Agronomy Talk

Agronomy Talk: Springtime Management of Winter Wheat

Published on Thursday, February 07, 2019

Winter wheat breaks dormancy if there is a two-week period with an average temperature of at least 41°F. As soon as the plants resume growth, you need to get back out in the field so that you can make critical decisions about nitrogen, insecticide, fungicide and most importantly, preserve yield potential.

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Nitrogen Management

Splitting the nitrogen application reduces risk of loss to the environment, and reduces risk that the plants take up too much nitrogen at once and become rank. Rank plants are more likely to lodge.

PFR PROVENTM - two pass N system to maximize yield & minimize N losses of UAN or Urea

Use tiller counts to determine necessity for early N application and rate

    • Target: 70-100 Tillers/ft2
    • Less than 70 tiller/ft2
      • apply 50-60% of N at Feekes 3 (green-up)
      • balance at Feekes 5 (stem elongation)
    • Greater than 70 tiller/ft2 = Target Feekes 4-5
    • See chart belw for rates:

# of Tillers

Nitrogen to Apply

Feekes 3

Feekes 5

0 - 2

40 – 50 lbs. (50-60 lbs. no-till)

40 – 50 lbs. (50 – 60 lbs. no-till)

3 - 4

30 -40 lbs. (40 – 50 lbs. no-till)

50 – 60 lbs. (60 – 70 lbs. no-till)

5 or more

None

80 – 90 lbs. (110 – 120 lbs. no-till)

 

Tiller counts are essential for making management decisions. Photo from Michigan State.

https://www.morningagclips.com/evaluating-seedling-wheat-stands-this-fall/

  • N Rates
    • 1.2 lbs. N. / Bushel
      • 100bu = 120 lbs. N.
      • 80bu = 96 lbs. N.
      • 65bu = 78 lbs. N.
    • PFR data
      • 6 Year Multi Location = 96-109 units per acre of Nitrogen
  • Single Pass
    • Less than 70 tillers/ft2: apply in Feekes 3 (green-up). Increased spring N lss potential!
    • Mre than 70 tillers/ft2: wait until Feekes 5 (stem elngation)
    • Use a nitrificatin inhibitor such as Agrotain Plus®, Instinct®, or Nutrisphere®
  • Goal is 60+ harvestable heads/ft2

Palisade® EC

Pallisade EC is a Plant Growth Regulator (PGR) that keeps the plant for getting too tall, which reduces the risk of lodging.

  • PFR Proven applied at Feekes 5– 6.3 Bu./A = $15.31/A (12oz rate)

Fungicides

Warm, wet weather during flowering increases the odds of head scab infection. Fusarium head blight, also called FHB or head scab, is a fungal disease caused by Fusarium graminearum. This fungus produces a vomitoxin (DON) in the grain. Grain with high DON levels in unsuitable for feed and is likely to be rejected at the elevator. Apply fungicide during early flowering at Feekes 10.5.1 or when more than 50% of plants are flowering to mitigate head scab. In most areas, flowering is a 7-10 day window. In general terms, it is better off to spray a few days too late than to spray too early before anthers are visible. Local scab predictions are available through local extension service.

A single application at Feekes 10.5.1 (flowering) provides best protection against foliar disease and fusarium head scab.

  • PFR Proven Data
    • Single Applicatin at Flowering (Feekes 10.5.1)
      • +5.6 bu./A = $15.40/A. (6.5 oz. Prosaro® @ Flowering, 5yr data)
      • +6.7 bu./A = $20.73/A (13.5 oz. Caramba® @ Flowering, 7yr. data)

Avoid strobulirin fungicides after flowering because their use can increase DON in grain if applied after Feekes 8.

If you are interested in other PFR Proven products and practices to help you make the most of your wheat crop, check out the PFR Wheat Book available at www.beckshybrids.com under the PFR tab.

https://www.ag.ndsu.edu/cpr/plant-science/timing-of-fungicides-for-scab-control-in-wheat-and-barley-06-27-13

Flowering on each wheat head starts at the middle of the head, then moves up and down. Similarly, tillers will flower after the main head. Time your fungicide application to optimize the number of open flowers, while not waiting so long that you allow the disease to take hold.

Insects

It is important to use an insecticide seed treatment like Escalate yield enhancement system and/or a fall applied insecticide to control aphids. Aphids are piercing sucking insects. Direct feeding via piercing-sucking mouthparts removes plant sap and damages plant health. Some aphid species (bird cherry-oat aphid in particular) also vector a viral disease called Barley Yellow Dwarf. There is no control option for the virus, so keep aphid populations low to avoid yield loss.

  • Aphids = Barley Yellow Dwarf Virus
    • Temps > 48⁰F = aphid activity
    • > 10 aphids/ft rw in the winter/spring = Spray!

Armyworm feeding on the leaves typically occurs at night. In the daytime, the larvae hide in litter at the soil surface or under clods of soil.

  • True Armyworm
    • ≥ 4 armywrms / ft2 = Spray!

https://entomology.k-state.edu/extension/insect-information/crop-pests/wheat/armyworm.html

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Author: Steve Gauck

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