Date of this Version
Published by The American Phytopathological Society January 2011, Volume 95, Number 1, Page 73 http://dx.doi.org/10.1094/PDIS-07-10-0541
In September 2009, the University of Nebraska–Lincoln Plant and Pest Diagnostic Clinic received leaf samples of hybrid corn (Zea mays L.) displaying long, necrotic lesions with wavy margins. The lesions had discontinuous water-soaked spots that are indicative of Goss's bacterial wilt and leaf blight. The symptomatic leaves were submitted from Dallam County, located in the Texas Panhandle (northwest Texas). According to the USDA Farm Service Agency and the National Agricultural Statistics Service, in 2009 Dallam County had 54,025 ha planted to corn. This is approximately 19% of the total corn planted in the 26 counties in the Texas Panhandle and 6% of the total corn planted in the state of Texas. Extracts from the infected leaf tissue tested positive for Clavibacter michiganensis subsp. nebraskensis with a commercially available ELISA test (Neogen Inc., Scotland, UK). Isolation from the infected tissue onto CNS selective media (1) resulted in round, dark orange, mucoid colonies that tested gram positive with the Gram-stain test. BLAST nucleotide sequence alignments of the amplified 500-bp 16S rRNA region of the suspect culture's genome (2) revealed a 96% similarity for C. michiganensis subsp. nebraskensis (NCBI BLAST Accession No. U09381.1).