What is Indian meal moth?

Indian meal moth is a worldwide pest that can affect everything from individual pantries to expansive stored grain and product facilities. Learn more about this pest and the damage it can cause in this article.

How to identify Indian meal moth

Indian meal moth is one of the most commonly encountered moth pests in the stored food product industry. This small moth is relatively drab, about half an inch long, and possesses a distinctly coppery sheen on its wings (see the reference image below). However, larvae are the greatest concern to the commercial sphere, as they are the feeding stage of the insect, and cause for most damage and concern to pest management professionals and food quality managers

Indian meal moth larvae are about the same size as the adults, although this may change by instar. They are off-white with a brown head, and relatively mobile for a caterpillar. When these insects pupate, they can often do so far from their food source, making complete elimination of this pest difficult. They will often spin silk cocoons around their pupae before emerging as adults.

Indian meal moth adult. Photo: Michel Vuijlsteke

While Indian meal moths are the most common pests of their family, several closely-related moths exist with similar behavior and appearance to Indian meal moth (P. interpunctella). Common similar stored product moths are Mediterranean flour moth (E. kuehniella), raisin moth (C. figulilella), almond/tropical warehouse moth (C. cautella), and tobacco moth (E. elutella). Because these species are closely related, pheromone monitoring and management will work on all these stored product moths. However, identification of moth species is still helpful to ensure that damage is not being caused by an entirely different pest, such as the cigarette beetle (L. serricorne).

Like most insects, the development time of Indian meal moths is determined by temperature. Therefore, in hotter climates and warmer parts of the year, facility managers are more likely to see higher numbers of meal moth, due to faster generation times. While they may enter a state of dormancy in cold winter conditions, the pest can persist year-round in facilities with artificially elevated temperatures.

Indian meal moth infestations

Larval Indian meal moths are voracious feeders that will get into and consume a wide variety of edible stored products. Among other products, Indian meal moths can infest stored nut facilities, grain facilities, dog food, maize, bird seed, dried fruit, and more.

The primary concerns with Indian meal moth damageare the food they eat and the silk they leave behind. This sticky webbing will accumulate their frass, eggshells, and other waste products over time. In addition to making product unappealing to customers, the accumulation of waste in stored product can serve as a vector for other contaminants that can spoil product for the final user.

Once an infestation of Indian meal moth is discovered, said infestation can be extremely difficult to eliminate due to the moth’s mobility and fecundity.. To a certain extent, these moths are attracted to light; however, the best way to manage and monitor this species is by using pheromone products.

Monitoring and management of Indian meal moth

The most effective way to look out for and cut down on Indian meal moth numbers in your facility is by using a proper IPM strategy including pheromone products. When female moths wish to seek out a mate, they produce a sex pheromone, a unique chemical signal that attracts males of the same species. Pheromone monitoring products perfectly replicate this signal, attracting male moths just as a genuine female moth would.

Historically, the Indian meal moth pheromone has primarily been used for monitoring purposes. With pheromone traps and lures, the pheromone lure will emit a concentrated signal to males, attracting them to a sticky trap where pest management professionals can later count them to inform on pest prevalence, locality, timing, and many more important data points. Suterra offers pheromone traps and lures for Indian meal moth and other stored product moths here.

However, pheromones are now being adopted and used in large commercial settings not solely to monitor the pest but to reduce pest pressure overall, via a process called mating disruption. Mating disruption works by dispersing a large amounts of the female’s sex pheromone into the facility’s air, rendering males unable to find females and, therefore, unable to reproduce during their short lifespan. The ambient pheromone is non-toxic and leaves no residue, making it safe to use in organic facilities.

Suterra’s Puffer IMM is unique in the stored product pheromone control category because, unlike hanging dispensers, the Puffer is an aerosol emitter. Unlike dispensers, the Puffer will always emit a consistent amount of pheromone that is not dependent on climate conditions. It lasts 6 months and, due to the broad area in a warehouse that a single Puffer can cover, takes very little time to install, making it cost- and labor-efficient compared to other pheromone products.

If you have questions about Indian meal moth, stored product pests, or mating disruption, the experts at Suterra are happy to help. Contact your local sales representative or send us a message on our website here.