Entomologists: Start Scouting Western Bean Cutworms

Corn growers should start scouting in late July for signs of Western bean cutworm, a potentially yield-reducing pest, two Purdue Extension entomologists say.

First found in Indiana in 2006, Western bean cutworms feed on corn, legumes and dry beans, such as kidney and black beans. Despite the name, they do not feed on soybeans.

The cutworms can be identified by the black rectangles that develop behind the head of the later instars. These are commonly found feeding within the ear in late summer.

Western bean cutworm populations are tracked and roughly estimated each year using pheromone traps placed throughout the state. The traps capture the grayish-white moths, which usually lay eggs on Indiana corn plants in July. Feeding damage can appear a few weeks later.

So far this year, moth captures in northern Indiana are lower than previous years, said John Obermeyer, Purdue Extension entomologist and Indiana trap coordinator. But the number of moth catches does not necessarily give entomologists an accurate number of larvae, and is generally used as a presence or absence tool to initiate scouting.

Larvae begin emergence after a period of warm weather, but extreme conditions, such as last year’s drought and excessive heat, are hard on Western bean cutworm. With the cooler, wet Indiana spring this year, Purdue Extension entomologist Christian Krupke said the insects are likely delayed.

“We’ve had a cool spring, so we’d expect emergence a little later than last year,” he said. “It is likely that the hot, dry weather that we had last year was not good for them.”

In the early stages of development, Western bean cutworms feed on pollen caught in leaf axils of corn plants (where the leaf meets the stem). This is when growers should apply insecticides to fields to prevent further damage. Once the cutworm is inside the husk of the corn plant and begins feeding on kernels, insecticides are no longer effective. When pollen is gone, kernel feeding will begin and continue until the first frost.

According to Krupke, western bean cutworms also are sometimes indirect pests because they can increase the risk of ear rot development in corn plants by feeding on corn kernels. Some ear rots produce toxins that can be fatal if consumed by livestock – especially swine.

“When you take your grain to the elevator, they will test for mycotoxins. If it is over the threshold for that particular toxin, they might reject the whole batch,” he said. “That’s why this insect is a concern, because it makes the fungal pathogen colonize the ear more fully, which in turn raises toxin levels.”

Some Bacillus thuringiensis, or Bt, corn hybrids are very effective in resisting western bean cutworm damage, but growers are urged to check the label of their particular hybrids. Scouting and insecticide sprays are effective as well, but must take place before larvae enter corn ears.

More information about Western bean cutworm scouting can be found here.

