The Wheat Teams T3 Tips

Factors to consider for effective T3 applications

In the coming days the southern end of the province will be well into T3 applications. With warm temperatures in the forecast, those with wheat in the boot stage will move quick. The risk of FHB is highest when the wheat is flowering and there are heavy dews, fog, rain, high humidity with warm nighttime and daytime temperatures. There is lots of great information out there for timing and application effectiveness. Be sure to check out the archived videos on the Wheat School website if would enjoy some more detailed information.

Every year we talk about “days” with regards to flowering stages and fungicide timing, but what does this mean? Depending on temperature there could be a seven day window to apply T3 products. Some years it is longer than seven but some years it is shorter than seven. Being ready to spray and carefully watching the crop is the most effective way to determine when to spray.

Day – means the number of days prior to heading.

Day -3 (GS 49) The first awns are just visible at the top of the boot. You are roughly three days away from heads being completely emerged from the boot.

Day + means the number of days following heading.

Day 0 (GS 58) head is completely emerged, but no flowers are visible yet.

Day +1 (GS 60) beginning of pollination. Anthers will start to be visible on the head. The flowering always starts in the middle of the head.

Day +3 (GS 64) The head is half pollinated

Day +4,+5 (GS 68) depending on the weather the heads could be fully pollinated by this point. Some late tillers may still be flowering.

Day +2

Here is a supplemental list of other timely considerations for getting this job done.

-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. Use tips that produce coarse to very coarse droplets. Nozzles that produce medium/fine droplets tend to create a “fog” which with any amount of wind will blow around and not “paint” the head.

Forward/backwards Spray tips

-If threatening weather is in forecast, it is better to apply the product at a slightly early stage instead of late.  Refer to your fungicide supplier for timing assistance or resources. The early flowering stage is the optimum timing (Day +2 to Day +4). If conditions do not allow applications to be made during the optimum window and you are worried you are too late there is still value in applying (day +5, +6, +7) if conditions are conducive for FHB. If anthers remain on the head, spray!

-For maximum efficacy of T3 fungicides, you want to aim for 50% flower on at least 75% of the heads in the field

-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.

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. We know in some parts of the province we have not seed FHB for the last number years but remember FHB should still be the most feared disease by Ontario wheat producers.

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