Options for Stripe Rust in Wheat


Stripe rust has exploded in wheat in the past 3-7 days in South-Central Nebraska due to theIMAG5065-1 rain and cooler weather.  Nebraska Extension is receiving numerous questions regarding options to consider.  Rain has also increased our risk for Fusarium Head Blight (head scab).

Wheat is at such a variety of stages in the area; many fields are just heading and/or flowering right now while others are in soft-dough.

Stripe rust on the flag leaf, as shown in this photo, will continue to progress with cool, wet conditions, reducing yield.  If your fields are currently yellow with stripe rust, here are a few options:

1-Do nothing and see what happens regarding what yield is obtained.  If your wheat is past flowering, fungicide application is not an option as all fungicides would be off-label.

IMAG5057-1

Susceptible wheat varieties to stripe rust that have not been treated with a fungicide to date have a yellow cast to them in South-Central Nebraska.

2-If your wheat is headed and beginning to flower, you could still consider a fungicide application of Caramba or Prosaro.  Both are labeled for headed and flowering wheat.  There’s a 30 day pre-harvest restriction for both.  Rainfast varies from ¼ hour to 2 hours or when dry depending on environmental conditions.  Both fungicides can help prevent scab and control rust on the plant. However, research has shown that best scab prevention occurs when wheat is headed and 30% of the plants are in the beginning flower stage.  Application within 5 days of these criteria still showed positive results.  Research showed that application before or after this time period greatly reduced effectiveness of preventing scab.  Understandably, the economics of a fungicide application are tight with current wheat prices.  The following article includes economic considerations.

3-Consider haying it.  Dr. Bruce Anderson, Nebraska Extension Forage Specialist shared the following:

“Baling hay or chopping silage are two potential options.  Rust pustules are not toxic to cattle although sometimes the spores can irritate respiration.  It can be difficult to make good silage, though.  Rusty leaves dry out rapidly so it can be hard to get the best moisture content for silage packing and fermentation.

Usually it is best to harvest rusty wheat hay just before heading to retain reasonable forage quality.  As plants mature further, quality can decline rapidly.  Digestibility of rust affected cells is much lower than that of normal cells.  Fortunately, protein doesn’t seem to be affected greatly.  Properly made hay should not deteriorate in the bale due to the rust any more than normal.

Be sure to have the forage tested before feeding.  It is likely that nutrient concentration will differ from typical wheat hay so testing will help in developing rations.  Also consider the impact of removing the wheat residue.  Adequate residue helps retain soil moisture, boosting yield of your next crop.

There never are good choices when problems like this develop.  All you can do is weigh your options and choose what is best for you.”

Also, please continue to check out UNL CropWatch for wheat disease and all our crop updates.

About jenreesources

I'm the Crops and Water Extension Educator for York and Seward counties in Nebraska with a focus in irrigated crop production and plant pathology.

Posted on May 28, 2015, in Crop Updates, Diseases and tagged , , , , , , , , , . Bookmark the permalink. Leave a comment.

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