Traps Monitor Insect Infestations

These tips can help make pheromones an effective tool in your pest-control program.

Scott Williams
By  Scott Williams , DTN Entomologist
Traps are insect-specific, so be sure to select the model that’s right for your pest, Image by Scott Williams

If you feel a breeze drift by you today, note that thousands of invisible “love letters” are streaming past. And, while tiny romance is in the air, it could spell heartache for your crops.

Most insects “see” the world through smell, using their antennae to sift out important scents. Some are pheromones that, like a love letter, connect members of a species over long distances. The receiver follows the pheromone trail upwind hoping to find a mate, but what they seek is not always what they find. Pheromone traps have turned what used to be a private correspondence into one of pest management’s cleverest tricks.

TRICKY TRAP. Pheromone traps (PTs) succeed on a principle of “false advertising.” By tricking insects into believing an amorous partner is inside, PTs attract a sample of the population. Pheromone lures make PTs species-specific, meaning you catch just the insects you want. Used well, PTs can make other pest-control methods (i.e., pesticides) more effective, reducing management costs and damage to crops.

Because of their specificity, picking the correct lure for your target pest is important. Fall armyworm will not be tempted by a corn earworm lure and vice versa. And, some species, such as European corn borer, will respond to entirely different lures, depending on the population. These strains (E or Z) will only respond to the corresponding pheromone and are mostly region-specific. It’s important to do your homework before buying a PT.

One downside of PTs’ specificity is that each trap only targets one pest at a time. Targeting multiple species with the same trap could make detection more difficult. Additionally, scouts may confuse similar-looking species that fly around the same time. It’s best to buy enough traps for all your pests.

USEFUL TIPS. When setting up your trapping program, reflect on your goal. For some species, such as Western bean cutworm, you may only be interested in when the season’s flight begins. This information will help you time the start of scouting for egg masses in the field. For corn earworm, you’ll want to check whether the number of moths caught in traps exceeds the pest’s economic threshold. Knowing in advance what type of information best serves your management program will help you determine the number of traps you need while saving you time later.

Next, pick a trap that’s right for your pest. Some insects have behaviors that limit which traps you can use (e.g., corn earworm flies up from below, making large funnel traps ideal but bucket traps less effective). Trap placement is also important. Adult European corn borer likes to rest on grassy vegetation around crop fields and won’t be in areas with bare ground. Set traps out before the insects are expected to appear. Once the trap is set, place the lure and label the trap with the lure’s and target pest’s name, and the date of placement.

Check traps weekly, and change lures as directed by the manufacturer. Handle lures with gloves, and avoid leaving contaminated materials around the trap. This will limit the number of objects competing with your traps for the insects’ attention. Be sure to wash your hands after handling baits to prevent cross-contamination.

Once insects arrive, it’s time to take a count of how many are present. You may find out just how attractive PTs are when you’re catching bugs by the hundreds. Be sure to remove them from the field so your next count is accurate.

For More Information:

You can find pheromone traps and species-specific lures at the following retailers:

Great Lakes IPM




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