Dig Those Corn Rootworms

It’s a dirty job, but someone has to do it. In fact, entomologists are encouraging more growers and their retailers to dig corn roots this coming summer to look for signs of corn rootworm feeding.

“Digging roots when it’s hot outside and corn is pollinating usually isn’t something a person would choose to do,” says Kevin Steffey, entomologist with the University of Illinois. But with the increasing spread of western and northern corn rootworms to rotated corn, Steffey says it’s important to monitor what’s happening below ground.
“Corn rootworm is not a problem in every corn field in every year,” says Steffey. “But between extended diapause in northern corn rootworms and the variant western corn rootworm, pressure in first-year corn is spreading.”

That’s in addition to continuous corn rotations, where rootworm pressure is common in most areas of the Corn Belt. “Corn after corn is the crop sequence that the corn rootworm has made its living on for many years,” reminds Jon Tollefson, entomologist with Iowa State University.

Whether growing first-year or continuous corn, digging and rating roots isn’t just a good way to monitor root damage, “it’s the only way,” says Iowa State University entomologist Marlin Rice.

Lodging is probably the most obvious indicator of a rootworm problem, but it’s not a reliable one. “Lodging can have nothing to do with rootworm control,” says Rice. “You can have a strong wind take down your corn, especially in a wet field, and it won’t have anything to do with rootworm feeding.”

You can’t go by root ball size or stalk strength either, says Larry Bledsoe, entomologist with Purdue University. “Those are genetic factors that are largely determined by your hybrid,” he explains.

“What you’re looking for is signs of root feeding, and the only way to do that is to dig up roots and look at them — especially during mid to late July after most of the injury has occurred,” says Rice.

“If you suspect rootworm pressure or want to compare control methods, don’t wait until harvest to look at your roots,” advises Von Kaster, entomologist with Syngenta Seeds “It’s a hassle, but an in-season root dig will really give you the clearest picture of what’s happening in your fields.”

To help growers rate rootworm damage, Iowa State University has developed an interactive web site that illustrates degrees of root feeding damage based on a 0 to 3 scale. Visit www.ent.iastate.edu/pest/rootworm/ for information.
“There’s no magic number on the scale that definitively indicates when we reach the point of yield loss,” says Kaster. Soil moisture, root regeneration — even wind — can affect the extent of yield loss from root feeding.

When evaluating rootworm control methods, Kaster advises looking at root ratings from multiple sites. “That will give you a much broader view of insect control over a range of weather, soil and cultural conditions,” he explains. “For example, root ratings from Syngenta and university trials representing 57 site years in 2004- 07 demonstrate (Syngenta Seeds’) Agrisure RW is very consistent across locations, with an average root rating of 0.22.”

Entomologists agree that it’s important to look at a variety of results when evaluating any corn rootworm control method. Likewise, it’s important to monitor what’s happening below ground in your grower’s fields. Take a look at the ISU root ratings Web site this winter and make sure you’re out in those fields this summer with a strong shovel and a cold water bottle.
 

