A newly identified disease affecting corn and sorghum is causing symptoms that closely mimic iron deficiency, potentially leading farmers to apply costly nutrient treatments that fail to address the underlying issue. Recent research published in Plant Health Progress documents the discovery and identification of a bacterial pathogen responsible for these symptoms.
The study, led by Ken Obasa of the Texas A&M AgriLife Research and Extension Center and Dennis Coker of Texas A&M AgriLife Extension Services, began in 2023 when bright lemon-green foliar discoloration with interveinal chlorosis was observed on wild grasses in the northwestern Texas Panhandle. The same symptoms later appeared in nearby corn and sorghum fields, affecting plant growth and development. In severe cases, plants failed to reach the reproductive stage.
Misdiagnosis and Economic Implications
Initial observations suggested iron deficiency; however, soil and plant tissue tests revealed that symptomatic plants actually had higher iron content than healthy-looking ones. The random distribution of affected plants within fields pointed to a biological cause rather than a nutrient issue.
“Given the similarity of the disease symptoms to those typically associated with iron deficiency, it’s not hard to imagine farmers spending extra money to apply supplemental iron, but sadly, only to find out it did not address the underlying issue,” Obasa stated.
After ruling out fungal pathogens and exploring the possibility of phytoplasmas, researchers identified the bacterial pathogen Pantoea agglomerans through specialized media, microscopy, antibiotic testing, and DNA sequencing.
Uncovering a New Pathogen
This research describes a previously unreported disease affecting corn and sorghum and suggests unusual biological behavior in the bacterium, including dimorphism and a possible distinct genotype of P. agglomerans. The findings are expected to inform agronomists to exercise caution and undertake testing of symptomatic plants before recommending the application of supplemental iron.
“Lack of awareness could result in unnecessary increases in production costs with no commensurate return on the additional investments,” Obasa emphasized.
Although the pathogen was first observed in the Texas Panhandle, its identification as a pathogen infecting corn and sorghum has significant cost-saving implications for farmers both domestically and internationally. Researchers are continuing to investigate how the pathogen spreads in the field, which will help guide the development of future disease management recommendations.
Broader Implications and Future Research
The announcement comes as the agricultural sector faces increasing challenges from climate change and evolving pest pressures. Understanding new diseases like the one caused by Pantoea agglomerans is crucial for developing effective management strategies and ensuring crop resilience.
According to experts, the discovery of such pathogens underscores the importance of ongoing research and innovation in plant health. The study’s findings could potentially lead to new methodologies for diagnosing and managing bacterial diseases in crops, which are vital for maintaining food security.
Meanwhile, the agricultural community is encouraged to stay informed about the latest research developments and to adopt integrated pest management practices that consider both biological and environmental factors.
For more detailed insights, readers can refer to the full study titled “Pantoea-Induced Interveinal Chlorosis (PIC): A New Bacterial Disease of Corn and Sorghum Caused by Pantoea agglomerans Identified in the Texas Panhandle,” available in Plant Health Progress. This peer-reviewed journal, published by The American Phytopathological Society, has been providing new scientific information to enhance the health, management, and production of economically important crops since 2000.
