To even the odds, scientists combined cultural practices that help frustrate the weeds' germination and growth. This means preparing a seedbed of soil in an unplanted peanut field, then later plowing the top 3 inches to control weeds before they become established. It could also prevent the need to increase peanut seeding rates. With a helping hand from science, smut could become the next weapon in the war on weeds. The smut fungus, Sphacelotheca holci , causes a disease that turns the weed's seed structures into a black, crumbly mass.
Scientists hope to encourage the microbe's mischief by formulating it into a mycoherbicide spray.
They're conducting field tests to evaluate the spray's potential as a natural alternative to conventional chemical herbicides. The chemicals help prevent Johnson grass from invading farm fields and outcompeting crop plants for space, sunlight, nutrients and water. But using herbicides is costly and raises environmental concerns. Scientists now are contemplating ways to boost the fungus' virulence, or ability to cause disease in the weed. That's what farmers could call a new chart that identifies 27 sedge species that are weeds of U.S. crops.