What do mealworms eat?

October 11, 2015 3:10 PM

Having attempted several rounds of trying to rid my pantry of mealworms, I find that they are back because apparently they eat chocolate?? What else do I need to throw out/seal up besides flour, rice, quinoa, cookies, etc.?

They seem to be getting into regular old plastic containers as well as jars with old rubber on the seals. Do they eat nuts? Dates? How far do I need to go with this? All the information on google I can find is how to raise them as pets. WHY. I WANT THEM GONE.

posted by transient to Home & Garden (25 answers total)

I had to assume they ate everything, a threw out anything that wasn't in a brand-new sealed container. I bought plastic and glass jars with good seals for the rest, took everything out of the pantry, wiped down the shelves and walls very very well, and have been paranoid about them ever since. They were in pretty much every kind of food package I had.
posted by third word on a random page at 3:29 PM on October 11, 2015

I had a moth infestation once. Every time I thought it was solved, they'd turn up somewhere else. My solution was to put everything in mason jars. Then, if there aren't already eggs in the food, the container is guaranteed sealed against infestations.
posted by aniola at 3:32 PM on October 11, 2015

Dried fruit, spices (paprika!), nuts, oatmeal. Chocolate, yes, also cocoa powder.
Yeah. Throw everything out.
posted by Omnomnom at 3:32 PM on October 11, 2015

TEA. Friggin' tea.
posted by Omnomnom at 3:32 PM on October 11, 2015

You can also store some foods in the freezer if you don't want to change containers.
posted by aniola at 3:32 PM on October 11, 2015

Are they actually larva form of pantry moths? They like spices, nuts, herbs, spices, flour, pet food, bird seed, pasta, candy, etc. Bird seed is totally the worse, I won't have it in the house anymore. Pet food can also be a big problem, so tightly sealing it, and getting it out of the house will help. Not leaving the pet bowls out all the time can also help.
Inspect all packages for signs of infestation and get them out of the house. They can chew through plastic bags, so you want tightly sealing plastic or glass containers. The eggs look like tiny gross spiderwebs. Clean everything as well as you can, this might take a couple of rounds. Pheromone traps will kill adult moths, you can get these at hardware stores. Freezing items for a week will apparently kill them, as will microwaving on high for 5 minutes, or baking in the oven at 140 F for an hour.
Sorry, so gross!
posted by florencetnoa at 3:33 PM on October 11, 2015

Mine actually started in the laundry room, I found eggs and larvae in some of my cleaning supplies. Don't skip cleaning the non food areas in the kitchen.
posted by florencetnoa at 3:37 PM on October 11, 2015

Also, they thrive in all the foods you don't look into regularly (once a week). So check those right now.
I found ten of those feeding onthe crumbs behind the bread box once.
Check for hidden crumbs.
posted by Omnomnom at 3:40 PM on October 11, 2015

I just got them from dog food. They are absolutely exasperating.

In my case, the dog food is actually kept on the other side of the house from the kitchen, and they all went into my bathroom (humidity? I don't know) and a bunch of them (but not enough of them!) landed on my towels and I guess dehydrated to death? I don't know, but they sure did like my towels. I just saw one in the kitchen area and am checking everything to make sure they haven't gotten into the dry goods.
posted by Lyn Never at 3:45 PM on October 11, 2015

Cornmeal! Also dried mushrooms and seaweed. Seconding putting EV.ER.Y.THING. in Mason jars.

Also I recommend pantry moth pheromone traps. They got rid of a terrible infestation, and we haven't had a problem since.
posted by ottereroticist at 4:16 PM on October 11, 2015

Oh gods, my sympathies. When I had them, or a related insect infestation, I basically just threw everything away. Every time I thought, oh it's safe to keep these nuts that have been in a plastic container (or similar) I then discovered the little fuckers in there. I kept cleaning for days and they kept coming back. Finally I read something online that pointed out if you have contact paper or similar kind of sticky shelf-liner thing, they often lay eggs under it and keep breeding. Got home and pried up a corner and sure enough, there they were. Get rid of it, nuke it from orbit, put down clear is my advice.

Oh, and apparently bay leaves are also a natural deterrent if you are odd about having chemicals around your food (as I am).
posted by Athanassiel at 4:24 PM on October 11, 2015

Just assume that they will eat everything and anything that is in your pantry. They will also get into any cardboard box and find their way into all different kinds of storage containers.

Here is how I tackled my moth/mealworm infestation a few summers ago:

x. Took everything out of the pantry
x. Threw away anything that had mealworms or moths living in it.
x. Put things like rice, pasta and flour into the freezer to be left for at least a week to kill any eggs/weevils
x. Gave the pantry a good clean with hot soapy water. Absolutely every surface!! Don't forget the bottoms of shelves and the sides of the pantry etc.
x. Wiped down the outside of all cans before putting them back into the pantry.
x. Set up several moth traps around the kitchen. IIRC, I had a couple in the pantry, one on the top of the fridge, a couple on the top of tall cupboards.

