Kentucky: Soybean Sudden Death Syndrome Showing Up

Soybean sudden death syndrome (SDS) caused by the root-rotting, soil-borne fungus Fusarium virguliforme, is beginning to show up in soybean fields across Kenturcky. To my knowledge, all of the sightings are in patches of plants or individual plants, and are not field-wide. SDS has been seen in Kentucky each year, to one degree or another, since 1985.

SDS is evident first in foliage where plants show yellow blotches between the veins.

Sometimes this this early symptom can look almost virus like. In most cases, blotches eventually coalesce and result in a yellow and brown discoloration between the veins, but the veins remain green. In severe cases, the leaflets will fall off, but the petioles will remain attached to the plant. Foliar symptoms are the result of a toxin produced by the fungus in diseased root tissue.

The foliar symptoms descibed above can look similar to stem canker, Dectes Stem Bore injury, and even pytotoxicity symptoms caused certain triazole fungicides, so foliar symptoms in and of themselves are not diagnostic for SDS. Additional symtoms include severely rotted roots (F. virguliforme is a root rot organism) and a light brown discoloration of the stem when sliced open with a knife. Healthy stems will appear a cream color. When all three symptoms are evident, you can be quite confident that you have made a field diagnosis of SDS.

This disease is poorly named in that the disease does not usually suddenly appear, nor is the end result always death. In fact, SDS foliar symptoms first appear much like other diseases, a little at a time. It is only “sudden” if you have not been looking. I have seen plants with SDS recover (put out leaves without characteristic foliar symptoms) and in most cases, the disease comes in too late, or does not impact enough of a field, to significantly reduce yields.

Severe foliar symptoms can be misleading and often do not indicate that the disease has or will significantly impact yields. In fact, I have seen many instances over the last 27 years where severe foliar symptoms developed across a field (late), but the yield retieved was a record for the field. So with SDS, when symptoms show up relative to crop stage is everything.

Fusarium virguliforme infects roots early in the season and foliar symptoms normally appear in the reproductive stages, as is the case in fields this year. Abundant soil mositure encourages SDS and that is why we are seeing more of the disease this year than we normally do. In a more typical year, a greater extent of SDS is often associated with very early planting; doublecrop beans are rarely affected. However, in a year like this one, planting date associations are blurred and we may find that the disease even ends up developing in doublecrop soybeans.

The best way to control SDS is to plant a resistant variety. They are not that hard to come by. But there is nothing you can do to slow or stop SDS once it is evident in a field. For sure, applying a fungicide WILL NOT HELP.

In summary, SDS often has a “bark” more hurtful than its “bite”. Twenty-seven years of experience in Kentucky has shown that people often get all worked up over SDS because of the hyped-up name for the disease and because symptoms usually show up late in the season in an otherwise good looking crop. However, the end result is commonly little or no measureable yield loss, unless the disease is widespread and severe in a field before pod fill is complete, which is rare in Kentucky.

