Indianmeal Moth - Pest Status and Pest Control

Pest Status and Pest Control

The Indianmeal Moth larvae can infest a wide range of dry foodstuffs of vegetable origin, such as cereal, bread, pasta, rice, couscous, flour, spices or dried fruits and nuts. More unusual recorded foods include chocolate and cocoa beans, coffee substitute, cookies, dried mangelwurzel, and even the toxic seeds of Jimsonweed (Datura stramonium). The food they infest will often seem to be webbed together.

After larvae or moths have been found, it is important to throw out all food sources that are not in very tightly sealed containers. The moths are able to get into surprisingly tight spots, including sealed bags by chewing through them. They are also notoriously difficult to get rid of, and can crawl on ceilings and spin cocoons in rooms other than the kitchen or pantry where they hatched. Last instar larvae are able to travel significant distances before they pupate. Pantry moth spray and insecticides made with essential oils and natural ingredients are a good alternative to chemical pesticides when using around food and pets, and can repel the moths from coming back. Use the pantry moth spray on all cupboard and pantry surfaces before returning the food items. When seeking the source of an infestation, the search thus cannot be limited to the immediate area where pupae are discovered.

None of the stages of the organism (eggs, larvae, adults) is very temperature-tolerant and all can be killed by a week of freezing or by brief heating in a microwave or conventional oven when such treatment is practical.

Nontoxic traps are also available to inhibit the development of adult moths and precipitate their destruction. For example, one type of trap is a triangular box with a lure inside and sticky walls. These traps are generally known as pheromone traps. In this case male moths are attracted inside by the female pheromone (the lure) and then get stuck against the sticky walls inside of the box.

Moths often do not even need a lure, as common glue traps sometimes work well to reduce the number of adults.

However, the efficiency of such traps is highly doubtful as they only capture males, and usually only a fraction of these, while adult females, eggs and larvae are unaffected, enabling a possible reinfestation. Thus it is recommended to first eliminate the source of infestation followed by larvae, eggs and eventual moths in the environment.

The caterpillars are parasitized by Bracon hebetor, a braconid wasp which is a potential biological control agent.