve also killed many more whenever we see them). Every other trap in the house only has about 4 moths in it so I feel pretty certain that the source is in that bathroom. We started seeing them about a month ago and have been deep cleaning since then. We’ve pulled the light fixtures down, cleaned the vents/ducts, every crack in the cabinets, behind the mirrors, under the boards around the tub, washed all linens, and at this point we’ve run out of things to clean and check but are still finding moths.I’ve looked carefully through all the plants and their pots and I can’t find any larvae, damage, webbing or anything in the bathroom so am completely stumped on ID and where they are coming from. They look very similar to the diamond back moth but since there is no damage to the plants it doesn’t make sense what the larvae could be eating as my understanding is diamondback moths attack brassicas. Diamondbacks also have a pretty short life cycle so I can’t imagine that they overwintered on the plants I had on the porch last summer that have since been inside for the last 9 months.We aren’t worried about the ants, they are a nuisance yes, they come in every spring and go to the sink and then back out. By summer they stop doing it for the rest of the year.Thanks for your help, let me know if I can answer any other questions!CrystalOn Jun 14, 2023, at 8:09 AM, Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied June 16, 2023, 12:52 PM EDT
response: Crystal: This is not the Diamond Moth. That being stated I am going down my list of what I might expect to find in a bathroom such as yours. Some environmental factors keep coming to my mind regarding these moths:  Moisture.House Plants.Ongoing for at least 9 months now. (They are breeding somehow and, in some place.)What and where is their food in the larva stage? (Organic matter)Only in the upstairs bathroom.Certain that the source is in that bathroom.Can’t find any larvae, damage, webbing or anything in the bathroom. (I would not expect you to see them or damage) Thoughts & Questions: If the larva form of these moths feed on organic matter such as what is found in the plant pots and/or in the bowl under the plant pot no direct damage to the plants will be seen and you will not see the larva. Do these plants have bowls to catch water and if so, are they wet and/or is there organic matter in these bowls? Do you have any plants in other parts of the house (other bathrooms)? I do believe there is a connection with your plants. Thanks for working with me on this. Rich