Wheat

Wheat Foliar Diseases and Head Scab Risk

Wet conditions have stalled corn and soybean planting but may be ramping up the risk of foliar disease in wheat.

Ohio’s wheat crop is either at or past Feeke’s Growth Stage 10 (boot) and now is the time to scout fields if you have not already. Foliar diseases like Septoria leaf spot and powdery mildew thrive in cool, wet conditions and can potentially reduce grain yield and quality by damaging the flag leaf.  When scouting for Septoria leaf spot, look for irregular brown blotches that may become bleached in appearance and contain small, blackish dots (fungal fruiting bodies). The main sign of powdery mildew is fluffy, whiteish-gray powdery growth (called pustules) on the leaf surface and lower stem. As the pustules age they will become covered with black dots on the surface.

As temperatures increase this week, keep an eye out for other potential foliar diseases such as Stagonospora leaf blotch and leaf rust. Stagonospora leaf blotch symptoms develop when temperatures are between 68- and 81-degrees Fahrenheit and typically appear as brown, lens-shaped lesions surrounded by yellow halos. Leaf rust also prefers warmer temperatures coupled with rainy, humid conditions and can be diagnosed by its round, orangish-red pustules scattered across the leaf surface.

If disease is present and conditions remain favorable for further disease development, consider a fungicide application between Feekes Stages 8 through 10 to prevent disease from reaching the flag leaf. Fungicide options can be found at https://cropprotectionnetwork.org/publications/fungicide-efficacy-for-control-of-wheat-diseases.

Once wheat reaches flowering, Fusarium head blight or head scab becomes the main concern. Risk for head scab infection and deoxynivalenol (DON) contamination is greatest when wet, humid conditions coincide with flowering. To estimate the risk of infection in your area, utilize the Fusarium Risk Assessment Tool just prior to flowering. It is available at http://www.wheatscab.psu.edu/ If a susceptible variety is planted and the risk of FHB is moderate to high, consider a fungicide application of Prosaro, Caramba, Proline, or Miravis Ace at Feekes Growth Stage 10.5.1 (early flowering, Figure 3) or within the first 4 day after Feekes 10.5.1.

2025 Wheat Fungicide options

Our current weather patterns may increase the disease potential for our wheat crop this year.  Since its too wet to plant, now would be a great time to scout your wheat fields.  If disease is present or if conditions remain favorable for further disease development, you may need to consider a fungicide application.   The table below contains the 2025 Wheat Fungicide Efficacy ratings .

Click here to download a PDF copy of this table

Wheat Management for Spring 2025

Today managing your wheat crop requires knowledge of the different growth stages of the plant.  Growth stage identification is critical for scouting and proper timing of fertilizer and pesticide applications.  Each week throughout the rest of the growing season I will discuss the various wheat growth stages I am seeing in our wheat fields and management issues at each stage.  This week I will focus on Feekes 9 and 10. Most of our wheat has progressed to the Feekes 9 growth stage,  some fields are or soon will be in Feekes 10 growth stage.

Feekes 9 – Ligule of flag leaf visible.

The flag leaf is completely emerged from the whorl. Flag leaf and the next-to-last leaf (penultimate leaf ) combined account for 70 to 90 percent of the photosynthates used for grain fill and must be protected for the plant to develop to its full potential.

 

Management.

Scout for insects and diseases. Consider a fungicide application to protect the flag leaf if foliar diseases are present on the lower canopy. Nitrogen application can increase grain protein levels.

Feekes 10 – Boot.

The head is inside the leaf sheath giving it a swollen appearance.  The flag leaf sheath and peduncle elongate and the developing head is pushed through the flag leaf sheath.  Temperatures below 28 degrees Fahrenheit may cause damage to the developing head.

 

Management.

Scout for insects, weeds, and diseases. Application of 2,4-D after wheat reaches the boot stage of growth can result in trapped heads, missing florets, or twisted awns.

Wheat Management for Spring 2025

Today managing your wheat crop requires knowledge of the different growth stages of the plant.  Growth stage identification is critical for scouting and proper timing of fertilizer and pesticide applications.  Each week throughout the rest of the growing season I will discuss the various wheat growth stages I am seeing in our wheat fields and management issues at each stage.  This week I will focus on Feekes 7. Most of our wheat has progressed to the Feekes7 growth stage, some fields are approaching Feekes 8 growth stage and beyond.

Feekes 7 Growth Stage – Second Node Visible.

