The Importance Of Late Season Wheat Investments

  Mid-West Fertilizer 

In our geography, we're no stranger to the array of late season diseases that we face as wheat growers. Before you decide to skip a late season fungicide application, here are some things to consider.

Protecting the Flag Leaf
Flag leaf is the most important stage for grain fill, as that top leaf is responsible for harnessing more than 50 percent of the plant’s photosynthetic power from the sun. About half of your wheat stand’s yield potential is determined at this point, so if a disease like powdery mildew, stripe rust or tan spot, etc. takes out half of your flag leaves, you can lose a quarter of your crop’s yield potential. Absolute Maxx SC®, Topaz®, Stratego YLD® and Headline® are popular fungicides for flag leaf applications.
Farmers have long known that a well-timed fungicide application might provide a good return on investment when conditions are favorable for disease development. But the problem has always been scouting to decide if an application is warranted and then spraying within a small window to achieve adequate protection – specifically when the flag leaf is 50 percent to fully emerged. Historically, farmers have often skipped this application because they’re busy with other work at this time, and they know they’ll have to make another fungicide pass at heading as little as two weeks later.
Fusarium head blight (head scab) at heading can cause significant yield losses and quality reductions, so it’s important to consider how your wheat varieties stand up to the disease and whether conditions are favorable for its development. If your varieties are susceptible to head scab and wet, humid conditions are present at heading, a fungicide treatment has a higher potential of providing a better return on investment than it would on tolerant varieties in dry conditions.
Accurately timing this fungicide treatment can be more challenging than at wheat’s other growth stages, because you need to target application within a few days of flowering. Spraying at 10 to 15 percent flowering tends to provide the best results. Triazole options like Onset® 3.6L fungicide by WinField United or Prosaro® and Caramba® fungicides provide good protection against head scab. Strobilurin fungicides should not be used once the head is fully emerged because they can elevate DON (vomitoxin) levels, which can lead grain buyers to charge dockage fees.
Deciding if and when to spray isn’t the only challenge when it comes to fungicide treatments. Another is to achieve good coverage – especially when spraying contact fungicides – so make sure you have adequate water volume and use a nozzle that sprays medium-sized droplets. Also use a canopy-penetrating agent like InterLock® or MasterLock®adjuvant from WinField United for better spray deposition, improved coverage and reduced off-target drift.
Be sure speak with your local Mid-West Fertilizer Agronomist if you have questions about application equipment or timing. Most importantly, if you have a history of certain diseases in your wheat fields, we'll be able to recommend the right fungicide and adjuvant package for the job.

To read more about various wheat diseases CLICK HERE.