Stored product pests – a term coined by humans
By Austin M. Frishman, Ph.D.
Think outside of the box and consider these situations when attempting to eliminate stored product pests:
- The product and/or locations these insects are found in—or on—is often not where they are breeding.
- Flying insects like cigarette and drugstore beetles may emerge from a food source and fly to lights in another room or section of a warehouse. They hit the lights and feign death, fall down and land on whatever is below.
- Crawling insects like sawtoothed grain beetles crawl away from infested products, particularly after the products become heavily infested. If on shelves, these insects crawl to the edges and fall down. Stored products located in suspended ceilings create this problem.
- Sometimes the stored product harboring the insect is no longer used as stored food. For example, it can be hidden as a product in bean bags, a decoration on a Christmas tree or a collage on a wall. Look for these items when cabinets show no sign of these insects.
- Domestic rodents, deer mice and squirrels transport food items and rodent bait away from their original location. Once hidden in wall voids, chimneys and cabinet drawers, the material remains undetected and unused, and is eventually found by stored product pests. You may have to open a wall to reach the infested product.
- The problem with lumping insects into a simple category such as “stored product pests” is that insects can’t be classified as one dimensional. Insects such as Trogoderma (cabinet beetles) will readily feed on dead insects in insect light traps, paper wasp nests and dead honey bee nests left in walls. Just because a stored product pest is what you are searching for does not mean it is anywhere near a stored product.
- When a new house is inundated with a stored product pest, start to look outside. Here are two examples from my experience:
- The first situation involved mealworms crawling by the hundreds at ground level and upstairs. A nightly inspection revealed the larvae were crawling in from landfills to fill in the new lawn, and whatever was used was loaded with mealworms.
- The second situation involved sawtoothed grain beetles crawling in almost every room in the house. The beetles were found in straw and were placed over new grass seed. Again, just because we call some insects “stored product pests” does not mean they are always associated with the pantry.
- The use of conventional pesticides is off limits when stored grain pests appear in food for humans or animal consumption, and the product has to be destroyed in many situations.
Let’s look at some non-pesticide approaches to limit or eliminate an infestation from occurring.
Early detection helps, and when used with pheromone trapping, it is possible to knock out Indian meal moths.
This prevents new insects from invading and keeps eggs and larvae from developing.
Whether in a house or a warehouse, first in and first out (FIFO) should be the rule of thumb. Items required to sit for long periods (longer than the insect’s life cycle) require more diligent inspections.
This is my own coined word for designing structures and man-made items so one can clean them easily. The culprit is often the crack and cervices where food is hidden. For example, peanuts under a couch pillow or flour inside an electrical box all need inspections because the arcopestology is not adequate.
Proper screens and closed exit doors
If you open your doors, the insects will come. Heat, odor and air currents all help insects successfully get indoors.
When humans stopped continually migrating and started building structures and growing their own food, grain pests settled in. We are not about to regress to all migrating again, so we may as well be diligent and minimize the invasion of these pests.
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