Indian Meal Moth (Plodia interpunctella) Integrated Pest Management Plan
This document contains information about the biology and management of the Indian meal moth. A wide range of management options is listed. From this list, the IPM Practitioner can choose options to develop a unique management plan for each particular customer site.
Management Objectives for the Pest at the Particular Site What do you want/need to accomplish at the site in regard to the Indian meal moths? The answer to this question will vary, depending on the site and the customer. Some examples are:
- Eliminate complaints in the house or building and work with occupants to prevent future complaints.
- Work with homeowner or building manager to prevent future moth infestations.
- Help client comply with Health Department regulations.
Indian Meal Moth Identification
- Adults have a wingspan, from tip to tip, of about 5/8- 3/4 (16-20 mm).
- Wings are pale gray but the outer portion of the front wings are reddish brown with coppery scales.
- Larva are usually ½ inch long, white or off white but can also have a green, pink, or blue hue depending on its food.
- Larvae also have 5 pairs of prolegs on the abdomen, with each hook having one hook called a crochet.
Why Indian meal moths are considered pests
- Indian meal moths are the most common food-infesting moth found in homes, grocery stores, and any place with dried or stored food.
- They are general feeders upon grain and grain products, dried fruit and other stored food products.
- No diseases are associated with Indian meal moths.
Special Regulatory Conditions
California Health and Safety Code Sections that relate to beetles and cleanliness in food establishments:
114010. “All food shall be prepared, stored, displayed, dispensed, placed, transported, sold, and served as to be protected from dirt, vermin, unnecessary handling, droplet contamination, overhead leakage, or other contamination.”
114030. “A food facility shall at all times be so constructed, equipped, maintained, and operated as to prevent the entrance and harborage of animals, birds, and vermin, including, but not limited to, rodents and insects.”
114040. “The premises of each food facility shall be kept clean and free of litter, rubbish, and vermin.”
114050. “All food facilities and all equipment, utensils, and facilities shall be kept clean, fully operative, and in good repair.”
Article 11 Section 581 of the San Francisco Department of Public Health code states that: “No person shall have upon any premises or real property owned, occupied, or controlled by him or her, or it any public nuisance.”
Public health nuisances are defined as: Any noxious insect harborage or infestation including, but not limited to cockroaches, bed bugs, fleas, scabies, lice, spiders or other arachnids, houseflies, wasps and mosquitoes…”
Biology and Behavior of the Indian Meal Moth
To be successful, management strategies must take into consideration the biology and behavior of the Indian Meal Moth. Understanding the biology of a pest can reveal weaknesses and vulnerabilities that can be exploited when trying to manage the pest.
- Indian meal moths undergo a complete metamorphosis.
- Female Indian meal moths lay 100-400 eggs, usually at night.
- Eggs are laid singly, or in small groups, on or in their food supply and are roughly 0.3-0.5 mm in length.
- Eggs hatch after approximately 1-18 days.
- Larvae are on average 5/8 inch long and upon hatching will search for a suitable place to establish itself. Larvae will encase itself in a tunnel-like case of frass and silk woven together which it will feed in or near.
- The larval period lasts between 13-288 days depending heavily upon temperature and availability of food.
- Pupation will typically occur near the food source however, Indian meal moths have been known to crawl large distances before spinning their cocoons. Cracks, crevices, and wall-ceiling junctures are other favorite pupations sites of this moth.
- On average the Indian meal moth has between 4 and 6 generations per year with the average life cycle ranging from 25-135 days.
- Unlike the larvae, the adult Indian meal moth causes no damage to stored food products.
- The Indian meal moth are general feeders and consume a variety of grain products, dried fruit, seeds, nuts, graham crackers, powdered milk, biscuits, candies, chocolate, as well as dog food and bird seed.
- Dried fruit is a favorite for Indian grain moths and can be extremely destructive with this particular food source.
- Indian meal moths prefer the coarser grains and flour, such as whole wheat, but are able to successfully breed in food such as shelled or ear corn.
- Adults are attracted to light and will often be mistaken for clothes moths when flying.
- Indian meal moth larvae are also frequently misidentified as clothes larvae.
Factors that favor the Indian meal moth
- Poor sanitation, such as leaving spilled grains, cereals, and other foodstuffs, allows for sufficient food to maintain moth populations.
- Improperly stored food allows moths to easily infest packages and containers of foodstuffs.
Monitoring and Record Keeping
The purpose of monitoring is to track pest activity in order to catch small problems before they become overwhelming. Monitoring also makes it possible to properly time pest management actions and to evaluate the effectiveness of those actions. Records are kept to document the methods and products used and to record information that can be used to fine-tune pest management methods and plan future actions.
Visual inspection of likely infestation and breeding sites is the most useful monitoring technique.
The “tolerance level” is the number of Indian meal moths that triggers action to control the pest. The tolerance level is site-specific and differs depending on the customer, the location, and other factors. Determining the tolerance levels for a site helps prioritize work that must be done to control the pest.
Pests need food, water and shelter to survive. If even just one of these factors can be reduced (or eliminated), the environment will support lower pests and pests will be less likely to invade our living spaces.
To limit food and water availability
- Food preparation and eating areas should be thoroughly cleaned daily. Drain sinks and remove all food debris. Do not leave food prep and eating areas dirty over night.
- Discuss the importance of sanitation with the appropriate people.
- Periodically give all food preparation and storage areas a deep cleaning.
- Store food in the refrigerator, freezer, or cooler, or in moth-proof containers such as Tupperware or screw-top jars with a rubber gasket.
- Keep food and storage areas dry when not in use, especially over night.
- Keep storage areas well-organized and clean.
Physical controls employ physical means to remove grain beetles or prevent their movement within a structure.
- Clean storage and food preparation areas immediately after spills.
- Check grain, cereal, and other food packages for beetle infestations often. Inspection should include searching for cocoons in corners and cracks as well as on walls, behind items, such as picture frames, bookcases and desks.
- Use screw-top or tight fitting lids on food containers.
- In homes and food stores, infested packages are best discarded to prevent further infestation. Non infested food can also be frozen to prevent an infestation.
- Heat or cold can be used to control this pest in small quantities of infested food.
- Caulk or seal cracks or holes which may provide enter for beetles.
Pheromone traps have been very successful at trapping Indian meal moths. This particular trap only attracts males and is used to monitor activity during infestations. Pheromone traps can also be useful in capturing those moths that were overlooked during inspection.
The IPM Partnership
The PCO-Customer Partnership is Very Important
IPM works best when the customer and Pestec form a partnership to tackle the pest problem. Indian meal moths cannot be managed satisfactorily without the cooperation of the customer, especially in the area of sanitation. Pestec will discuss the findings of the initial inspection and any subsequent monitoring sessions with the customer to determine which issues and tasks will be the responsibility of Pestec and which will be the responsibility of the customer.
Information is a powerful tool in IPM. Information can help change people’s behavior, particularly in how they store food and dispose of waste. Changing these behaviors is often an invaluable part of managing Indian meal moths. Buildings occupants and homeowners can also help in the early detection of pests so that Pestec can be alerted before the problem is severe.
Pestec’s highly trained and knowledgeable staff can provide pest management education or training sessions for facilities managers, risk managers, building occupants, homeowner associations, and others.