Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Peanut Seedling Disease

Posted by romeethredge on May 30, 2013

I am seeing some aspergillus  niger  seedling disease in peanuts. It’s usually not a big enough problem to worry too much about. It’s worse when it’s hot and dry. You can see the black sooty growth on the peanut stem when you dig it up._DSC6503

Here’s info from Dr. Bob Kemerait, UGA Extension Plant Pathologist,

“The weather has turned hot and dry over the past couple of weeks and for the young peanut crop, this usually means “Aspergillus crown rot”.  Why?  The hot soils scald the tender peanut shoot and makes it easily infected by the fungal pathogen Aspergillus niger.  Symptoms include the rapid death of RANDOM young plants in the field and the presence profuse, black, sooty fungal sporulation on the infected tissue  This problem is less severe when growers use a good fungicide seed treatment, more severe when growers save their seed or where lesser-corn-stalk borers are also a problem.  Irrigating a field and rainfall helps to reduce the severity of this problem.”

 _DSC6500

Here’s an excerpt from the 2013 UGA Peanut Update

Managing Seedling Diseases:

Seedling diseases were typically not a concern for peanut growers in Georgia prior to the arrival of the tomato spotted wilt virus. Even if  some plants were lost in a stand, the neighboring peanut plants were often able to compensate for the loss by growing into the vacated space. However, it is clear that spotted wilt can be devastating when fields have poor stands. For this reason, getting a good stand has become critical for growers. Below are some management techniques to reduce seedling diseases (primarily caused by Rhizoctonia solani and Aspergillus niger).

 

1. Rotate peanuts with grass crops to reduce the populations of Rhizoctonia solani.

2. Plant the peanut crop when soil temperatures are warm enough to produce rapid, vigorous germination and growth. This can help protect the plants from disease. Excessive moisture at planting will also increase the risk of seedling diseases.

3. Use quality seed that has a good germination rating and will grow vigorously.

4. Choose varieties that are known to germinate and emerge uniformly and with vigor.

5. Use only seed treated with a commercial fungicide seed treatment. The seed treatments that are put on commercial seed prior to purchase are outstanding and provide protection for the seed and seedling. Seed treatments include:

a. Vitavax PC

b. Dynasty PD (azoxystrobin + mefenoxam + fludioxonil)

6. Use an in-furrow fungicide where the risk of seedling disease is great or where the grower wants increased insurance of a good stand.

a. Abound at 6.0 fl oz/A in the furrow at planting can provide increased control of seedling diseases, including Aspergillus crown rot.

b. Terraclor (64 fl oz/A) also provides additional control of seedling diseases when applied in-furrow.

c. Growers who are most likely to yield benefits from these in-furrow fungicides are those that have poor crop rotation and a history of seedling disease in the field.

 

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