Blog Archives

JenREES 5/13/24

Wheat Fungicide Considerations: Part of the area receiving this news column grows wheat for grain as it’s a great crop in rotation. The wheat has looked tremendous this year! Varieties that are susceptible to stripe rust are showing low to medium disease pressure. Wheat ranges from the flag leaf through late boot/early heading stages. Last week, the question was if growers should spray a fungicide to protect the flag leaf from stripe rust. I’m unsure how many still have that question this week but am writing about the tradeoffs I talked about with growers.

We did have a few growers choose to apply fungicide to protect the flag leaf as their wheat had good yield potential and the variety was very susceptible. That was most likely the best decision for these specific field situations with how quickly stripe rust was setting in in their wheat with the cooler conditions and the high humidity within the canopy. It’s important to know one’s economics to make that individual situation as there’s potential we may need a fungicide application for wheat scab (fusarium head blight) prevention as well. A map of where stripe rust has been observed can be found at: https://go.unl.edu/98zy Please note the map doesn’t reflect the fact that it’s also observed in Nuckolls and Webster counties.

Wheat beginning to flower. Notice the yellow anthers in the center of the head. Anthers will then appear at the top and bottom of the head.

With non-irrigated wheat and the economics of it, many try seeing if we could get by with one fungicide application at flowering. A fungicide app at flowering to prevent wheat scab will also kill any fungi present on the leaf surfaces. Fungicide options include:  Prosaro, Prosaro Pro, Caramba, Proline, Miravis Ace, and Sphaerex. Applying when 30% of the wheat is at beginning flowering (seeing yellow anthers in the center of the head) provides the best timing and efficacy. Applying too early before flowering or after the majority of the wheat is past 50% flowering doesn’t provide as good of efficacy. I realize the timing is tough. We normally have a 3-5 day window to get fungicides applied timely and efficacy isn’t guaranteed to be greater than 70%. Efficacy also improves when we can increase the gallonage of aerial apps to 4-5 gallons/acre. You can monitor the potential for wheat scab risk at: https://www.wheatscab.psu.edu/.

Roller Crimping Workshop May 22: For growers and ag industry professionals interested in learning more about roller crimping, Nebraska Extension is hosting a roller crimper workshop from 9:30-11.30 am. Wednesday, May 22 at the University of Nebraska Eastern Nebraska Research, Extension and Education Center, 1071 County Rd G, Ithaca. We’re also seeking growers to speak about their experiences with roller crimping at this workshop, so please let us know if you’re interested in that.

Roller crimpers are used to mechanically terminate cover crops without soil disturbance and ideally create a thick mulch that will act as a weed barrier. Crimpers are used by organic farmers, regenerative farmers and others who, for various reasons, want to reduce herbicide inputs and/or improve weed management with their cover crops.

During this short program, we will show a roller crimper in action, invite farmers to share their experiences with crimping, and discuss what conditions must be met to be successful with this termination method. Demonstration plots with small grains of barley, oats, rye, triticale, and wheat will be showcased to compare the differences amongst them side by side. On-site registration begins at 9 a.m. For more information, please contact Katja Koehler-Cole at kkoehlercole2@unl.edu. This event is sponsored by Nebraska Extension and the USDA Transition to Organic Partnership Program.

Intro Crop Scouting: Also, for those interested in learning about introductory crop scouting, we’ll be having a clinic on May 21st at ENREEC near Mead. More info: https://go.unl.edu/29qk.

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.