James Miller, Associate Certified Entomologist from Trécé Incorporated, answers five questions about the control of stored product beetles.
Management of stored product pests in commercial situations requires ongoing monitoring with control programs implemented to keep numbers down as well as when an outbreak occurs. While many pest managers often think of moths as being the key stored product pest, especially in domestic situations, many species of beetle present a threat to the safety of stored products, particularly in commercial facilities.
Monitoring systems for the detection of stored product beetles are often underutilised. Yet, the monitoring of stored product beetles is a critical component of a facility’s pest management program. Here, James Miller, ACE (Associate Certified Entomologist), US market manager, PCO with Trécé Incorporated (pictured above) reviews the important aspects of monitoring food-infesting beetles within an IPM program, outlining what a stored product beetle monitoring program should look like.
1. What are the most important stored product beetles?
The most prolific stored product beetles are the red flour beetle, confused our beetle, cigarette beetle, warehouse beetle, drugstore beetle, sawtoothed grain beetle, and merchant grain beetle. Furthermore, stored pest ecology varies based on the product and environment in the facility; multiple species may be damaging goods at the same time. In addition to the beetles listed above, the rusty grain beetle, hairy fungus beetle, granary weevil, rice weevil, and lesser grain borer are common finds.
2. What attractants should be used in monitoring traps?
Monitoring systems and traps for stored products pests use semiochemicals (pheromones and kairomones) as attractants. Extensive research has found a synergistic response when both pheromones and kairomones are combined in a unique system for certain species. Many beetles have specific known pheromones, such as the aggregation pheromone used for red and confused our beetle monitoring systems. Other beetles, for which there are no commercial pheromones, have shown increased response to proprietary kairomone attractants.
3. What style of monitoring system is the most widely used?
Commonly used monitoring designs are adhesive styles – which are suspended from or placed on surfaces – and pitfall-style monitoring systems, which are used on the floor of a facility. They are designed to fit the species behaviour, for example, adhesive-based systems work well for cigarette and warehouse beetles because these beetles can fly. Pitfall systems work best for red and confused our beetles. The specific details of the trap designs, with the addition of specific attractants, should be meticulously planned to fit the biology of every species targeted for monitoring.
4. How are these monitors used?
Pest managers must first determine the species to target, then determine which style of monitor best suits the pests’ behaviour. Traditionally, monitors should be placed in grid-like patterns throughout areas known to harbour the pest or susceptible food product. Adhesive monitors should be hung 4-8 feet from the floor, and away from food contact zones. Pitfall monitors should be placed on the floor near racking/column footings, equipment legs and wall/floor junctions with care taken to ensure they are not trip and fall hazards. Spacing can range from 10-50 feet depending on the pheromone and kairomone lures being used.
5. How does the use of monitors benefit an IPM program?
Monitoring systems work in three ways. Firstly, they detect beetles, allowing the pest manager to identify the species. Secondly, they determine the number of beetles present and give an indication of population abundance. Usually some intervention with an insect pest control agent is necessary when the population abundance begins to increase considerably after early detection. Thirdly, they allow the pest manager to assess the actions taken and if necessary to modify their IPM approach.
When beetles are detected in the monitors, pest managers should record the number of target pests caught. Tracking the rise and fall in the number of pests over time allows for chemical control measures or use of pheromone disruption strategies to be taken at the correct time, ensuring the overall success of the IPM program.