[Stored Product Pests] Flexibility is Key

Pheromone traps are effective tools for monitoring stored product pests, especially moths such as Indian meal moths and Mediterranean flour moths. Pheromone traps are often used in food warehouses and food-processing plants. Homeowners are increasingly using clothes moth pheromone traps. In warehouses, place traps in a grid pattern to pinpoint new infestations.

Vertical support beams are already in warehouses; use them to set a grid pattern. Many warehouses will have 40 feet by 40 feet or 60 feet by 60 feet bays established by their vertical support beams. Some warehouses do not have support beams, and in these cases, the pallet racking or other means can be used to secure a natural grid pattern. Many warehouses have fire extinguishers set evenly around the warehouse that will offer a clear site for a trap.

The size of the grid will vary with the size of the facility, but as a general rule, intervals of about every 50 feet produce good results. If an area seems to have an infestation, more traps should be placed around that location to help zero-in on the infested goods.

It is important to remember that pheromone traps are used to monitor for the presence or absence of pest insects. There is no set magic number regarding when to react. The key to interpreting pheromone trap captures is to look for population increases. When the weekly numbers show a significant increase from one week to another, additional action should be taken.
 

Placement.

Traps also should be placed near potential insect harborages, such as corners, beams, and new shipments of stored products. As a rule, place traps for flying insects at a height of 6 feet. Don’t place the traps near exterior doors and windows to avoid luring insects from outdoors. This is especially true for warehouse beetles.

A colored plastic ribbon placed around the vertical support beam containing a pheromone trap provides the pest manager an easy way to locate the traps in a large and crowded warehouse. Recording the weekly capture with electronic bar coding is a good way to accumulate useful information and show your customer a trending report on a monthly or quarterly basis.

The use of pheromone traps should not be limited to large food warehouses and food-processing facilities. They can be useful as well in smaller facilities such as restaurants, grocery stores, museums, health-food stores, pet stores, drugstores, and even private homes. “A few well-placed traps can be an early warning system to detect newly arrived infested goods and prevent infestations,” says Sandy Kraft of Pinto and Associates, an industry consulting firm.

It is recommended to place pheromone traps outdoors around the perimeter of a building containing stored products. The outdoor traps should contain Indian meal moth, warehouse beetle, and sometimes cigarette beetle pheromone lures. The lures last for about one month outside in the wind and sunshine. The sticky traps can fill up fast with debris and should be changed more often than indoor traps. The knowledge of outdoor populations will help you understand the outdoor pressures that occur when a dock door is opened, when moths fly in through obsolete roof vents, and when warehouse beetles may be in large numbers outdoors and biasing the trap results in your indoor traps.

Here, adjustments should be made to move or remove those traps close to external doors and vents. It is important to be flexible when starting a pheromone-trapping program. You must be prepared to move traps, add traps, and remove traps in a building being monitored.

The author is founder of Insects Limited, a pheromone manufacturer based in Westfield, Ind. He has been researching pheromones for more than 35 years.