Leave a Reply

Insecticides Stories
InsecticidesHow To Scout For Corn Earworms In Corn
July 28, 2014
In her weekly report, University of Missouri Agronomy Specialist Jill Scheidt discusses what to look for when scouting for corn earworm. Read More
InsecticidesEPA Grants Besiege Insecticide Additional Approvals
June 18, 2014
EPA has granted additional registration approvals for the use of Syngenta's Besiege insecticide on sorghum, cereal grains and peanuts. Read More
InsecticidesPrevathon Insect Control Approved For Cereal Crops
January 13, 2014
DuPont's Prevathon insect control powered by Rynaxypyr has received U.S. EPA registration for use on cereal crops, including wheat, most other small grains and sorghum. Read More
InsecticidesInsecticides 2014: Insect Pressure, Solutions On The Rise
January 2, 2014
Bt resistance, weather concerns and myriad other issues have led to an increase in both traditional pest pressures as well as new pests. Read More
Top 100 Articles
CropLife 100Pinnacle Expands Sanders Brand In The South
February 27, 2015
Pinnacle has acquired Hopkins Seed and Chemical in Qulin, MO, which expands the company's Sanders brand to nine Southern states. Read More
CropLife 100Pinnacle Launches New Providence Agriculture Location In Indiana
February 27, 2015
Pinnacle Agriculture Holdings — ranked No. 6 on the CropLife 100 — has established a new retail location in New Castle, IN, which will operate as part of Pinnacle's Providence Agriculture brand. Read More
CropLife 100Cooperative CHS Returns $518 Million To Owners
February 23, 2015
The 2015 cash return to owners is based on CHS net income of $1.1 billion, the company's second highest on record. Read More
corn field
CropLife 100The Andersons’ Humic DG Now Available In Canada
February 13, 2015
The Andersons, Inc. Turf & Specialty Group has announced its Humic DG product is now available to customers in the Canadian turf, agriculture and horticulture markets. Read More
Farmer on tablet
CropLife 100Southern States Co-op: An Inside Look At Our Aerial Imagery Program
February 8, 2015
Now is as good a time as any to explore the basics of what a retail aerial imagery program looks like today. Read More
CropLife 100Wilbur-Ellis Inks Satellite Imagery Agreement
February 3, 2015
Wilbur-Ellis Company has reached an agreement with Planet Labs to bring satellite imagery to the AgVerdict software platform. Read More
Latest News
CropLife 100Pinnacle Expands Sanders Brand In The South
February 27, 2015
Pinnacle has acquired Hopkins Seed and Chemical in Qulin, MO, which expands the company's Sanders brand to nine Southern states. Read More
CropLife 100Pinnacle Launches New Providence Agriculture Location I…
February 27, 2015
Pinnacle Agriculture Holdings — ranked No. 6 on the CropLife 100 — has established a new retail location in New Castle, IN, which will operate as part of Pinnacle's Providence Agriculture brand. Read More
Management2,4-D Celebrates 70 Years; GROWMARK Uses Super Bowl Ad …
February 27, 2015
Jim Gray, executive director of the 2,4-D Research Task Force, lays out planned activities to mark the chemistry’s 70th anniversary. Read More
HerbicidesUniversity Of Arkansas Flag The Technology Program Adds…
February 27, 2015
Started in 2010, the Flag the Technology program provides a visual reference for applicators to distinguish between fields planted with different herbicide-tolerant trait technologies. Read More
Luckey Farmers, Inc.’s Berkey Farm Center
Industry NewsLuckey Farmers’ Berkey Branch Certified In 4R Nut…
February 26, 2015
The 4R Nutrient Stewardship Certification Program has announced Luckey Farmers Inc.’s Berkey Farm Center in northwest Ohio has been added to its growing list of nutrient service providers to achieve certified status. Read More
Crop InputsWinField Unveiling NutriVision Technology, Ascend Dry F…
February 24, 2015
New for 2015 are NutriVision Technology, a unique tool for monitoring in-season plant nutrient availability, and Ascend WSG plant growth regulator, a new dry formulation of Ascend plant growth regulator. Read More
FertilizerNew Formulation Of NutriSphere-N Protects High Volume U…
February 24, 2015
Verdesian Life Sciences is launching NutriSphere-N HVTM, a new polymer formulation of the proven NutriSphere-N Nitrogen Fertilizer Manager that protects high-volume applications of UAN. Read More
EquipmentIowa Ag Secretary Northey Names Hagie Water Quality Lea…
February 24, 2015
Iowa Secretary of Agriculture Bill Northey has named Hagie Mfg. as a recipient of the Secretary’s Water Quality Initiative (WQI) Leader Award. Read More
FungicidesEvito Fungicide Gives Canadian Wheat Growers New Diseas…
February 24, 2015
EVITO fungicide from Arysta LifeScience North America gives Canadian wheat and barley growers a new option for disease control. Read More
Eric SfiligojThe Commodity Classic Turns 20
February 23, 2015
Two decades in, this annual gathering of all things agriculture has become a must-see event. Read More
CropLife 100Cooperative CHS Returns $518 Million To Owners
February 23, 2015
The 2015 cash return to owners is based on CHS net income of $1.1 billion, the company's second highest on record. Read More
ManagementCropLife Retail Week: On The Road Edition
February 20, 2015
Editors Paul Schrimpf and Eric Sfiligoj discuss their recent trips to the National Farm Machinery Show in Louisville and the Read More
Crop InputsLand O’Lakes Acquires FLM+ Assets
February 19, 2015
FLM+ will become a wholly owned subsidiary of Land O'Lakes, Inc., and the company will retain its employee base after closing of the deal, which is scheduled for the second quarter of the year. Read More
Seed/BiotechUnited Suppliers, Stine Seed Form Marketing Alliance
February 19, 2015
The new alliance will greatly expand sales opportunities for Stine Seed with the United Supplier Seed Link Owners. Read More
Crop InputsVilsack To Deliver Commodity Classic Keynote Address
February 19, 2015
The secretary will deliver a keynote address to several thousand farmers and ag allies during the event's General Session, to be held Friday, February 27, in Phoenix, AZ. Read More
Crop InputsSoybean Storage Tips
February 19, 2015
On-farm storage of soybeans requires some special considerations compared to corn. Read More
Monsanto Sign
Crop InputsBioAg Alliance Delivers Promising Field Trial Results
February 19, 2015
In its first full year of field trials, the BioAg Alliance reported that the top 10 microbial strains tested in corn and soybeans showed very promising results. Read More
National Farm Machinery Show overview
EquipmentNational Farm Machinery Show Attendance Up By 16K
February 18, 2015
The 2015 event saw the second highest attendance total of all time as 310,589 attendees that included exhibitors and agribusiness professionals traveled to the Kentucky Exposition Center to participate in the nation’s largest indoor ag trade show. Read More