Leave a Reply

Insecticides Stories

Lygus pratensis
Crop InputsCalifornia Agriculture: What A Difference A Year Makes For Insect And Disease Control
April 3, 2017
“We finally got the rain,” David Haviland, Entomology and Pest Management Farm Advisor with the University of California Cooperative Extension, Read More
Golden Harvest Corn healthy leaves
Crop InputsFMC Emerges as DuPont Crop Protection Business Buyer, Becomes 5th Largest Ag Chemical Company
March 31, 2017
FMC Corp. and DuPont today announced the signing of a definitive agreement for FMC to acquire the portion of DuPont’s Read More
Soybean Closeup
FungicidesNew CROSSOVER PRO Formulation Offers Insect and Disease Control
March 29, 2017
INNVICTIS CROP CARE, LLC has launched CROSSOVER PRO as a first of its kind formulation combining propiconazole and lambda-cyhalothrin for Read More
Corn Field
InsecticidesArysta LifeScience, DuPont Collaborate On Rynaxpyr Premix Formulations
February 8, 2017
Arysta LifeScience recently announced that it has entered into a global collaboration with DuPont Crop Protection for the development of Read More
Trending Articles
Young Corn Plants
Crop NutritionStill Hunting Yields
April 1, 2017
There’s no denying it — the agricultural marketplace today is undergoing a fundamental shift in fortunes. Not too many years Read More
Nutrients for Life Foundation Teacher
FertilizerNutrients For Life Foundation Celebrates 10 Years Teaching Fertilizer Education
March 23, 2017
Those in agriculture know fertilizer is a vital ingredient to grow strong, productive crops. In fact, fertilizer is responsible for Read More
AdjuvantsA New Weed-Control Era Begins: But First, One Last Obstacle
March 4, 2017
There is trepidation, there is reluctance, and there is excitement. Ag retailers feel it all about the new dicamba and Read More
LIFT Academy video screenshot
Crop InputsLIFT Agriculture Academy: A Q&A With West Central Distribution’s Dean Hendrickson
March 1, 2017
West Central Distribution recently launched its LIFT Agriculture Academy, a new, premiere training and professional development resource for West Central’s ag Read More
Farmer and aptop
Matt Hopkins10 Warning Signs Your Website Is Grossly Outdated
February 8, 2017
Your Website is often a visitor’s first impression of your ag retail business. A positive first impression can set the Read More
AgriSync
Matt Hopkins17 Agriculture Apps That Will Help You Farm Smarter In 2017
December 9, 2016
Ag professionals are working smarter, not harder, than ever before. Smart farming technologies have enabled them to reduce costs, maximize Read More
Latest News
ManagementAn Inside Look at Award Winning Ag Retailer Gar Tooteli…
April 20, 2017
CropLife Editor Eric Sfiligoj discusses An Inside Look at Award Winning Ag Retailer Gar Tootelian Read More
Students Soybean Field
Industry NewsMACA Announces 2017 Young Leader Scholarship Recipients
April 19, 2017
The Mid America CropLife Association (MACA) Board of Directors selected 11 college students to receive the MACA Young Leader Scholarship Read More
Growmark FS Outlet
SoftwareKnoa Software Solution Helps GROWMARK Boost System Perf…
April 19, 2017
Knoa Software, a leading provider of user experience management (UEM) software, has announced that GROWMARK, Inc., a regional agricultural cooperative Read More
Crop InputsFBN Publishes ‘Voice of the Farmer’ Agricul…
April 17, 2017
Farmer’s Business Network (FBN) released today its “The Voice of the Farmer”, which the company is describing as “a special Read More
ManagementTalking Responsible Ag
April 13, 2017
CropLife Editor Eric Sfiligoj discusses the Responsible Ag program with director Bill Qualls. Read More
Crop InputsFlying Under the Radar No More, FMC Goes Big
April 13, 2017
Describing FMC as “under the radar,” admittedly, is probably a stretch. But in a snap of the fingers, FMC upped Read More
Crop InputsWhat do Roundup and Mickey Mouse Have in Common? Califo…
April 13, 2017
(SOURCE: East Valley Times) Glyphosate, the active ingredient in Monsanto Co.’s Roundup and many other weed killers, is being added Read More
Syngenta headquarters in Basel, Switzerland
Crop InputsSource: ChemChina to Divest Assets to Adama Following S…
April 11, 2017
China National Chemical Corp. plans to redistribute agrochemical assets to its Adama unit after the $43 billion takeover of Syngenta Read More
Farming drone air
Eric SfiligojThe Interest in UAVs for Agriculture Grows
April 10, 2017
At times, it seems as if experts have been predicting “big things” for unmanned aerial vehicles (UAVs) for several years Read More
OpinionOpinion: Taking On The Farmers Business Network
April 8, 2017
Well, another round of venture capital funding has come to Farmers Business Network (FBN), followed up with the obligatory feature Read More
Drone
EquipmentFarming Drones: The Future Of Agriculture?
April 7, 2017
Chances are, you already know drones are amazing. After all, this is something DroneLife readers just understand. But if you’re Read More
ManagementFMC-DuPont, Crop Plantings, and UAV Updates
April 6, 2017
Editors Eric Sfiligoj and Jackie Pucci discuss the purchase agreement between DuPont and FMC, the 2017 crop acreage mix and Read More
Falcon soil sampler
EquipmentSerious Soil Sampling Rigs
April 6, 2017
The industry has seen an increase in automation in sampling equipment, and consultants now often pull cores with an automated Read More
Iowa waterways
FertilizerDow AgroSciences Recognizes Ag Retailers’ Role in Prote…
April 6, 2017
The state of Iowa and its agriculture community have worked for decades to preserve soil health, protect water quality and Read More
Farmer Scouting Weeds in Soybean Field
EquipmentSoil, Scouting Programs Continue To Gain Value
April 5, 2017
How much growers and their retailers utilize soil testing and scouting varies greatly. But they should step up their game Read More
Forbes Mixing Bowl NYC
Precision Ag6 Key Takeaways from Forbes Mixing Bowl NYC
April 5, 2017
Advisory investment group The Mixing Bowl teamed up with Forbes for its New York-based event this year to discuss technology’s Read More
Pam Marrone
Crop InputsQ&A With Pam Marrone On The World’s First All-Biolo…
April 4, 2017
Marrone Bio Innovations Inc. and Israel-based Ground­work BioAg in February announced successful field trials of the world’s first all-biological comprehensive Read More
Corn soil
Crop NutritionBiostimulants Clamor For A Piece Of The Row Crop Market
April 3, 2017
The question these days isn’t who is venturing into biostimulants — it’s who isn’t. Or more to the point: The Read More