Hidden Cotton Virus Circulated for Nearly Two Decades Before Detection, Study Reveals.

A virus long thought to be a recent threat to U.S. cotton production has, in fact, been quietly infecting crops for nearly 20 years, according to new research. Scientists have found that cotton leafroll dwarf virus (CLRDV), officially reported in 2017, was present in the United States as early as 2006.

The discovery, published in the journal Plant Disease, is the result of a collaborative study led by researchers from the USDA Agricultural Research Service and Cornell University. The findings challenge previous assumptions about the virus's timeline and demonstrate the power of bioinformatics and public genetic databases in tracking plant pathogens.

“CLRDV was believed to be a recent arrival in the U.S.,” said Alejandro Olmedo-Velarde, a former Cornell postdoctoral researcher and now an assistant professor at Iowa State University. “But we detected evidence of the virus in archival cotton samples from Mississippi in 2006, Louisiana in 2015, and California in 2018—well before it was on the radar.”

To confirm the virus’s current presence, the research team conducted field surveys in Southern California in 2023. Lab testing verified the virus in fresh cotton samples, marking California’s first confirmed case of CLRDV.

The research team utilized public genetic repositories to reanalyze older samples. This data-mining approach uncovered viral genetic sequences closely related to current strains, providing a more comprehensive understanding of CLRDV’s geographic and temporal spread. The study highlights the critical role of open-access genetic databases in enhancing plant disease surveillance and preparedness.

In a surprising twist, traces of the virus were also found in a cow gut sample from a separate California study. Researchers suggest the cow likely consumed CLRDV-contaminated plant material, emphasizing the virus’s broader environmental presence without indicating animal infection.

The study also revives discussions about “bronze wilt,” a mysterious condition affecting cotton for years. Researchers propose that CLRDV may be linked to these symptoms, a hypothesis gaining traction as new data aligns with this possibility.

Dr. Michelle Heck of the USDA Agricultural Research Service emphasized the significance of the findings. “For growers, this is both a warning and an opportunity,” she said. “The virus has been more widespread and persistent than previously believed. Understanding why it went undetected and why it’s becoming more problematic now is essential for creating effective control strategies.”

The study underscores how modern tools—ranging from bioinformatics to interdisciplinary collaboration—are redefining agricultural research and equipping scientists to detect threats hidden in plain sight.

Source:https://phys.org/news/2025-05-cotton-virus-circulated-undetected-years.html

This is non-financial/medical advice and made using AI so could be wrong.