An IPM approach to preventing IMM infestations

Indianmeal moth adult Photo: Dr. Mohammed El Damir, BCE

The Indianmeal moth (IMM) (Plodia interpunctella) is a common pest that infests stored food products worldwide (Kumar et al., 2017). This species is known for its distinctive gray color with two-toned wings as an adult and cream-colored body with brown heads as a larva (Stevens et al., 2018). These larvae can cause severe damage to stored food products by consuming them and contaminating them with their feces and webbing (Lacey et al., 2019).

Understanding the biology and habits of IMM can also help prevent and control infestations. IMM prefer to lay their eggs on food products stored for long periods and in warm, humid conditions (Stevens et al., 2018). Therefore, food handling and storage facilities should store products in cool, dry conditions to discourage IMM infestations.

IMM also have a high reproductive potential, with a female moth capable of laying up to 400 eggs in her lifetime (Kumar et al., 2017). These eggs hatch into larvae, which as aforementioned, can cause significant damage to stored food products. Therefore, prompt and effective monitoring and corrective measures are essential in preventing a small infestation from becoming a large-scale problem.

It is also important to note that IMM can infest various food products, including grains, nuts, dried fruits, pet food, and spices (Lacey et al., 2019). In addition, over the years, we have received many reports of Indianmeal moth infections of coffee beans. Therefore, food handling and storage facilities should be vigilant in inspecting all stored products, not just those most commonly infested.

The most effective way to control and prevent infestations of the IMM in food handling and storage facilities is by implementing an integrated pest management (IPM) approach. This approach involves identifying and removing infested food products, cleaning and sanitation of storage facilities, and use of traps and insecticides as necessary (Stevens et al., 2018). In addition, proper storage of food products is essential in preventing infestations. Storing food products in airtight containers and regularly checking stored products for signs of infestation, such as webbing, larvae, or adult moths, can help prevent infestations.

Indianmeal moth larvae Photo: Dr. Mohammed El Damir, BCE

To reduce the risk of infestation, food handling, and storage facilities should consider taking the following corrective actions:

• Regularly inspect food products: Regular inspection of food products can help identify infestations early on, allowing for prompt corrective action (Phillips et al., 2021).
• Implement proper storage practices: Storing food products in airtight containers can prevent adult moths from laying eggs on the food. Facilities should also ensure that stored products are not past their expiration date and are rotated on a first-in, first-out (FIFO) basis to prevent old products from becoming infested (Stevens et al., 2018).
• Maintain cleanliness: Regular cleaning and sanitation of storage facilities can help remove food debris and eliminate potential breeding sites for IMM (Stevens et al., 2018).
• To prevent IMM infestations in food handling and storage facilities, regular monitoring and the use of approved insecticides are essential. Pest management professionals and the facility’s pest management team should interpret trap catch and take appropriate corrective action if necessary, following all label instructions and using only approved insecticides.
• Pheromone-based trapping of male moths and insect light traps are effective methods for monitoring adult populations, and traps should be placed indoors and outdoors. During transit in delivery trucks, it is recommended to use pheromone traps and take samples from each pallet before storing them. When temperatures are at or above 60°F, IMM can be found living outdoors, and field studies in the USA have shown only one to three generations of IMM with distinct peaks or peaks during the summer months. Trapping for this pest around the outside of a stored-product warehouse can offer several advantages in an overall pest management strategy. The trap selected for outdoor trapping must be able to withstand the weather and should not be prone to becoming saturated with insects quickly (Stevens et al., 2018; Campbell and Arbogast, 2004; Doud and Phillips, 2000; Nansen et al., 2004; Phillips et al., 2021). Generally, in spring, the PMP will place IMM pheromone-baited traps on the outer perimeter of the storage facility. These traps should be inspected regularly to predict the arrival of indoor populations of this pest and prevent many from causing an infestation by applying perimeter treatments of a proven residual insecticide. Each outdoor trap should be numbered, flagged, and cross-marked on the facility’s map indicating the location, and trap counts should also be documented. Traps need to be replaced when their sticky surfaces become covered with moths or dust, or at 4-week intervals.
• Disturb mating: Mating disruption is a technique used to control IMM by releasing synthetic pheromones that interfere with the ability of male moths to locate and mate with female moths. This technique is widely used in commercial settings such as food processing facilities to prevent damage caused by the larval stage of IMMs. Studies have shown that even short-term exposure to mating disruption dispensers can significantly reduce mating activity in IMMs for the rest of the night. (Baker et al., 2016) The use of mating disruption can be an effective and environmentally friendly alternative to traditional insecticides.

The IMM is a significant pest of stored food products, causing damage and contamination. Implementing an integrated pest management approach and proper storage practices can help prevent and control infestations in food handling and storage facilities. Regular inspection of stored products, maintaining cleanliness, and using traps, mating disruption, and insecticides as necessary can all play a role in reducing the risk of infestation.

References:

• Baker, T. C., et al. “Mating disruption of Plodia interpunctella: threshold conditions for inhibition of male response to pheromone.” Entomologia Experimentalis et Applicata 159.1 (2016): 85-92.
• Campbell, J. F., & Arbogast, R. T. (2004). Distribution and abundance of stored-product insects in the United States: a synthesis of data from surveys, research programs, and infestation records. Journal of Stored Products Research, 40(1), 3-17.
• Doud, C. W., & Phillips, T. W. (2000). Rapid reinfestation of a flour mill after methyl bromide fumigation: sources of Tribolium castaneum and other arthropods. Journal of Economic Entomology, 93(5), 1576-1585.
• Kumar, R., Gupta, R., & Pandey, R. K. (2017). Indianmeal moth: An important pest of stored food products. Journal of Entomology and Zoology Studies, 5(6), 122-125.
• Lacey, L. A., Neven, L. G., & Headrick, H. L. (2019). Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae). In Capinera, J. L. (Ed.), Encyclopedia of Entomology (pp. 1-6). Springer.
• Nansen, C., Phillips, T. W., & Williams, H. J. (2004). Field evaluation of a pheromone trap for detecting Indianmeal moth (Lepidoptera: Pyralidae) in a wheat warehouse. Journal of Economic Entomology, 97(4), 1357-1363.
• Phillips, T. W., Burkholder, W. E., & Johnson, J. A. (2021). Indianmeal moth (Lepidoptera: Pyralidae) development on wheat-based diets with varying amounts of bran. Journal of Economic Entomology, 114(3), 1278-1283.
• Phillips, T. W., Throne, J. E., & Subramanyam, B. (2021). Stored-product entomology and arthropod contamination of food: An analysis of recent US FDA foodborne illness outbreak data. Journal of Stored Products Research, 92, 101787.
• Stevens, L., Rice, R. E., & Puppala, N. (2018). Indianmeal moth (Plodia interpunctella). University of Florida IFAS Extension. Retrieved from https://edis.ifas.ufl.edu/in893.
• Stevens, E. A., Fields, P. G., & White, N. D. (2018). Indianmeal moth (Lepidoptera: Pyralidae) management in food processing facilities. Journal of Integrated Pest Management, 9(1), 8.