Tar spot caused by Phyllachora maydis found in more US states
Tar spot caused by Phyllachora maydis (EPPO Alert List) is an emerging disease of maize (Zea mays) in the USA. It was fist found in 2015 in Illinois and Indiana, and then in other states (Florida, Iowa, Michigan, Minnesota, Missouri, Ohio, Wisconsin). More recently, P. maydis has also been reported from Georgia, Kentucky, Nebraska, New York, and Pennsylvania.
Georgia
The US Early Detection & Distribution Mapping System indicates that P. maydis has been found in Georgia since August 2021 in several locations (counties of Ben Hill, Brooks, Bulloch, Calhoun Clay, Colquitt, Dooly, Evans, Grady, Irwin, Marion, Seminole, Tift, Turner, Wayne, Wilcox).
Kentucky
The first case of tar spot caused by P. maydis in Kentucky was confirmed in September 2021. The diseased sample had been collected from a maize plant which was part of a local breeding trial (University of Kentucky, 2021).
Nebraska
In October 2021, P. maydis was reported from Nebraska. The disease was confirmed in several eastern Nebraska counties (Dakota, Thurston and Burt). Disease incidence and severity were both reported to be low (University of Nebraska, 2021).
New York
The US Early Detection & Distribution Mapping System indicates that P. maydis was found in October 2021 in Erie.
Pennsylvania
In late September 2020, foliar symptoms resembling those of tar spot caused by P. maydis were observed in Lancaster county, in a maize (Zea mays) field growing several non-commercial hybrids. Disease incidence and severity varied according to the different hybrids from 0 to 100% and from 1 to 40%, respectively. The identity of the fungus was confirmed by morphological and molecular methods. For the moment, the economic impact of tar spot in Pennsylvania remains to be assessed (Collins et al., 2021).
Sources
Collins AA, Bandara AY, May SR, Weerasooriya DK, Esker PD (2021) First report of tar spot of maize (Zea mays) caused by Phyllachora maydis in Pennsylvania. Plant Disease (early view). https://doi.org/10.1094/PDIS-11-20-2456-PDN
INTERNET
- EDDMapS (online) Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/ (last accessed 2021-11-08).
- University of Kentucky. College of Agriculture, Food and Environment (2021-09-20) Tar spot found in Kentucky corn by K Pratt. https://news.ca.uky.edu/article/tar-spot-found-kentucky-corn
- University of Nebraska-Lincoln (2021-10-21) Tar spot disease of corn confirmed in several Nebraska counties by T Jackson-Ziems and K Broderick. https://cropwatch.unl.edu/2021/tar-spot-disease-corn-confirmed-several-nebraska-counties