Common rust (Puccinia sorghi) of corn is developing early and is widespread this year, according to industry and extension personnel. The weather the past few weeks has been very conducive for the development of this disease. The pathogen does not overwinter in Iowa; the spores are blown north from rust-infected corn plants in the southern United States every year.
|Common maize rust.|
Seed corn producers should scout for the rust pustules and make decisions about whether to spray a fungicide. Our guidelines and a list of fungicides were presented in the June 26, 2000, issue of the Integrated Crop Management newsletter, pages 114-115 . Relative susceptibility of the inbred to rust and the outlook for continued weather favorable for rust development should be considered in any decision-making process. Common rust develops best with cool nights and adequate moisture (dew or rainfall).
This article originally appeared on page 131 of the IC-484(17) -- July 10, 2000 issue.