The Indiana Meal Moth
May 2025 Edition:
By: Levi Farrell, A.C.E.
The Indian Meal Moth
If you have ever bought, sold, or been in the presence of seed, food, spices, starches, feed, grass, nuts, or pet foods…or have been in an establishment that produces any of these. Chances are, you’ve encountered an Indian Meal moth. You have come face to face with the most widespread stored product pest in the world. Lucky you.
With a 21-day lifecycle, yes just 3 short weeks from egg to adult, the ability to lay 200 – 400 eggs per female, and great flying abilities, it’s no wonder they’ve earned this title. Although the adult moth is very fragile and easily managed using just about any ULV(ultra-low volume) products readily available, this is not the stage to be concerned about. Adults have 1 job, create more moths. They cannot eat and are unable to cause any damage, except aesthetically, when present in high numbers. This stage’s longevity is short-lived, only 7-10 days.
The larvae on the other hand are very robust. Roughly 2/3 of the insect’s life is spent in this stage. This is when the damage is caused. Chewing mouthparts allow them to penetrate packaging and attack product. When extremely high numbers are present, the webbing spun by the larva can obstruct air movement causing temperatures to increase and spoilage to accelerate. The fifth instar larva is the hardiest stage. The insect is just about to pupate at this stage in its life. It can enter diapause during this stage and easily weather cold temperatures, ULV treatments, and fumigation. I personally found this stage alive outside at 10°F.
It's no wonder that so much time has been spent developing products to manage this insect. You must truly throw the entire tool kit at it to maintain control. Products such as mating disruption used in conjunction with ULV treatments usually do well. If the population is left unchecked, a fumigation is needed most times. Use monitors to keep an eye on what’s going on. The industry tends to call them traps, don’t fall into that trap! Pheromones are only attracting the males, let’s estimate that to be 50%. Of that 50%, 10% is what the typical monitor will get. If you see 10 moths in your monitors, a rough estimate of the population in your structure is 200 adult moths.