At the Feekes 7 growth stage, the second node is visible above the soil surface. These nodes are usually seen as clearly swollen areas of a distinctly different (darker) shade of green than the rest of the stem. Wheat will still respond to nitrogen fertilizer applied at Feekes 7 if weather prevented an earlier application; however, mechanical damage may occur from applicator equipment. A video demonstrating for identifying Feekes 7 and 8 growth stages can be found here: https://www.youtube.com/watch?v=bnV57AhUt-Y&list=PLYlh_BdeqniJ8oD8TnyGhQHRd96ptV0Yt&index=2

Management

Plant growth regulators may be applied at this growth stage.  Scout for insects, weeds, and diseases.

Wheat Management for Spring 2025

Today managing your wheat crop requires knowledge of the different growth stages of the plant.  Growth stage identification is critical for scouting and proper timing of fertilizer and pesticide applications.  Each week throughout the rest of the growing season I will discuss the various wheat growth stages I am seeing in our wheat fields and management issues at each stage.  This week I will focus on Feekes 6.  Most of our wheat has progressed to the Feekes 6 growth stage, some fields are approaching Feekes 7 growth stage.

Feekes 6 – First Node Visible. 

Prior to Feekes 6.0, the nodes are all formed but sandwiched together so that they are not readily distinguishable. At 6.0, the first node is swollen and appears above the soil surface. This stage is commonly referred to as “jointing.” Above this node is the head or spike, which is being pushed upwards eventually from the boot. The spike at this stage is fully differentiated, containing future spikelets and florets.

Split wheat stem showing developing spike.

You can remove and carefully examine plants for the first node. It can usually be seen and felt by removing the lower leaves and leaf sheaths from large wheat tillers.  A sharp knife or razor blade is useful to split stems to determine the location of the developing head. The stem is hollow in most wheat varieties behind this node.

 

 

Management.

By Feekes 6.0, essentially all weed-control applications have been made. Do not apply phenoxy herbicides such as 2,4-D, Banvel or MCPA after Feekes 6.0, as these materials can be translocated into the developing head, causing sterility or distortion. Sufonyl-urea herbicides are safe at this growth stage, but for practical reasons, weed control should have been completed by now. Small grains can still show good response to N topdressing at this time.

Wheat Management for Spring 2025

Today managing your wheat crop requires knowledge of the different growth stages of the plant.  Growth stage identification is critical for scouting and proper timing of fertilizer and pesticide applications.  Each week throughout the rest of the growing season I will discuss the various wheat growth stages I am seeing in our wheat fields and management issues at each stage.  This week I will focus on Feekes 5.  Most of our wheat has progressed to the Feekes 5 growth stage, some fields are in Feekes 6 growth stage.

Feekes 5 – Leaf sheaths strongly erect. 

 

The beginning of the stem elongation phase.  The pseudo-stem is strongly erect and leaf sheaths are elongated. The developing head reaches the terminal spikelet stage and is pushed up into the pseudo-stem.

Terminal spikelet occurs at Feekes 5. This stage marks the completion of the spikelet initiation phase. At this stage, the number of spikelets per head has been determined.   Stress during this stage can reduce total number of kernels per head.

The first hollow stem stage occurs when there is approximately 0.6 inch of hollow stem below the developing head.  Crop water use is about 0.1 inch per day.

Management.

This is an ideal stage for spring topdress nitrogen application. Weed control efforts should be made prior to or during Feekes 5.0 with 2,4-D and other labeled herbicides. This is also a good stage to begin scouting for foliar diseases.  Tillers developing after this time are not expected to contribute to yield.

Spring Nitrogen Recommendations for Winter Wheat

Winter wheat is beginning to show signs of green-up (Figure 1). Nitrogen fertilizer should be applied to winter wheat between green-up and Feekes growth stage 6. (If you need a reminder on how to assess if wheat is at Feekes GS 6, see this video: https://www.youtube.com/watch?v=D_f3VrqzV5c)

Nitrogen applied too early has the potential to be lost since wheat will use little N until after jointing. Urea-ammonium nitrate (UAN) or 28% has the greatest potential for loss and ammonium sulfate the least. Urea will have little potential for loss as long as it does not volatize. No stabilizer will protect the nitrate component of UAN, which is roughly 25% of the total N in UAN at application time.

Wheat fertility guidelines follow the Tri-State Fertilizer Recommendations for Corn, Soybean, Wheat, and Alfalfa (available here: https://extensionpubs.osu.edu/search.php?search_query=Tri-state&section=product). Spring N rates depend on wheat yield potential (Table 1). If you prefer to be more specific, the following equation may be used for mineral soils, which have both 1 to 5% organic matter and adequate drainage:

N Rate = (1.33 x Yield potential) – 13

As a producer, you can increase or reduce your N rate by changing the value for yield potential. Thus, a realistic yield potential is needed to determine the optimum N rate. To select a realistic yield potential, look at wheat yield from the past five years. Throw out the highest and lowest wheat yield and average the remaining three wheat yields. This three-year average should reflect the realistic yield potential.

