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Mullen's Musings™

The Results Are In On Pheromone-Baited Traps


By Dr. Mike Mullen

Pheromone-baited traps are widely used to monitor for insect pests and, if you use them, it is important to know that you are not alone. Recently, I conducted a survey of 3,000 individuals in various aspects of the food industry to ask if and how they used traps to monitor for pests. About 400 responded. The survey was sent to representatives of the food processing industry, warehouse managers, packagers, bulk storage managers and retail outlets. In this column I will tell you how they answered my questions.


The breakdown of responders that use traps was as follows:

Processing 39%
Warehouse 27%
Packaging 19%
Bulk storage 13%
Retail outlets 2%

The respondents stored or sold baked goods, ingredients, flour, confections, pet foods, and unspecified products.

Ninety-five percent of respondents had at least occasional insect problems. Major insect problems were:

Indianmeal moth 26%
Red or confused flour beetle 19%
Warehouse beetle 19%
Cigarette beetle 16%
Sawtoothed grain beetle 10%

Eighty-four percent of those with insect problems use traps to monitor for the following pests:

Indianmeal moth 45%
Red and confused flour beetle 21%
Warehouse beetle 10%
Cigarette beetle 5%
Sawtoothed grain beetle 5%
Others 40%

Moth traps accounted for 56% of the traps and 41% were beetle traps. The other insects monitored for were generally cockroaches.

Traps were considered to be effective by 92% of the users. Most (64%) used them to monitor insect populations, 10% felt they controlled pests, 4% used traps to identify pests, and 2% felt that the traps prevented insects from attacking food products. Most (98%) felt that traps provided useful information and 93% felt comfortable using the information. When asked why, 84% felt that trap catch was a good indication of insect activity.

Consistency over time was used to judge how well traps worked by 49% of respondents. Only 19% thought that high numbers were important and 17% found that consistency between traps was important.

I believe that the responses show that trap catch is misunderstood by many of the users. Trap catch should be expected to vary between locations in a facility and increasing numbers could indicate a developing infestation that warrants further investigation and possible management action.

Traps were placed within a facility in a number of locations including:
Storage areas 36%
Where insects are generally observed 23%
Regular grid pattern 17%
Near machinery 5%
Break rooms 5%
Processing equipment 5%
Other places 9%

All of these locations are useful monitoring sites.

It was encouraging to find that 87% of respondents changed lures as often as recommended and traps were checked:
Weekly 60%
Daily 17%
Biweekly 15%
Monthly 9%
Rarely 1%

Regardless, traps should be checked at a minimum of weekly during summer and warm months, as well as, traps in warm and/or heated areas.


An overwhelming number of users (92%) believe that insects in traps are easy to count, but 62% felt they were difficult to remove from traps. Dust fouling the traps was a problem for 26% of the users with another 48% having occasional problems. However, to reduce dust problems only 26% of those using pitfall traps cleaned them. Trap users (82%) felt that the manufacturers provided adequate instructions for trap use and 89% felt that traps were easy to use.

In sticky traps, the insects can be marked with a felt-tip marker so that they are not counted at the next inspection. Of course sticky traps fouled with large numbers of insect or dust should be replaced.

One of the stickiest issues (pardon the pun) was about the price of the traps. Only 33% thought that the price of trap was too high with the remainder feeling that the price was about right. However, the desire for multiple species traps, even if slightly less expensive, was only favored by 33% of those responding.

When asked about expectations from trapping, 66% wanted an early warning system that would alert them to the presence of insects, 11% wanted to use trap data to determine treatment schedules and 11% felt traps could be used as a control. Of the remainder, 11% felt that pheromone-baited traps were just another tool and 0.3% felt that they have no use.

When asked what information that they actually get from trapping, 51% said they used the information to make pest management decisions, 49% used the trap data as an indicator of insects and the remaining 0.5% felt they got no useful information.

Most users (78%) said that they did compare the data from recent trap catches to make pest management decisions. The majority (92%) of users felt that using pheromone-baited traps improved pest control in their facilities. As a general opinion of pheromone trapping, 85% rated traps use as good, 13% as fair and 2% as either of little or no use.

Several of the responders had comments about trap use. These comments were:
Pheromone traps provide very useful information
Traps are a good tool to monitor the environment after controls have been implemented
We use pheromone trap numbers to see if we have to fog that particular area
An excellent IPM tool
Pheromone traps are used in all aspects of our food plant operations
The only way we know that we have moths is by increased numbers in the traps
Once insects are detected we can prevent them from spreading throughout the facility
Useful tool to eliminate recurring pest problems
Pheromone traps can direct sanitation's attention to the problem area
With the removal of pesticides from the market, pheromone traps are a great tool to use with IPM
Pheromone traps are another tool to make IPM programs better
Pheromone traps provide me with useful and workable information
Traps are an indicator of a problem
Pheromone traps give me a good idea of what I am working with
Use roach traps and baits that work really well

Several interesting points were made by the respondents to this survey:
•The use of traps is widespread and the information gathered from them is put to good use.
•The most important insect is the Indianmeal moth.
•The major weakness was the need for a better understanding of how to interpret trap catch. While most users understand that increased numbers means more insects and that controls may be needed.
•Much of the information that trap catch can provide is often overlooked. As an example, trap catch can be used to construct contour maps of a facility that can not only pinpoint insect problems, but show how these problems can increase and spread over time. The same maps can be used to show how well insect control procedures have worked. These issues will be discussed in a future column.


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