Protecting Yield and Quality from Late Season Diseases

T2 & T3 Fungicide Strategies

In general, the 2018 wheat crop is relatively clean from a disease standpoint. Some earlier planted fields with a nice thick canopy do have some powdery mildew however the pressure remains low. There are some fields with low levels of septoria leaf spot as well. If a T1 fungicide was applied, these early season diseases were well looked after.

Knowing what stage your crop is at is critical for fungicide considerations. In the southern end of the province, wheat is starting to come into head and the T3 application has started on the earliest planted wheat. As you move north into Middlesex and Huron, early planted wheat is well into the boot stage and even some heads are starting to emerge. Around the Palmerston area, a majority of the wheat is around GS 33 (3rd node detectable) to flag leaf stage and even some fields are in the boot stage.

Before spraying a T2 fungicide, I encourage everyone to scout their wheat.  Many fields are very clean and not all require a T2 application. Some areas of the province are quite dry and have not received much rainfall whereas other areas have received ample amounts of rainfall this spring. General rules of thumb, dry years are insect years and wet years are disease years. The situations where a T2 fungicide would be beneficial are if 1). You have disease pressure and or conditions that favour disease development are present, control may be necessary. Fungicides are meant to be preventative not curative. 2) If you are in an area that received lots of moisture and did not apply a T1 fungicide then a T2 may be a wise investment. 3) You have a variety that is highly susceptible to stripe rust and the potential for stripe rust is high. Now saying that, reports indicate stripe rust is still in Southern Illinois. No stripe rust has been found in Ontario yet, but keep a close eye out for it, in favourable conditions it will spread like wildfire.

Before applying a T2 fungicide make sure to read and follow the label and consult with your fungicide supplier as some products should not be applied once the wheat is in the boot stage. When scouting your wheat you notice the wheat is well into boot stage or you have heads emerging and the field looks clean for disease, I would suggest holding off on the T2 and waiting for the T3 timing. In place of the T2 application, a wise investment of time and money would be in a good scouting program to assess and monitor fields for disease and insect pressure. If you are in the boot stage and feel disease pressure is high or conditions are favourable for disease development then make sure you use fungicides that do not contain the strobilurin mode of action. Protecting the flag leaf is critical, it is the power house of the plant responsible for a large portion of the yield, you do not want it damaged or sick during the grain fill period.

When the time comes to do your T3 application there are certain steps that need to be taken to ensure the job gets done right. As a quick reminder, below are Tim’s Tips for T3 from last Junes Wheat News Plus article.

  • The flowering wheat plant is at a very sensitive stage.  Every effort needs to be made to ensure that the sprayer is thoroughly rinsed before loading up your T3 products.  Don’t forget the inductor, agitation lines, and end caps on spray booms.  Use a tank cleaner agent also.  Be especially careful if your sprayer sat idle for a length of time before loading for T3.  Many of the other herbicide chemistry will stick to the rubber lines of sprayer.
  • Use LOTS of water 18-20gal per acre.  The target is every side of the head!  Paint the heads from every direction.  Forward/backward tips are a must, and adequate coverage is key.
  • If threatening weather is in forecast, better to apply the product at a slightly early stage instead of late, in my opinion.  Refer to your fungicide supplier for timing assistance or resources.  Early Flowering stage is the optimum timing (Day +2 to Day +4).
  • EVERY ACRE deserves a T3 spray.  You will realize an advantage.  If you don’t believe us, leave a small check strip to compare.  You will never regret protecting your crop at this stage.
  • In addition to the FHB protection, T3 fungicide application adds yield in grain, and also adds yield of cleaner brighter straw.
Forward/backwards fungicide tips for fusarium head blight management *This was only water to show tip pattern, not T3 application*
Forward/backwards fungicide tips for fusarium head blight management *This was only water to show tip pattern, not T3 application*

The DONcast® model from Weather INnovations Consulting LP is a great predictive tool to help determine the DON level potential in winter wheat throughout Ontario. Remember this tool is just a guide; the weather during flowering is what dictates FHB (fusarium head blight) and DON levels. I know in some parts of the province we have not seed FHB for the last couple years, but remember FHB should still be the most feared disease by Ontario wheat producers.

If you would like more information on T3 application information check out the link below

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