Stagonospora nodorum Blotch (formerly Septoria nodorum)

Joe Moade
CPS Tangent

We recently received an email alert from OSU cereals specialist Mike flowers regarding Stagonospora nodorum Blotch (formerly Septoria nodorum).   




All,
I wanted to alert everyone to an emerging disease problem in western Oregon.  Stagonospora nodorum Blotch (formerly Septoria nodorum) seems to be rearing its ugly head this year.  This leaf disease is very similar to the Septoria tritici that we usually see in western Oregon (see attached pictures).  The main difference is that there are no black spots (pycnidia) in the lesions.  The pycnidia of Stagonospora nodorum are brown and very difficult to see.  In addition, if left uncontrolled Stagonospora nodorum can have a significant effect on yield if it infects the wheat head.  Therefore, it is very important that growers control this disease with fungicides to prevent further infections.

Walking my variety trials today with Chris Mundt and Bob Zemetra we found that many of the commonly grown varieties are infected with Stagonospora nodorum.  Thus, this is likely not a variety specific issue (however field of Skiles have been hit pretty hard).  Growers and crop consultants are encouraged to scout all their fields and treat them when necessary.  It is important to scout fields closely as from a distance the fields can look like they are infected with stripe rust, when in fact it is Stagonospora nodorum.  I have also attached a publication that shows the efficacy of the common fungicides on Stagonospora nodorum. 
If you have any questions, please feel free to give me a call at 541-737-9940.

Mike

Michael Flowers, Ph.D.
Extension Cereal Specialist
Oregon State University
119 Crop Science Building
Corvallis, OR  97331
Phone: 541-737-9940
The Good news to this potential problem is that we have effective fungicides that are very good at preventing/controlling the damage.  Please take time to review with your fieldman your wheat disease control program to make sure you are covered.