ProMED
http://www.promedmail.org

Source: FarmProgress [summ. Mod.DHA, edited]
https://www.farmprogress.com/crop-disease/southern-corn-rust-cropping-up-in-central-and-eastern-kansas

Kansas farmers have reported southern rust in maize in 4 counties in the state this [2024] season. Farmers should also scout for common rust on maize. Hot and humid days this summer have prepared the conditions for the fungus to blow in from the south, say Kansas State University plant pathologists. Southern rust does not overwinter in Kansas, but blows in annually from more tropical regions. It has become a more prevalent problem in southern states, the experts say.

[Byline: Jennifer M. Latzke]

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Communicated by:
ProMED

[Southern rust (also called polysora or tropical rust) in maize is caused by _Puccinia polysora_. The fungus occurs in most tropical and subtropical regions and can cause significant losses of over 50 percent. Southern rust is favoured by warm, humid conditions. Leaves may die prematurely reducing photosynthetic ability; therefore, if infection has been completed before grain fill, it is more damaging to yield than an infection late in the crop cycle. _P. polysora_ needs living host tissue for survival, and spores are wind dispersed. No alternate hosts of the fungus are known. Resistant or tolerant ('slow rusting') varieties are being developed.

The related species _P. sorghi_ causes common rust of maize.

Pictures
Southern rust of maize:
https://www.lsuagcenter.com/~/media/system/e/0/1/8/e01882b0016a677fae908b45d09ad540/rust2jpg,
https://crop-protection-network.s3.amazonaws.com/articles/photos/southern-rust-Adam-Sisson-35.jpg,
https://washington.ces.ncsu.edu/wp-content/uploads/2014/07/corn.png and via
http://www.ent.iastate.edu/imagegal/plantpath/corn/southrust/

Links
Information on maize southern rust:
https://cropprotectionnetwork.org/encyclopedia/southern-rust-of-corn,
https://cropwatch.unl.edu/plantdisease/corn/southern-rust,
https://doi.org/10.1007/s00122-006-0466-0 and
https://doi.org/10.1186/s42483-021-00102-0 (review)
_P. polysora_ taxonomy:
https://www.indexfungorum.org/names/NamesRecord.asp?RecordID=179511
- Mod.DHA