Meal Moths Leave Slimy Trails In Your Food

If you ever opened a box of cereal, spotted movement, and found slimy trails all over the flakes, chances are you have meal moths laying eggs, and making babies in your food.

Doesn’t sound too appetizing does it?

Thinking about the name you’d think this moth only invaded flours and such items as corn meal. But that just isn’t the case. I’ve seen them in a number of different foods – including cereal and dog food.

I remember well a couple of calls I had as an active pest control technician. Both of them came from a local university.

The first call was to a student apartment building. The occupants of one apartment had moth-like bugs flying around the living room and kitchen areas. As soon as I entered the apartment, and looked into the kitchen, I knew the culprit was the meal moth.

That was easy enough to figure out as the adults were flying all around. The infestation had grown for a while so there were a lot of them in the air. Most of them in the kitchen.

I started looking through the cabinets until I found the one the insects were concentrating in. That particular cabinet had dry food boxes, some of which were cereals. I opened, and inspected, a number of the boxes until I finally opened one cereal box. When I looked inside I found the slime trails. They’re lacy trails, and an off white in color. Those trails pretty much covered the cereal inside the box.

The slime trails are left behind by the meal moth larvae. An adult gets into the container to lay its eggs. This normally is a container that’s been around a while, and rarely gets moved. The eggs hatch, and the babies grow by eating whatever food they hatched out in. The slime trails are the stuff they leave behind as they poop out their waste.

After a few days the babies grow up, get their wings, and leave the food container to fly around as adult meal moths.

I told the person living in the apartment what the infestation was, and explained to him that when grains sit unused for long periods that these moths see them as excellent breeding grounds. And I told him that the cabinet contents should be discarded after they get old.

I didn’t find any infestation in the other foods so I just tossed the cereal box in the garbage, and headed off for my next appointment.

The other call I got about meal moths surprised me. This one was to an office.

When I first got to the office I saw some moths flying around, and others hanging on the walls. After a close look I recognized them as meal moths, but didn’t understand why they were infesting an office space.

I asked the occupant if she stored any cereals or other grains in the office. (I didn’t see anyplace where that type of food might be stored except possibly her desk drawers.) She told me she didn’t keep food in the office.

I kept looking around from the doorway. It was a small office, and there wasn’t room for me to get far inside because of piles of books and paperwork covering most of the floor. She also had a large dog in the office with her.

I asked if she kept any other edible substances in the office, and after a few moments of thought she said the only thing was food for the dog. So I had a look in the dog food bag. It was one of those 50 pound bags, and sure enough there were the trails of slime that the larvae of meal moths leave as they grow into adulthood.

She said that she only brought the dog with her once in a while, but kept the dog food there all the time. That meant the bag of dog food got pretty old because it sat under her desk for long periods without her dog eating from it.

I hung a moth trap to catch the adults, and told her she needed to throw the dog food away. I also suggested that rather than keep dog food in the office her best action would be to carry a single day’s supply from home on those days when she brought the dog to work with her.

Meal moths are a nuisance when they’re flying around your kitchen, and you have no idea where they’re coming from. Your best bet to keep from suffering an infestation of these bugs is to go through your flours, cereals, and grain foods occasionally – and discard any that are older than a few months.


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