Fields help farmers fight fungus
By Tom Hallman
The fertile, rolling fields of Lexington County have sustained farm families for generations. Many of these fields yield the succulent strawberries that are a staple of spring and summer in the South.
Until now, though, the fields rarely talked back to their farmers.
At least one Lexington County strawberry field is doing just that. And if Clemson Extension agent Powell Smith has his way, more will follow, because what those fields have to say can save farmers a bundle of money.
“Deciding when to spray fungicides is not always an easy call,” Smith explains. “You don’t want to spray unnecessarily, but you don’t want to let the problem go untreated either. The better information the farmer has, the better decision he can make.”
The fields themselves can provide much of that information – if they’re equipped to do so. That’s why Smith engaged the help of strawberry farmer Mike Keisler in a research project that stretches from Lexington across the Southeast.
Keisler allowed Clemson scientists to erect a compact weather station perched atop a metal post in one of his fields. “Mike donated one acre to spray based on what the weather station tells him. The rest of the field he sprays as he always has,” Smith said.
Solar-powered and Internet-enabled, the station can monitor and report conditions in the field that favor the development of gray mold, a scourge of strawberries. It measures wind speed, temperature, humidity and the amount of solar radiation. It also detects leaf moisture, an essential condition for the disease.
A wi-fi connection uploads the data to computers at Clemson, where it falls under the watchful eye of Guido Schnabel, an Extension plant pathologist and state specialist for fruit diseases.
“The goal is to reduce the number of applications needed to fight diseases,” Schnabel said. “In a normal year, we’re able to reduce it by 50 percent.”
Keisler’s results were even better. In a year in which he would’ve made 14 fungicide applications, the research plot required only four.
The research ultimately may benefit farms and crops across the country, but it’s particularly important here and now, Smith said.
Gray mold is caused by a fungus whose scientific name, Botrytis cinerea, stems from the ancient Greek word for grapes, on whose moisture it has fed since time immemorial. But it can be especially serious and damaging to soft fruits like strawberries.
That’s anathema to Smith, who knows that strawberries are a high-value crop for small farmers in the Midlands. The second most valuable fruit crop in South Carolina behind peaches, strawberries here are grown overwhelmingly for fresh consumption – mostly on patches of just two acres.
“With strawberries, you get started early in the spring and generate cash flow that will help farmers finance the rest of the crop year,” Smith said.
As much as farmers depend on the research and advice of Clemson agriculture professionals, Clemson depends on farmers like Keisler, Smith said.
“In 18 of 20 years I’ve been here, he’s had a test plot on this farm,” Smith said. “We depend on the farm operators. And they trust this kind of research – performed in a field they know.”
The research is part of a regional project based at the University of Florida and funded by a USDA National Institute of Food and Agriculture grant.
Its benefit extends beyond saving individual farmers money on sprays. In the long run the research may be even more important to the nation’s strawberry crop as a whole. That’s because, over time, some diseases of strawberries have become resistant to the very chemicals farmers use to control them.
“There are seven different classes of chemical and each chemical class has several products,” Schnabel said. “There’s not a single class where we don’t have a resistance problem.”
As part of the research, Schnabel and his colleagues have developed a kit that enables farmers to determine the level of fungicide resistance they face.
“It’s very important the grower knows what still works in his location,” Schnabel said. “In four days we can tell the grower if there is a resistance problem and tell which of the classes of pesticide will work best for them.
“Ultimately, we want to use fewer sprays and more effective sprays – to spray less, and spray the right thing.”
Learn more about Clemson Extension horticulture programs:
See video and interviews with Powell Smith & Mike Keisler:
Watch video of Guido Schnabel’s profile kit: