The Indian meal moth: A dangerous pest in warehouses and homes

The Indian meal moth (Plodia interpunctella), also known as the food or kitchen moth, is a common pest in food warehouses, shops and homes. They mainly feed on dry food products such as flour, groats, bran or dried mushrooms, contaminating them and causing serious losses.

Anatomy of the granary weevil

The granary weevil is a nocturnal moth belonging to the family of weevils, characterised by two pairs of wings. The front pair of wings has a characteristic yellow and brick-red colouring with grey-blue stripes, while the rear pair is grey-brown or grey-blue. The wingspan is between 14 and 22 mm. The females lay white eggs with a diameter of 0.4-0.6 mm, from which larvae with a white body and a brown head emerge, changing colour depending on the food they eat. The pupa is about 7 mm long and brown.

Development cycle of the warehouse moth

Female warehouse moths lay an average of around 200 eggs, although under favourable conditions there can be up to 500. The eggs are laid directly on dry food products, so that the larvae can start feeding immediately after hatching after 8-10 days. The larval stage consists of 5 developmental phases and can last between 13 and 288 days, depending on the conditions in the room.

The way of life of the food moth

The warehouse moth can go into diapause, a period of developmental arrest and slowing down of life processes in unfavourable conditions. Under normal conditions, an adult lives for about 14 days and is active at night. The larvae feed on the sticky threads, which collect loose products in groups. An interesting fact is that the granary weevil can bite through polyethylene film up to 0.7 mm thick.

Occurrence and damage

The warehouse moth can be found all over the world and is the most dangerous storage pest in the USA. In Poland, it is very common and appears in warehouses, shops, utility rooms and apartments. By feeding on food products, the granary weevil contaminates them, which often leads to them having to be thrown away or used as bird feed, causing significant financial losses.

Control of the granary weevil

Various methods are used to combat the European grain borer, including chemical agents, infrared and ultraviolet rays, as well as heating rooms to temperatures above 50°C and freezing them to -15°C. One effective method of pest control is the fumigation of grain, which effectively eliminates larvae and adults. However, prevention and regular disinfestation of food storage areas such as warehouses and granaries are crucial to effectively counteract infestations of this pest.

The warehouse beetle is a serious threat to stored food. Controlling it requires not only the use of appropriate measures, but also consistent preventive actions to minimise losses and maintain the hygiene of food storage.