Misted nursery plot a tool in fighting wheat, barley scab

Managing Editor

BELTSVILLE, Md. (April 19, 2016) — Tucked away in a corner of the Central Maryland Research and Education Center’s Beltsville facility, several dozen small grains varieties are about to be put to the test under harsh disease conditions.
In about two weeks, researchers at the University of Delaware and University of Maryland will sprinkle disease-laden corn kernels on tiny plots of wheat and barley at the Central Maryland Research and Education Center hoping for infection of Fusarium head blight or scab, which has hampered small grains in the Mid-Atlantic in recent years.
Along with the infected corn as inoculum, the “misted scab nursery” is outfitted with irrigation to spray a fine mist overhead to give the disease an even better chance to proliferate.
“Basically it’s a worse case scenario,” said Dr. Jason Wight, field and variety trials coordinator for the University of Maryland. “We try to replicate what a farmer might do in the field up until the high amount of disease pressure. The uniqueness of this is having all these varieties in one place stacked against each other head to head.”
Some 57 wheat varieties and eight barley varieties from several seed companies were entered into the misted nursery trial. It also includes four experimental varieties developed by Dr. Jose Costa, USDA-Agriculture Research Service small grains breeder, for scab resistance and a few check varieties with documented resistance or susceptibility.
As the plots mature under the misting conditions, Wight and University of Delaware Extension plant pathologist Dr. Nathan Kleczewski, will gather field data and visual observations on the how well the varieties fare but also send harvested grain samples to the USDA’s Soft Wheat Quality Laboratory in Wooster, Ohio for analysis of vomitoxin, which is primarily associated with scab and other measures of baking quality.
Wight said they will also send samples from three of the five sites in Maryland’s state wheat trial that will add to the amount of data and show how the varieties performed in different weather environments.
“It’s a big favor to us,” Wight said of the USDA lab accepting samples. “We could have about 200 samples so that is going to be a lot to process.”
While the nursery in Maryland is reestablished after a short hiatus, according to Wight, misted small grains nurseries aren’t new to the region. While at the University of Maryland, Costa conducted one for more than a decade as part of his research in scab-resistance and Virginia Tech small grains breeder Dr. Carl Griffey also conducts one.
But after many recent years of extended wet periods pulling down small grains quality, identifying scab-resistant varieties suitable for the region remains an important issue and Wight said the collaboration between Maryland and Delaware will be one more source helping farmers choose what to plant in future years.
“Fusarium head blight or scab is of utmost economic importance to almost every wheat grower there is,” said Tom Mullineaux, president of the Maryland Crop Improvement Association, which helped to fund the project for two years along with the Maryland Grain Producers Utilization Board, the U.S. Wheat and Barley Scab Initiative and entry fees from seed companies. “This will be non-biased information we can provide to help growers make decisions as to which varieties offer the best protection.”
The recent grain quality issues have meant discounts for farmers at elevators and area grain buyers have to hold poor quality wheat longer as it’s blended with better wheat to meet end user specifications. Food safety concerns also have many bakers and other end users tightening quality specifications which puts more pressure on farmers to control for diseases like scab.
Speaking to farmers this winter at Delaware Agriculture Week, Kleczewski said planting varieties rated with “moderate resistance” can significantly impact vomitoxin levels.
“Resistance matters,” Kleczewski said. “Resistance is the most economical means in reducing our vomitoxin and headscab.”
The vomitoxin spores can travel several miles, Wight added, and still cause infection and widen its spread and impact.
Timely fungicide application is another part of controlling for scab, Kleczewski said at the winter meeting, and urged growers to use the Fusarium Head Blight Prediction Center at which tries to predict the risk of scab infection in the eastern United States with real weather data as a tool in making decisions on application.
Data collected from the nursery and lab analysis will be distributed to the funding organizations and presented at meetings and conferences in the region, Wight said. The misted nursery is funded through 2017 but Wight said he hopes it can be sustained longer. “We’d like to continue it and see it carried out over a longer period,” he said. “There’s always new varieties that need to be evaluated.”