Penn State Extension


Instructions for Using Pheromone-Baited Traps for European Corn

During the past several years Pennsylvania has used pheromone lures to monitor the 3 "worm" pests of sweetcorn: European corn borer, corn earworm and the fall armyworm. Proper monitoring allows growers to increase spray frequency when populations are high and decrease spray frequency when populations are low. Using trap counts to adjust spray frequency results in fewer total sprays, offering benefits in terms of dollar savings on pesticide, reduced residues and time saved by not spraying.

A complete monitoring site will have one of each of the following traps:

  • Wire cone trap for European corn borer E strain. (also known as the New York strain)
  • Wire cone trap for European corn borer Z strain. (also known as the Iowa strain)
  • Wire cone trap for Corn earworm.
  • Bucket trap for the Fall Armyworm.

Using Pheromone Traps

Set up:

The wire cone traps are made from ¼" aluminum wire mesh. They get their name from the inverted cone shape. The wire cone trap is designed to sit upon a piece of rebar hammered into the ground. As their name implies bucket traps resemble a small water pail. These traps are available in all colors although research has suggested that tricolor (yellow, green and white) traps function the best for fall armyworm. The bucket traps are designed to hang from a wire trestle.


All traps should be located adjacent to corn fields and have about 5 feet of clearance around them. Traps baited for European corn borer should be near weeds.


Traps need to be properly labeled before inserting the pheromone lure. Some agents prefer to mark traps directly while others use detachable tags.

Changing Lures:

Traps need to have a fresh pheromone lure inserted every two weeks. Each lure is labeled ECBe European cornborer e-strain, ECBz European corn borer z-strain, CEW corn earworm or FAW fall armyworm. Be sure to use the correct lure in the appropriately labeled trap. Prior to use, pheromone lures should be stored in the refrigerator.

a. For wire cone traps (European corn borer-e and z strains, and the corn earworm) affix the pheromone lure to the small piece of guide wire at the center of the trap. The guide wire comes off the bolt on the main support arm. The lures for European corn borer have a column shape with small holes in both ends. The guide wire can be inserted into the smaller of these holes. In windy areas the lures may need to be secured with an alligator or document-binding clip. The fall armyworm lures are small flat strips. These lures will need to be affixed to the guide wire using a paperclip, alligator clip, or document-binding clip. Before completion, ensure that the lures are properly secure.

b. Bucket traps have a built in receptacle for storing the pheromone lure. This receptacle is covered with a small yellow cap. Remove the cap and insert the lure into the receptacle.


Traps need to be monitored every Monday and data reported by Monday afternoon. Empty the moths onto a clean flat surface and count. To avoid confusion it is best to completely finish counting one trap before starting another.

a. Wire cone traps: Unclip the two springs on either side of the containment canister. Lower the canister into a comfortable position and twist off the end cap. Invert the canister and distribute the contents onto a clean flat surface. Count and record the number of moths.

b. Bucket traps: disconnect the white bucket and gently invert the bucket onto a clean flat surface. Before counting inspect the moths for any non-target captures.

Checking the fall armyworm moths for any non-target captures:

Check the fall armyworm moth catch against the linked document to ensure that they are fall armyworm and not one of the look-a-like species. Armyworm Factsheet.

Reporting the Data:

It is important to report data promptly even if no moths are captured. A true zero is different than a no-report. A zero means that there are no moths. A no-report means that we don't know how many are present.

Contact Shelby Fleischer ( (814-863-7788) for specific infomation on reporting procedures

Data can be entered online at by clicking on the input data link on the sweetcorn monitoring site. Contact Shelby Fleischer to set up a password.

Length of the program:

Traps will be set out in late May and reporting begins in early June. The season will run for 17 weeks.

Getting your questions answered:

If you have any questions please contact Shelby Fleischer at 814-863-7788. Email:

This document is intended to be used as supplemental material for a training presentation.


Pesticides are poisonous. Read and follow directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams, or ponds.

Authored by: Shelby Fleischer, Professor

March 2002 Reviewed February 2004

Penn State College of Agricultural Sciences research, extension, and resident education programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.

Visit Penn State Extension on the web:

Where trade names appear, no discrimination is intended, and no endorsement by Penn State Cooperative Extension is implied.

This publication is available in alternative media on request.

Penn State is an equal opportunity, affirmative action employer, and is committed to providing employment opportunities to minorities, women, veterans, individuals with disabilities, and other protected groups. Nondiscrimination.

© The Pennsylvania State University 2019