By Scout Nelson
Aster Yellows phytoplasma is a plant disease that affects many flowers, vegetables, field crops, and weeds throughout the Great Plains. The disease is commonly found in purple coneflowers, but it can also infect onions, lettuce, carrots, potatoes, wheat, canola, zinnias, blanket flowers, cosmos, and many other plants. South Dakota State University Extension is expanding research to better understand where the disease occurs and how it spreads across the region.
Madalyn Shires, Assistant Professor & SDSU Extension Plant Pathology Specialist, together with Cody Molnar, is leading efforts to improve monitoring of Aster Yellows and encourages gardeners and farmers to help identify infected plants. Their work is supported through funding from the North Central Integrated Pest Management Center to strengthen disease tracking and improve future management strategies.
Aster Yellows is caused by a phytoplasma, a tiny plant pathogen that spreads through feeding leafhoppers. These insects move from plant to plant, allowing the disease to spread over long distances. Once infected, plants often develop unusual growth patterns instead of growing normally.
Common symptoms include yellow leaves, twisted stems, excessive branching known as witches' broom, poor flower development, distorted fruits, and reduced plant growth. In vegetables such as onions, carrots, and lettuce, infected plants may become misshapen and lose their market quality. Similar symptoms may also appear in important field crops and common weeds.
Researchers are asking the public to help monitor the disease by scouting gardens, landscapes, farms, and other growing areas. While coneflowers are frequently affected, researchers are especially interested in finding infections in other plant species. Public participation will help improve disease distribution, maps, and support future research.
Anyone who suspects Aster Yellows can submit plant samples for free testing through the special research project. Stems and leaves from affected plants should be collected, placed in a plastic bag with dry paper towels, kept refrigerated, and shipped as quickly as possible. Shipping early in the week helps maintain sample quality.
Photo Credit: pexels-olga-divnaya
Categories: South Dakota, Crops