I had to be pretty ruthless about it. Food ended up in a couple of categories - things that were in cans and could be kept in the pantry and things that could be kept in the freezer. Anything else would have to get chucked out, because they will find their ways into storage tubs and the infestation will just continue.
posted by kinddieserzeit at 4:38 PM on October 11, 2015

Oh, Athanassiel's answer reminds me that I also bought some bay leaves and scattered them on each shelf in the pantry.
posted by kinddieserzeit at 4:39 PM on October 11, 2015

Thanks! I just did that (I have a bay plant in my living room).
posted by transient at 4:59 PM on October 11, 2015

I had a pantry moth problem a few months ago. I couldn't find the source at all, so wiping down cabinets and throwing things out didn't help, those stupid things were still around. What did help was buying some trichogramma wasps online. Within a week, the number was dramatically reduced, within two weeks they were completely gone. I haven't seen a single moth since. I was hesitant to go to pesticides due to having pets in the household, and this was a cheap and pesticide-free solution. I highly recommend it!
posted by Fuego at 5:29 PM on October 11, 2015

My neighbor told me what you do is freeze for two days, that kills the living. Then leave out for two days and the eggs quicken. Then freeze again for two days, and the cycle is broken. The tale, I had flour moths all over one year then they finally subsided. Years later my daughter and I take a pair of nineties printed stretch pants from my closet shelf. My daughter asks me why there are maggots on my pants. I say, "What else is up here?" And lo and behold there is a round piece of card board with nuts, seeds, and maccaroni glued on, in a pattern. My daughter made it in school, when she was seven, I saved it in the closet. It was the source of everything, and still working it eight years later.
posted by Oyéah at 6:32 PM on October 11, 2015

In college, I developed the defensive but also delicious habit of keeping breakfast cereal in the refrigerator. Zero pests.

More recently, I realized that my baked goods benefited from fresher flour, which is helped by keeping the flour in the freezer until it's needed. Now I keep a bunch of stuff in the freezer that night seem unusual, but it works great for freshness and makes those items utterly beyond approach for insects.
posted by amtho at 7:13 PM on October 11, 2015

This is one of my specialties (previous comments on the subject). First, your best search terms are "pantry moths" or "indian meal moths."

Second, they don't only eat grain products. They'll eat almost anything. They can get into sealed containers, because adults lay eggs on the containers and the larvae migrate into the food while still at a microscopic size.

Third, the traps are only partly effective as they only trap non-egg-laying adults - so they kill the pest at the end of their lifecycle, but the infestation easily continues because the eggs are laid before that. So, they help cut down on the flying guys but they're not enough on their own.

Fourth, I've had them twice in two different homes. The only way I got completely rid of them was to (a) throw out just about all food and foodlike stuff in the pantry/cabinets, (b) thoroughly scrub all cabinet surfaces - taking note that sometimes the larvae can live in things like shelf paper glue; and (c) store absolutely everything I bought thereafter in the fridge or freezer. Keeping this up for several months took care of it. To this day I still store flours in the fridge. I also put almost all food that comes from the store in cardboard or plastic into glass storage jars when it gets home. They like cardboard and package glue, so getting rid of that helps, and they have an easier time getting through loose cardboard seams than tightly shut glass containers.
posted by Miko at 7:13 PM on October 11, 2015

Styrofoam. Really.
posted by alex_skazat at 8:35 PM on October 11, 2015

Complicating problem is that I live with two housemates and our fridge and freezer are perpetually crammed to the gills as it is. I threw out everything that was openish and everything that looked like it had the spiderwebby things in it, and wiped down all surfaces.
posted by transient at 7:43 AM on October 12, 2015

You'll probably have to be more Draconian than that. I know it costs money to throw away "good" food, but if you see signs of a continuing or returning infestation, you'll probably need to toss everything that's not in a sealed metal can and start fresh. Good luck in the interim, but be ready to take that next step if needed. In my experience the halfway approach just was not sufficient to get rid of them permanently.
posted by Miko at 8:07 AM on October 12, 2015

Fuego, were you left with the wasps hanging around afterwards?

We already have a bunch of stuff in good glass jars from the last few rounds.
posted by transient at 8:07 AM on October 12, 2015

Thanks Miko. We just have so much stuff. It may come to that if they come back after this.
posted by transient at 8:09 AM on October 12, 2015

The wasps are tinytinytiny, so you don't even notice them once they are hatched. Microscopic is accurate in this case. They survive as long as there are larvae for them to eat--once they've taken care of the problem, they die out too. I assume they made up a bit of the dust around the house once they died out, but otherwise, there was no indication that they were around at all other than the lack of pantry moths.
posted by Fuego at 8:48 AM on October 12, 2015

florencetnoa : Freezing items for a week will apparently kill them, as will microwaving on high for 5 minutes, or baking in the oven at 140 F for an hour.

If you have a deep freeze, one day at -5F will do it as well. It's the USDA standard for killing fish parasite eggs, IIRC. Temperature sterilization is time-dependent.
posted by IAmBroom at 12:52 PM on October 12, 2015