No credit is given for previous soybean or cover crops, since it is not known if that organic N source will be released soon enough for the wheat crop. The Tri-State Fertilizer bulletin recommends that you subtract from the total (spring N) any fall applied N. We recommend taking no more than a 20 lb/A credit even if you applied a larger amount. Whether you deduct fall N depends how much risk you are willing to take and your anticipated return of investment from additional N. Based on the equation above and deducting 20 lb from a fall application, a spring application of 100 lb N per acre would be recommended for a yield potential of 100 bu, 90 for 90 bu potential; and 70 for a 80 bu potential.  Nitrogen rate studies at the Northwest Agricultural Research Station over the past 20 years have shown the optimum rate varies depending on the year. However, averaged over years, yield data from these studies correspond well with the recommendation equation given above. These studies have also shown apart from one year, yields did not increase above a spring rate of 120 lb N per acre.

Wheat generally does not benefit from a nitrification inhibitor since temperatures are relatively cool at application time and the application is made to a growing crop, this is especially true as the crop approaches Feekes GS 6. However, urea may benefit from a urease inhibitor (products containing NBPT) if conditions for volatilization exist for several days after application. These conditions would include an extended dry period with warm drying temperatures (risk increases with temperatures above 70°F) and evaporating winds. Urea applications need at least a half inch rain within 48 hours to minimize volatilization losses unless temperatures remain relatively cool. The urease inhibitor will prevent volatilization for 10 to 14 days with the anticipation of a significant rainfall event during this time.

ESN or polymer coated urea will reduce the potential for N loss from leaching, denitrification, and volatilization. Since these conditions are unlikely to occur in most years, it may not be economical to use this product. Cool weather may prevent the timely release of N from ESN, so if ESN is applied, it should be mixed with urea or ammonium sulfate and be no more than 60% ESN.

A split application of N may be used to spread the risk of N loss and to improve N use efficiency. However, Ohio State University research has not shown a consistent yield increase from this practice compared to a single application after green-up and multiple applications are more costly compared to a single application. In a split system, the first application should be applied no sooner than green-up. A smaller rate should be applied with the first application since little is needed by the crop at that time and the larger rate applied closer to Feekes GS 6.

Ohio Crop Weather

Source: USDA

Sustained Wet Conditions

Heavy rains last week saturated fields and prevented any large-scale planting activities, according to Ben Torrance, State Statistician, USDA NASS, Ohio Field Office. Topsoil moisture conditions were rated 31 percent adequate and 69 percent surplus. Statewide, the average temperature for the week ending on April 14 was 56.8 degrees, 9.4 degrees above normal. Weather stations recorded an average of 1.86 inches of precipitation, 0.98 inches above average. There were 0.7 days suitable for fieldwork during the week ending April 14.
Farmers reported that with the excess rain, the only field work that could be done was applying herbicide and fertilizing wheat. Oats were 11 percent planted. Winter wheat was 51 percent jointed and winter wheat condition was 70 percent good to excellent. Warmer than normal conditions continued to push fruit crop development.

Ohio Crop Weather – April 1, 2024

Cloudy and Cool at Season’s Start

Cloudy and cool conditions prevailed across the State as farmers began early-season field activities, according to Ben Torrance, State Statistician, USDA NASS, Ohio Field Office. Topsoil moisture conditions were rated 1 percent very short, 6 percent short, 69 percent adequate, and 24 percent surplus. Statewide, the average temperature for the week ending on March 31 was 46.6 degrees, 1.6 degrees above normal. Weather stations recorded an average of 0.81 inches of precipitation, 0.05 inches above average. There were 2.1 days suitable for fieldwork during the week ending March 31. Farmers began the season with fertilizer and manure applications and tillage. Recent precipitation left some fields saturated, with ponding reported. Oats were 1 percent planted. Winter wheat was 4 percent jointed and winter wheat condition was 67 percent good to excellent. In southern counties, stone fruit and pear trees were in bloom and fruiting plants began to emerge from dormancy. Hay fields were greening, supported by moderate temperatures and adequate precipitation. This is the first weekly crop and weather report of the 2024 season. A series of weekly crop progress and condition reports will be published each Monday at 4:00 p.m. ET throughout the crop season. The reports will cover planting and harvesting activities, crop development, weather data, and timely crop management information provided by farmers, USDA, and Ohio State University experts. For the earliest possible access, look for these reports on the internet shortly after the 4:00 PM release time.