Oat Crown Rust on Forages

Reports have started concerning crown rust of oats in fields that were planted as cover crops or to be used as a forage later in the season.  This disease rarely reaches Ohio due to earlier planting and maturity.  However, this continues to be an unusual year. Scout for this in your fields. If it is present, then the next question is should this be controlled?

For oats planted solely as a cover crop, no management is necessary. This rust will not overwinter on oats in Ohio, unless the winter is extremely mild. The alternate host, many rust fungi complete their life cycle on two different plant species, is common buckthorn. How well it will overwinter on these plants in Ohio is also unknown.

Questions have been asked about whether feeding rust-affected oats would result in problems with mycotoxins such as vomitoxin. The answer is no, the crown rust fungus does not produce toxins that are harmful to humans or animals, so feeding rust-affected plants would not be a concern from the standpoint of mycotoxin contamination.   

For oats planted alone, not in a mixture, for forage. Management is recommended to preserve feed quality, as severe rust may affect palatability, and consequently, feed intake. If your area has poor quality feed, then this is something to consider. 

  1. Early cutting of the forage, especially if the rust has just started.
  2. Apply a fungicide – aiming to protect as many leaves as possible.  This is the part that is a challenge, as most recommendations and labels are targeting to protect the flag leaf and head.  The recommendations on the label are then for suppression of foliage diseases is the best approach. On the following labels, it allows for plants treated with the fungicide to be used as hay or forage.  There may be some others, but this is what we have found.

Crop

Product

Rate

Pre-harvest interval

Oats alone

some Oat mixtures**

Priaxor Xemium Brand Fungicide (BASF)

4 fl oz/A

14 days post application

Oats alone

Tilt (Syngenta)

4 fl oz/A

7 days for forage & hay

Quilt Xcel (Syngenta)

10.5-14 fl oz/A

7 days for forage & hay

Trivapro Fungicide

(Syngenta)

13.7 fl oz/A

7 days for forage & hay

Stratego (Bayer)

7 fl oz/A ONLY

30 days for forage

45 days for hay

 

Headline (BASF)

6 fl oz/A

14 days for hay or green chopped oats

** Be sure that all crops in the field are on the label.

About the C.O.R.N. Newsletter

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.