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

Trending Articles

InsecticidesNew Research Study Shows The Value Of Neonics
October 29, 2014
The study evaluated seed treatment, soil and foliar uses of neonicotinoid insecticides in the U.S. and Canada. Read More
Crop InputsPlatform Specialty Products To Acquire Arysta LifeScience
October 20, 2014
Once the acquisition is complete, Platform Specialty Products will combine Arysta LifeScience with previously acquired companies Agriphar and Chemtura Crop Solutions. Read More
Seed/BiotechMonsanto Offers New Support For Ferguson, Area Communities
October 8, 2014
Monsanto Co. has committed $1 million in new support for several collaborative efforts in Ferguson, MO, and surrounding communities in North St. Louis County. Read More
Seed/BiotechUnapproved Genetically Modified Wheat Found In Montana
October 3, 2014
USDA reports that one year after discovery of Monsanto's unapproved wheat in a single Oregon field disrupted U.S. wheat export sales, the GMO wheat has again been found in Montana. Read More
Equipment2014 Product Of The Year Voting
September 19, 2014
The deadline to vote for the 2014 CropLife IRON Product of the Year is October 31. Please cast your vote today to help us determine the winner. Read More
FertilizerFall Fertility 2014: Forecasting Fertilizer Use
September 7, 2014
Great crops this year have tapped the soil, and fall work is definitely called for, but how challenging will that get? Read More

Latest News

StewardshipTFI Recognizes Michigan, Maryland Farms For 4R Stewards…
October 31, 2014
As farming practices increasingly attract interest from the general public, two farmers are ensuring they meet public approval. Read More
Eric SfiligojBig Brother Is Already Watching
October 31, 2014
Opponents to UAVs seem to think they could be used to spy on other people. But spying is already taking place, through the Internet. Read More
StewardshipAsmark Institute’s New Training Center Focused On…
October 31, 2014
The newly dedicated Ford B. West Center for Responsible Agriculture will be used as a national training and education center for professionals in the ag input industry. Read More
StewardshipCTIC Tour Dives Deep Into Everglades
October 31, 2014
The most recent Conservation In Action Tour (CTIC) hit South Florida recently to tour the Everglades Agricultural Area. Read More
StewardshipResponsibleAg Begins Auditor Training
October 31, 2014
ResponsibleAg auditor training is now underway at the Ford B. West Center for Responsible Agriculture in Owensboro, KY. Read More
CropLife 100ValueAct Buys Stake In Fertilizer Dealer Agrium
October 30, 2014
ValueAct has bought 8.2 million shares in Calgary, Alberta-based Agrium, making them the second largest investor in the fertilizer dealer. Read More
InsecticidesNew Research Study Shows The Value Of Neonics
October 29, 2014
The study evaluated seed treatment, soil and foliar uses of neonicotinoid insecticides in the U.S. and Canada. Read More
StewardshipUSDA To Provide $4 Million For Honey Bee Habitat
October 29, 2014
Agriculture Secretary Tom Vilsack announced today that more than $4 million in technical and financial assistance will be provided to Read More
Crop InputsValent Launches New Low VOC ProGibb LV Plus Plant Growt…
October 29, 2014
ProGibb LV Plus PGR is a high-potency, liquid gibberellic acid formulation designed to comply with California’s new air quality standards for high volatile organic compound agricultural products. Read More
Crop InputsBayer CropScience Acquires Certain DuPont Crop Protecti…
October 29, 2014
Bayer CropScience and DuPont Crop Protection have signed an agreement for Bayer to purchase certain DuPont Crop Protection Land Management assets in the U.S., Canada, Mexico, Australia and New Zealand. Read More
ManagementWest Central Names New President
October 29, 2014
West Central’s board of directors have announced their unanimous decision to name Milan Kucerak President and CEO-elect following Jeff Stroburg’s retirement at the end of the fiscal year. Read More
InsecticidesValent U.S.A., MGK Form Marketing Agreement
October 24, 2014
Valent has formed an agreement with Minneapolis-based MGK to manage the marketing and sales of MGK’s crop protection line of insect control products within the U.S. beginning April 1, 2015. Read More
StewardshipFlorida’s 4R Advocate Keeps Improving
October 24, 2014
Florida farmer Alan Jones uses the 4R principles of nutrient stewardship as the core of his fertility program, which allows him to maximize production and keep costs in check. Read More
Seed/BiotechMonsanto Named One Of The World’s Best Multinational …
October 23, 2014
Monsanto ranked No. 8 in the world’s largest annual study of workplace excellence that identifies the top 25 best multinational companies in terms of workplace culture. Read More
Crop InputsArysta Hires Former Agri-Chem, CPS Employee For Delta S…
October 23, 2014
New Territory Sales Manager Mark Peel’s primary role will focus on working with growers regarding fungicides in Louisiana, Mississippi, Arkansas and Tennessee. Read More
CropLife 100GROWMARK Announces Appointments In Plant Food Division
October 22, 2014
GROWMARK, Inc. has announced the three key staff changes in its Plant Food Division. Read More
CropLife 100GROWMARK Appoints New VP Of Finance And Risk Management
October 22, 2014
Wade Mittelstadt has been named GROWMARK Vice President, Financial and Risk Mangement, effective December 1, 2014. Read More
FungicidesEPA Approves BASF In-Furrow Corn Fungicide
October 22, 2014
Field trials show Xanthion In-furrow fungicide provides more rapid emergence, extended residual control and improved seedling health than untreated crops. Read More