Though Quiet, Rust Still Relevant

Three years after soybean rust first arrived in the U.S., it has yet to become the disease problem many had feared. But a University of Kentucky (UK) plant pathologist says it is acting as expected.

“We’ve not been crying wolf,” says Don Hershman, plant pathologist with the UK College of Agriculture. “It takes a while for the disease to build up, and eventually conditions will come together. I doubt if it’s going to happen every year. Will it be a one-in-five-year thing or a one-in-10-year thing? There’s really no way to predict that. You just have to be tuned in and be ready to act when needed.”

Standing Sentry

Rust can cause extensive crop damage but can be successfully treated with timely fungicide applications. Timely applications depend on finding the disease and monitoring its progression into the soybean growing areas from the southern U.S., where it overwinters on kudzu. Hershman notes there are more than 12 million acres of kudzu in this country, primarily in the South.

“We are noticing that rust seems to be moving north earlier and earlier every year,” he says. “Part of that is because pathologists have learned more about how to scout for it.”

A sentinel network of soybean and kudzu plots from Mexico to Canada are intensively checked from late winter until the end of the growing season. Pathologists have been successful in identifying the disease and giving early warning through this system. Most of the finds are on leaves taken from the field to a laboratory for incubation and microscopic evaluation.

“We are having more rust finds with each passing year,” Hershman says. “In 2005, we had 40 finds and 239 in 2007. Part of that is because kudzu is becoming more uniformly infected. We are also finding that long distance spore movement is very common, and that’s the scary part.”

The spores can be lifted and sent for miles during weather events, but these spores also have to survive the trip and then find receptive conditions in order to multiply. Large spore movement does not require a major weather event, such as a tropical storm or hurricane, but can move northward on normal weather patterns. So far spores have found their way into soybean growing areas and infected plants too late in the season to impact the crop. But Hershman says as the disease develops and overwinters in the larger areas of the South, more spores will be available to move earlier in the growing season.

Defense Planning Easier

Pathologists have found that producers have more time to spray than initially thought once the disease has been discovered. They have also been able to predict locations where the disease may pop up using three models that consider spore locations, spore movement, and weather conditions. These models were used to successfully predict a soybean rust infection in Iowa in 2007.

“It’s always about two and a half to three weeks from the time it is predicted until it shows up,” Hershman says.

This helps prepare growers for the potential arrival of the disease and allows them time to spray fungicides to control its spread. Timely findings of the disease and the use of prediction models can help to ameliorate the disease’s impact. Such tools give growers information to determine when and if they need to use fungicides to protect their crop.

“The best defense is a good offense,” he says. “We’ve had three years now, and we’ve seen three different patterns. The first year it went up the east coast. The second year it went up the east coast and through Kentucky, and this year it bypassed Kentucky and went up through Nebraska.

“The key for a producer is to watch the seasonal weather trends and monitor rust detections, especially in the Deep South, from May through July,” he adds. “Obviously, the earlier anything begins to happen the worse off we are going to be — the later, the better.”

Retailers and growers can visit www.sbrusa.net to monitor Asian soybean rust and soybean aphids this season.

Leave a Reply

Latest News
Acceleron B-300 seed coating
Crop InputsThe BioAg Alliance Launches New Yield-Boosting Microbia…
December 5, 2016
As part of their commitment to develop and commercialize innovative microbial solutions for farmers through The BioAg Alliance, Monsanto Co. Read More
ManagementCorn and soy planting update; Takeaways from Climate Co…
December 2, 2016
AgriBusiness Global Editor Dave Frabotta Joins Paul Schrimpf for a discussion of global corn and soybean planting trends, and a Read More
Radish cover crop taproot
Crop InputsSoil Health Institute, Datu Research Receive Grant To E…
December 1, 2016
The Soil Health Institute (SHI) and Datu Research has announced a $626,000 grant from the Walton Family Foundation to quantify Read More
Mike Stern
Precision AgClimate Corp. CEO Talks Retailer Support For Digital Ag
December 1, 2016
CropLife Magazine’s sister publication, AgriBusiness Global, recently sat down with Mike Stern, CEO of The Climate Corp., following the Monsanto subsidiary’s Read More
ManagementAg Industry Comes Together To Address Climate Change
December 1, 2016
Addressing climate change — and more specifically, decreasing greenhouse gas emissions from agriculture — can only be achieved through collective Read More
Young soybean field
HerbicidesLiquid Formulation Valor EZ Herbicide Available For 201…
December 1, 2016
Valent U.S.A. Corp. has released Valor EZ; a liquid formulation of the company’s leading herbicide, Valor. Named Valor EZ Herbicide Read More
Key Cooperative Marcus Construction Steel Building
ManagementThe Value Of Cooperatives In Modern Agriculture
December 1, 2016
Editor’s Note: Jaxon Mullinnix of  Lone Tree, IA, was recently named the Iowa state winner of the 2017 GROWMARK essay Read More
AGCO Operator of the Year Tony Kornder
SprayersAGCO Names Tony Kornder Operator Of The Year
December 1, 2016
AGCO Corp. names Tony Kornder with Genesis Growing Solutions in Le Sueur, MN, the 11th annual Operator of the Year. Read More
Chris Henney OABA
ManagementOABA Industry Conference To Provide Outlook For Future …
November 29, 2016
The upcoming Ohio AgriBusiness Association Industry Conference is packed with widely-respected speakers and industry professionals, sharing their expertise on a Read More
Corn
InsecticidesMajor Review Finds Neonic Poses Low Risk To Aquatic Inv…
November 28, 2016
A major new ecotoxicological review and risk assessment has been published in the peer-reviewed literature and concluded that registered crop Read More
EquipmentGSI Details New Grain Drying Efficiency System for Coop…
November 28, 2016
Grain elevators and ag co-ops are always looking for ways to increase their energy efficiency to help improve profitability. For Read More
Precision AgTrimble Debuts End-to-End FMIS Platform
November 28, 2016
October’s inaugural PrecisionAg Vision Conference left this author with many thoughts and things to ponder in the coming months. Probably Read More
AGCO AgControl system
Precision AgPrecision Ag Technology: Rate Control For The Times
November 28, 2016
It’s not surprising that the need for more economical, effective application is driving the demand for the latest rate controllers Read More
ARA
Eric SfiligojTaking The Industry’s Pulse At ARA
November 28, 2016
When most of you read this particular column, many of the industry’s key folks will probably be spending at least Read More
CHS Primeland
CropLife 100The 2016 CropLife 100 Report: Reviewing The Many Bulls …
November 28, 2016
For virtually all of 2016, the nation was wholly focused on the big Presidential election. Some folks aligned themselves with Read More
FertilizerNutrient Management, Conservation Among Topics Covered …
November 23, 2016
Certified crop advisers, consultants, farmers, agribusiness professionals and students will learn more about nutrient management, soil and water conservation, pest Read More
Monsanto sign
Crop InputsMissouri Governor Meets With Bayer CEO To Discuss Monsa…
November 21, 2016
Missouri Gov. Jay Nixon visited Bayer AG global headquarters in Leverkusen, Germany, on November 18 to discuss the proposed Bayer-Monsanto Read More
Arysta LifeScience
Crop InputsArysta LifeScience Forms Alliance With Beem Biologics
November 21, 2016
As part of its recently announced strategy to become a leader in high-value, high-growth specialty market segments in the crop Read More