Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Posts Tagged ‘rust’

Corn – Southern Rust in the Area 2015

Posted by romeethredge on June 8, 2015

There has been some southern rust found in Mitchell county Georgia by County Agent Andy Shirley. It’s now also been found inTerrell County, by Agent Nick McGhee.

Here’s a photo from last year when we had a bad problem with it in our corn fields.


Here are comments from Dr. Bob Kemerait, UGA Plant Pathologist.  “Corn growers in south Georgia should be very much aware NOW that rust is here. 

Current weather patterns increase the risk. 

I believe that any irrigated field corn with good yield expectations and that is at tassel or beyond is a good candidate for treating with a fungicide.

 Corn approaching tassel is also certainly at risk.”

Here are some comments from Dr. Dewey Lee, UGA Grains Scientist.

“Even though this southern rust infection is earlier than usual, most of our corn crop is a little head of schedule.  While this might not be much comfort, it does mean we might have saved at least one spraying.  Last year, it was extremely difficult to stay a head of southern rust because the infectious time was longer than normal due to favorable conditions for infection.  Some corn in the southern areas of the state is as far along as the R3/R4 stage.  This makes it easier to control rust and reduce the impact since it is much closer to maturity.  Much of the corn crop though, is silking to early ear development (R2/R3) which adds roughly 2 to 3 weeks of time to our potential spraying.

If you have good yield potential (and most irrigated growers do), I would consider spraying a combination of fungicides to provide both a curative and preventative type of action.  There are great choices today from lots of sources.  You may not have a current infection taking place, but spores are active and an application of a combination of fungicides will be great insurance and likely prevent yield loss.  As long as southern rust is active, I would consider staying on a 14 day spray schedule or shorter.  This disease can certainly undermine all your efforts this year and significantly reduce corn yields.”

Link to Dewey’s Blog.

Posted in Corn, Plant Pathology | Tagged: , , | Leave a Comment »

Wheat Rust in Mitchell County

Posted by romeethredge on March 20, 2015

My fellow county agent, Andy Shirley, in Mitchell County (Camilla, Ga) reported leaf rust this week in some wheat there.

Click on this link to read his report, Mitchell County Ag News.

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Posted in Plant Pathology, Wheat | Tagged: , | Leave a Comment »


Posted by romeethredge on March 11, 2013

Today, I’ve seen three different types of rust on plants. I’ve seen Oat rust, Wheat leaf rust and Daylily rust. We’ve had good conditions for it, I suppose. We’ve been seeing some rust on oats but it seems to have almost exploded this week in oats being grown for seed, the growers will likely wait for flag leaf emergence, probably another week or so, to apply a fungicide.

Rust on oats.

Rust on oats.

Oat rust.

Oat rust.

The second rust I saw today was wheat leaf rust. The very observant County Agent Andrew Sawyer in Thomas County found some there on Friday and I found some today here in Seminole county at very low levels. Not at all like the levels of oat rust we are seeing.

Flag leaves are just emerging and the rust is low on the plant so growers will likely wait until all flag leaves are out and heading is about done so they get fungicide protection on the flag leaf and hopefully on the head. This all depends on disease progression.

Here’s some  information concerning Leaf Rust from Dr. Alfredo Martinez, UGA Extension Plant Pathologist.

Wheat Leaf Rust.

Reddish-brown pustules develop on leaves and sheaths. These pustules are filled with spores of the fungus. Rubbing an infected leaf will leave rusty colored areas on your fingers. Rust pustules may be very tiny, barely large enough to see with the naked eye, to 1/8 inch in length. Generally, varieties with higher levels of resistance will have smaller pustules than varieties with lower levels of resistance. Varieties with poor resistance will also have larger yellow halos around the pustules. Leaf rust has the greatest effect on yield of the wheat diseases because it develops rapidly during favorable weather.

Rusts are the most economically important group of wheat diseases. More than $5 billion is lost to cereal rusts (leaf rust, stem rust and stripe rust) worldwide each year. The capacity of rusts to develop into widespread epidemics is well documented. Rusts have complex life cycles that involve alternate hosts and several spores stages. Adding to this complexity are the numerous “physiological races” separable by patterns of pathogenicity and virulence on differential hosts. New races continually surface due to the rusts’ ability to mutate and sexually recombine.

Wheat leaf rust.

Wheat leaf rust.

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When I got back into the office I was left several daylily leaves that had the third example of rust I saw today, Daylily rust. It is a bad case and the homeowner will spray right away.

Daylily Rust.

Daylily Rust.


Posted in Plant Pathology, Wheat | Tagged: , | Leave a Comment »

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