Southern Corn Rust Spreading in Southwest Georgia

by | Jun 20, 2014 | Corn, Disease, Field Crops, Pest Management

Source:  Seminole Crop E News
Rome Etrhedge, UGA Seminole County Coordinator

Southern rust has shown up in a number of corn fields in Seminole County, Georgia. Rome Ethredge is urging corn farmers to apply fungicides again, if it’s been 3 weeks since their tassel application.

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Decatur County agent Justin Ballew with southern corn rust on the lower leaves of some corn that had been sprayed much earlier with fungicide.

Here’s an update by UGA Extension plant pathologist Bob Kemerait.

1.  Southern corn rust was confirmed in yet another county (Pierce, James Jacobs) this week . Rust is early this year.  More importantly, it is widespread this year and found in fields that have not yet reached the tassel stage. (See the map below or go to http://scr.ipmpipe.org/ for the most current map).

2.  Sporadic afternoon and evening thunderstorms are likely to further move rust spores and also provide the moisture important for infection.

3.  I believe that this is the most significant threat of southern rust in Georgia in the past 10 years.

4.  Southern corn rust (SCR) reduces the photosynthetic capacity of infected leaves. More importantly, a field where SCR is not controlled may develop extensive lodging problems as the stalk is cannibalized for nutrients to feed the ear.

5.  Dr. Dewey Lee and I agree that protecting a crop from rust though the dough stage is beneficial.

6.  I recommend that growers spray by tassel growth stage and then again 2-3 weeks later, depending on the product used in the first application.

7.  On corn where rust is a severe problem, we have seen fungicides protect 25+ bu/A.

So Corn Rust Map

 

Doug Mayo
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