Stored Product Pest and Pantry Beetle Damage and Management

Stored Product Pest and Pantry Beetle Damage and Management

DAMAGE
Pantry pests damage food by contaminating it with their bodies and their by-products. The larval stage of the Indianmeal moth produces frass (excrement) and webbing, and some beetle larvae produce secretions that give food a disagreeable odor and taste. Setae (hairs) from the warehouse beetle can irritate the mouth, throat, and stomach of people who eat infested products. In addition, pantry pests might introduce microbes into the food that could produce mycotoxins (highly carcinogenic compounds), especially if the food is stored in warm, humid conditions.

MANAGEMENT
Getting rid of food-infesting moths or beetles takes continuous, persistent effort if the infestation has been present for a while. Some pests are capable of living for many weeks without food, thus the threat of reinfestation exists until they die off or are killed. Follow the guidelines for removing and cleaning up an infestation. It is best, at least for several months after eliminating the infested products, to store any susceptible food in airtight containers or in a refrigerator or freezer. Also, as a general practice, storing infrequently used food items (e.g., pancake flour, grains, spices, etc.) in the freezer prevents infestations from developing.

Pheromone traps are available in many retail stores to monitor and trap Indianmeal moths. Insecticides are not recommended.

Detection
If you find small moths or beetles crawling or flying around your kitchen, look for the food source of these pests and remove it immediately. If you locate the infestation before it spreads to other packages, control may be relatively easy. The source is commonly a package damaged at the store or an opened one that is little used or forgotten. The best thing to do with the package is seal it up and dispose of it, removing it from the house immediately.

Cleaning Up an Infestation
Most commonly, by the time the insects are noticed they have already spread to other food packages. Carefully inspect all packages, especially those that have been opened or are exposed. Destroy any that give the slightest indication of infestation. Other than the insects themselves, telltale signs include webbing in tight places of a package or tiny holes in the container. Insects are less likely to invade packages that have their original seal, but more commonly infest those that have been opened or that have been on the shelf for a long time. Before replacing noninfested packages, wash shelves with soap and water, and scrub corners and crevices or vacuum them with a crevice attachment to remove eggs and pupae.

Pheromone Traps
Of the major pantry pests, pheromone traps are only readily available in retail stores for the Indianmeal moth. Pheromone traps for the Indianmeal moth will not attract beetles.

Use pheromone traps after the source of the infestation has been removed to detect moths that remain in the house. Pheromones are chemicals (in this case a sex attractant) produced by an organism to affect the behavior of other members of the same species. The sex pheromone attracts adult male moths into the trap where they get stuck on the sticky sides; these traps will not attract the female moths, but may reduce their ability to produce eggs if they catch males before they can mate.

Place the traps in the area of a previous infestation and check them weekly. Most traps remain effective for about 3 months. Whenever you catch a new batch of moths in traps, it is time to inspect packages again.



UC ANR Publication 7452