Weather Conducive To Wheat Head Scab, Corn Armyworms

Last week, wheat fields in Barton County were scouted by Wyatt Miller, an agronomy assistant with University of Missouri Extension.

“The majority of wheat scouted this week was in the flowering stage. Some fields have just begun to flower, while in others, flowering is complete,” said Miller.

Miller says producers should be scouting their fields to determine if pesticide applications may be warranted. Current weather conditions have slowed the growth of wheat and may be conducive for head scab if wet weather continues.

Wheat is most susceptible to head scab at flowering. Head scab is favored by temperature range of 77-86° F, frequent rains, overcast days, and high humidity.

“Head scab is treated by using a preventative measure of a fungicide application. Producers should consider yield potential, future weather, and growth stage when considering fungicide application,” said Miller. “Once flowering is completed, head scab treatment will not be justified. If fungal diseases reach the leaf just below the flag leaf, fungicide application may still be appropriate.”

Wheat producers should also be scouting for true armyworms. True armyworm populations have been light in wheat this spring, but a few fields have required an insecticide application.

According to MU Entomologist, Wayne Bailey, economic thresholds are met when an average of four or more half-grown or larger worms per square foot are present during late spring and before more than 2 to 3% of seed heads are cut from stems.

“Although foliage feeding always occurs with true armyworm larvae, cutting of wheat heads from plants occurs only in some years,” said Miller. “No head cutting has been reported, but wheat should be monitored several times per week after heading as true armyworm larvae can cut most heads from plants in a two to three day period once they begin cutting heads.”

Very small larvae are pale green in color, but quickly change to yellowish-brown or tan bodies with tan to brown heads mottled with darker brown patterns. Three distinct broad, longitudinal dark stripes run the length of the body with one occurring on the back and one running down each side. Also one or more orange lines can be found running the length of each side of the body from head to tail.

To determine the presence of small larvae, scout plant debris on the ground and for feeding damage on lower plant foliage. Small larvae are best scouted during late afternoon, evening , and early morning hours. As larvae increase in size, they will feed during both night and day periods and move upward on host plants as they consume foliage.

Corn producers should be scouting fields for black cutworms and true armyworms. Black cutworm moths typically begin arriving in Missouri from southern states about April 1 with peak flights occurring about April 10 annually.

“While the risk of economic infestations in field corn is now reduced, it is still possible for moth flights to continue for several weeks and cause problems in corn,” said Miller.

The economic threshold for black cutworm in field corn is to treat when three-fourths of an inch or smaller larvae cause two to three percent or more of seedling plants to wilt or be cut above or below ground up to the 5-leaf stage of corn seedling growth.

“Black cutworm damage was seen in fields scouted this week and was reported to be above economic threshold levels in some fields in the area. True armyworm treatment in seedling corn is justified when 25% or more of plants are being damaged. True armyworm damage has not been seen yet in wheat or corn.”

Leave a Reply

Fungicides Stories
FungicidesSudden Death Syndrome, Brown Stem Rot Reported In Indiana Soybeans
September 3, 2014
Farmers and retailers should be watching for symptoms of these two diseases over the next few weeks as they are best managed through preventative methods. Read More
FungicidesResearchers Target Soybean Disease With Genetic Resistance Study
August 6, 2014
University of Illinois researchers will share new information on controlling sudden death syndrome through genetic resistance at this year's Agronomy Day. Read More
Soybean field
FungicidesValent Launches New Seed Protection Fungicide For Soybeans
July 16, 2014
The INTEGO SUITE System contains the first new, novel seed protection fungicide chemistry registered in 30 years by the EPA for protection against Pythium and Phytophthora. Read More
FungicidesNew Players May Make Pest Headlines In Corn, Soybean
April 1, 2014
The usual insects and diseases took a bit of a break in 2013, but other culprits surfaced — and could return. Read More
Top 100 Articles
Growmark Group
CropLife 100GROWMARK In 2015: Back, To The Future
March 2, 2015
The nation’s third largest ag retail organization is simultaneously moving forward while remembering its past. Read More
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
Latest News
Eric SfiligojCommodity Classic 2015: Playing The Waiting Game
March 2, 2015
There was plenty of future-talk at this year’s event as companies (and growers) are largely in a holding pattern of sorts. Read More
Industry NewsHighway Equipment Appoints New Director Of Business Dev…
March 2, 2015
Cory Venable, who joined Highway Equipment Company (HECO) in 2013 as OEM Account Manager, has been promoted to Director of Business Development. Read More
Prairieland FS employees
Eric SfiligojWorkforce Worries
March 2, 2015
Finding good employees almost always ranks as the No. 1 or No. 2 problem for ag retailers in our annual CropLife 100 survey. Read More
Growmark Group
CropLife 100GROWMARK In 2015: Back, To The Future
March 2, 2015
The nation’s third largest ag retail organization is simultaneously moving forward while remembering its past. Read More
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