Leave a Reply

Fungicides Stories

FungicidesSyngenta Launches New Seed Treatment Fungicide
May 22, 2017
Syngenta has announced the launch of PLENARIS seed treatment fungicide for the control of downy mildew in sunflower. PLENARIS contains Read More
Winter Wheat
FungicidesREGALIA Rx Available from Koch Agronomic Services for 2017 Crops
May 8, 2017
Koch Agronomic Services, LLC has announced that REGALIA Rx biofungicide is available for U.S. corn, wheat and soybean growers who Read More
Crop InputsBioSafe Systems Introduces PerCarb Broad-Spectrum Bactericide / Fungicide
April 26, 2017
BioSafe Systems announces PerCarb (Sodium Carbonate Peroxyhydrate), a new alternative to potassium bicarbonate and lime sulfur products for use in Read More
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
Trending Articles
Migrant farm workers
LegislationTrump: Immigration Crackdown Won’t Impact U.S. Agriculture
May 16, 2017
President Donald Trump said he would seek to keep his tough immigration enforcement policies from harming the U.S. farm industry Read More
AGCO Ratliff featured
Eric SfiligojRemembering Robert Ratliff
May 15, 2017
With all the fast-paced happenings in agriculture this spring, with multiple mergers in the works and planting season in full Read More
Case sprayer nozzle closeup
EquipmentSpray Application: A Nozzle Renaissance
May 2, 2017
If you had asked four-decade ag veteran Mark Bartel, President of Wilger Inc., just a few years ago what lay Read More
ManagementWashington Update, Dow-DuPont Earnings, and the Passing of an AGCO Legend
April 27, 2017
Editors Paul Schrimpf and Eric Sfiligoj talk about the latest Beltway news, crop protection company 1st quarter numbers, and the 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
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
Latest News
Eric SfiligojMonsanto ‘Picks Its Battles’ by Nixing Deere Deal
May 23, 2017
Having been in the trade journalism game since the mid-1980s, I remember several watershed moments during my career. One of Read More
FungicidesSyngenta Launches New Seed Treatment Fungicide
May 22, 2017
Syngenta has announced the launch of PLENARIS seed treatment fungicide for the control of downy mildew in sunflower. PLENARIS contains Read More
Corn close up
Crop InputsMonsanto’s First HPPD Herbicide Garners EPA Appro…
May 19, 2017
Monsanto announced today that EPA has federally approved Harness MAX Herbicide, the first herbicide in the Monsanto portfolio to provide Read More
ManagementPrecision Planting Deal, China Developments, and Enviro…
May 18, 2017
Editors Eric Sfiligoj and Dan Jacobs discuss the latest news on John Deere’s now dead deal for Precision Planting, China’s Read More
Soybean aphid leaf
InsecticidesMulti-state Research Reveals IPM Best Option for Treatm…
May 17, 2017
About 89.5 million acres of soybeans will be planted across the U.S. in 2017 — a record high, according to Read More
GROWMARK-2017-Interns
CropLife 100GROWMARK Names 2017 Summer Interns
May 16, 2017
Forty-two college students are exploring agricultural career opportunities this summer as GROWMARK interns. They are working at FS member cooperatives Read More
Migrant farm workers
LegislationTrump: Immigration Crackdown Won’t Impact U.S. Ag…
May 16, 2017
President Donald Trump said he would seek to keep his tough immigration enforcement policies from harming the U.S. farm industry Read More
Flooded corn in Indiana
FertilizerBoth Wet and Dry Conditions Threaten Nitrogen Loss
May 15, 2017
The weather is notoriously unpredictable, leading to challenges for planting, harvesting and applying the nitrogen (N) your corn crop needs. Read More
farmer Kip Tom
Precision AgAg Tech: On the Cusp of Something Big?
May 15, 2017
The investment and ag-tech sectors’ continuing courtship of agriculture, smoldering for three or four years now, was well in evidence at Read More
AGCO Ratliff featured
Eric SfiligojRemembering Robert Ratliff
May 15, 2017
With all the fast-paced happenings in agriculture this spring, with multiple mergers in the works and planting season in full Read More
Greg Musson, Gar Tootelian
ManagementOpinion: Shaking Your Perspective in Ag Retail
May 12, 2017
Some of you I’m sure have encountered our recently retired salesman extraordinaire, Dan Bellanger. He worked in the industry for Read More
Exterior view of CPS Big Lake facility which includes enclosed receiving and load out area
CropLife 100New Alternative Weed Resistance Traits Could Experience…
May 12, 2017
It wasn’t too many years ago that ag retailers and their grower-customers could hardly wait for new options to fight Read More
Diane Allemang and Dan Jacobs
Crop InputsFMC Agricultural Solutions, Casa Pacifica Partner to He…
May 11, 2017
FMC Agricultural Solutions is teaming up with Casa Pacifica Centers for Children and Families, an organization that supports vulnerable children Read More
UncategorizedWhat’s Up With ARA
May 11, 2017
CropLife Editor Eric Sfiligoj talks with Brian Reuwee regarding what issues are on the docket for the Agricultural Retailers Association. Read More
BASF Maglis tablet retailer grower
Precision AgQ&A: What BASF’s Latest Foray into Precision …
May 11, 2017
In late April, BASF agreed to acquire U.S. precision ag player ZedX, a leader in the development of agronomic weather, Read More
Pam Marrone
Crop InputsMarrone Bio Innovations Enters into Distribution Agreem…
May 11, 2017
Marrone Bio Innovations, Inc., a leading global provider of bio-based pest management and plant health products for the agriculture markets, Read More
Bayer
Crop InputsBayer to Sell Liberty Business to Seal Monsanto Deal
May 8, 2017
Bayer has agreed to sell its Liberty herbicide and LibertyLink-branded seeds businesses to win antitrust approval for its acquisition of Read More
Trump, Senate, Cabinet
LegislationTrump’s EPA Appointee Dismisses Half of Major Sci…
May 8, 2017
(Via NYTimes.com) EPA has dismissed at least five members of a major scientific review board, the latest signal of what Read More