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Samples needed to assess bacterial blight

<p>Texas AgriLife would like to collect cotton leaf samples with suspected bacterial blight infections.</p>

Various symptoms are associated with bacterial blight. Initial symptoms consist of small, pinpoint lesions on foliage.

  • As the disease progresses, lesions take on a blocky, angular shape as the bacterium is not capable of crossing veins found within leaves.
  • Following systemic infections, veins may become necrotic.
  • Petiole infections result in severe necrosis, which may progress down the limb or branch resulting in a symptom referred to as Blackarm.
  • Premature defoliation and fruit abortion are often associated with the aforementioned symptoms. Later in the season, the bacterium may infect developing bolls causing a boll rot.
  • The appearance of these symptoms differs from foliar symptoms. Such lesions have a circular appearance, as there are no veins within the boll to limit growth of the bacterium.

These symptoms are characteristic of what has been associated with infections caused by Xanthomonas axonopodis pv. malvacearum, race 18 over the past several decades.

If you have any questions regarding the appearance of the disease or need additional information about the sampling please contact either Dr. Wheeler (806-746-6101; or myself (806-632-0762;

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