Corn Earworm Monitoring – Moving Forward

It is likely that blacklight trapping will not be continued in the Rutgers Vegetable IPM Program beginning in 2025, due to the unavailability of the specific bulb that has been the standard for blacklight traps for decades.  Under these circumstances, the IPM Program will rely on pheromone trapping to determine levels of important crop pests such as the corn earworm (CEW).

The 30” Hartstack trap (see photo at right by K. Albright of Purdue Univ.), also called the Texas pheromone trap (TPT), which is used in the Rutgers IPM Program, as well as many insect monitoring programs in other states, is the best tool for determining spray intervals on silking sweet corn to limit CEW injury.  A number of New Jersey sweet corn growers already have one or more TPTs on the farm, but we encourage all growers of this crop to obtain at least one.

Deploying Traps

The TPT is mounted on ½” rebar set at a height of approximately 4’.  The trap is baited with one Hercon Luretape Corn Earworm Lure, available from Great Lakes IPM®.  An additional lure is added every two weeks, and the trap should always be deployed directly adjacent to sweet corn expressing fresh silks.  This means that the trap should be moved frequently during the season.

Building or Buying Traps

The TPT is relatively simple to manufacture, and the University of Kentucky has posted the plans and parts list for making these traps in the growers’ shops.  The UKy site for trap design is:  https://entomology.ca.uky.edu/ef010

For those who wish to purchase this trap rather than making their own, TPTs are available from Mike “O” Olsowski in Geneva, NY.  Mr. Olsowski has made a number of TPT tops for the Rutgers IPM Program and is willing to make and ship these traps to New Jersey growers.  Contact information for Mike “O” Olsowski :

Mike “O” Olsowski

3510 Sutton Rd.

Geneva, NY  14456

Phone:  315-651-5929

Recording Catches

Current silk spray intervals based on corn earworm catches in the 30″ Hartstack trap were developed by the Univ. of Delaware some time ago, and are represented on the following chart, which may be printed and posted in a convenient site on the farm so that growers can record the catch and determine a silk spray schedule.  This trap record also includes spaces for other insects for which commercial pheromones are available, including beet armyworm and fall armyworm.  Contact information for Rutgers Vegetable IPM Program staff (currently, Amanda Quadrel) is also included on the chart.

Sweet Corn

Corn earworm (CEW) moth captures from northern and central blacklight and pheromone traps continued to decrease  with an extended period of cooler night temperatures.   Pheromone trap information is available from all northern and central sites, but is limited  from southern New Jersey.  With little information from South Jersey, growers there would be wise to assume numbers at least as high as those represented in the central and northern traps.  Should night time temperatures rebound, we should expect increases in CEW catch from both trap types.  We will use a combination of pheromone and blacklight trap types to derive silk spray schedules by region.  Silking corn is at risk of CEW infestation at this time.  Be sure to access information from this publication in the upcoming weeks to determine how frequently you should treat silking sweet corn to protect it from CEW infestation.

The highest nightly blacklight trap catches of CEW for the week ending 9/18/24 are as follows:

The highest nightly pheromone trap catches of CEW for the week ending 9/18/24 are as follows:

Thanks to Joe LaForest of Univ. of GA, and the Southern IPM Center for producing maps from our NJ CEW data!

Using our current pheromone- based thresholds (30″ Hartstack trap) developed by the Univ. of Delaware, nightly corn earworm moth catches translate to:

0 moths – 6-7 day spray schedule

1 moth – 5 day spray schedule

2-20 moths – 4 day spray schedule

>20 moths – 3 day spray schedule

Silking Spray Schedules*:
South – 3 days

Central – 3-4 days

North – 3-4 days

*These recommendations are based on regional catches.  Adhere to tighter spray schedules if indicated by local trap catches.  Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn, or for fall armyworm (FAW) management at any stage.  Control with these materials is very inconsistent.

Beet Armyworm

Beet armyworm (BAW) numbers in pheromone traps in the Woodstown area of Salem County have dropped over the past week, but remain relatively high.  Thanks to a grower cooperator in that area, we know that catches range from 31 – 67/night over the past week in local traps.  This pest can cause significant injury on peppers as well as leafy greens like swiss chard, and kale.  Larvae are beginning to appear as far north as Hunterdon County, although it is likely that serious infestations are or will occur in southern NJ now.  Monitor pepper fields weekly for signs of feeding.  BAW larvae (photo at left) feed in the developing foliage in terminal growth of pepper plants.  Initially, leaves are skeletonized, but as larvae grow, they will move onto fruit and damage these as well.   In northern NJ, BAW is an occasional, and typically low level pest of cole crops.  Infestations tend to be very local for unknown reasons.  As with other armyworms, BAW is difficult to control with pyrethroid insecticides.  Effective materials include spinosyns (IRAC 5) and diamides (IRAC 28).

Corn Earworm Traps – 30″ Hartstack type

Growers wishing to purchase corn earworm pheromone traps to conduct their own on-farm monitoring should contact:

Mike “O” Olsowski

3510 Sutton Rd.

Geneva, NY  14456

Phone:  315-651-5929

Mike O manufactures these 30″ Hartstack traps in his shop.  These traps are the same as the ones we use currently in the IPM Program, and spray thresholds are based on this type.

Lures currently used in the Rutgers Vegetable IPM Program corn earworm pheromone traps are:

Hercon Luretape, available from Great Lakes IPM

Lures are placed in the clip at the base of the large cone, and a new one is added at two week intervals.

Welcome!

The Vegetable IPM Program welcomes Amanda Quadrel as the new Program Coordinator for southern New Jersey!  Amanda received her MS. from our Rutgers Entomology Department, working with spotted wing drosophila.  She has an excellent background in IPM tactics, and is currently meeting with growers and becoming familiar with some of our activities (though very late in the season) in the field.  Welcome, Amanda and good luck!