Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Bacterial Stalk Rot in Corn

Posted by romeethredge on May 23, 2015

I’ve not seen this Bacterial Stalk Rot before but crop consultant, Jim Griffin, brought me some diseased plants from far eastern Decatur county yesterday. We confirmed it with Dr. Bob Kemerait, UGA plant pathology, by photos and discussion.

We scouted the fields and found it in the areas irrigated from a pond. In areas not irrigated by that pond, we didn’t see it. It is in low amounts maybe half of one percent of plants, more in some areas, but it is startling to see. Fortunately, it is reported not to usually spread within the field. The bacterium causes a type of meltdown and you can sometimes smell it before you see it. It really stinks, especially if you cut into the stems. Univ of Nebraska has a good writeup about it. Here’s an excerpt…

“The initial symptom is discoloration of the leaf sheath and stalk at a node. As the disease progresses, lesions develop on the leaves and sheath. Disease then develops in the stalk and rapidly spreads up the stalk and into the leaves. As the decay progresses, a foul odor can be detected and the top of the plant can be very easily removedfrom the rest of the plant. The stalk rots completely and the top collapses. Bacterial stalk rot can affect the plant at any node from the soil surface up to the ear leaves and tassels. Infections that occur high on the plant may impair normal tasseling and affect subsequent pollination. Although it may spread along the plant to infect additional nodes, the bacteria do not usually spread to neighboring plants unless vectored by an insect. Splitting the stalk reveals internal discoloration and soft slimy rot mostly initiating at the nodes. Because the bacteria usually do not spread from plant to plant, diseased plants are quite often found scattered throughout the field. However, there are reports of plant-to-plant transmission by certain insect vectors.

Bacterial stalk and top rot is favored by high temperatures and high relative humidity. It can be a problem in areas of heavy rainfall or where overhead irrigation is used and the water is pumped from a lake, pond, or slow-moving stream.”

 

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