Although the year-ending holidays are weeks away, now is the time to start preventing unwanted guests in the pantry, said a University of Illinois Extension horticulture educator.

"Many people think that pantry insects are coming into their homes via contaminated human food," said James Schuster. "Even though this happens occasionally, it is the least common way these insects get into the home. A more common way is on or in dried cat and dog food. However, pet food is still not the most common method by which these insects arrive.

"Most often, the different kinds of insects that are considered 'pantry insects' invade our homes through wild bird food." These insects, he pointed out, may be in the food as eggs, larvae, pupa, or even adults. The larvae and the adults may be feeding in the food. Eggs and pupa can be in the food or in or on the packaging material.

"Once the pantry insects are in the warm environment of your home, the life cycle often coincides so that the adults are emerging from Thanksgiving to New Years," he said. "Each successive generation is larger than its predecessor."

Birds do not mind eating the live insects and, in fact, the insects are probably more nutritious than the birdseed. "However, if you are a homeowner, you do not want these insects crawling and flying around the house," he said. "To help prevent this from happening, you should freeze the pet food or birdseed 24 hours from its arrival. If the food does not freeze in less than 24 hours, the insects will start developing alcohol and survive the freezing process."

If the freezing process was slow, the feed needs to be put in an airtight container and kept at room temperatures for at least two weeks so that the insects lose their alcohol. Once the insects are alcohol-free, re-freeze the food or birdseed quickly.

"No matter where you store the pet food or birdseed, keep it in an airtight container," he said. "If stored outside, consider using an airtight container in a steel garbage can that you can chain the lid onto. This helps keep raccoons and squirrels from eating through the airtight container and eating the food or birdseed."

If the insects are already flying or crawling, sanitation is the only recommended control. Contaminated human food should be discarded. All non-contaminated human food and any dried pet food should be frozen quickly and stored in airtight containers.

"Keep food stored in airtight containers for the next six months," Schuster said. "Open the containers only long enough to remove the necessary food. All cupboards, cracks, and crevices should be thoroughly washed with a strong soap and water solution

Source: James Schuster, Extension Educator, Horticulture, schuster@uiuc.edu

August 28, 2006