By Darren Hefty – darren@agphd.com

It’s amazing the things I hear in side discussions at our winter workshops.  Here’s one example I heard when I was in Idaho in January.  A grower told me, “I’ve gained a ton of yield the last 2 years following your advice to spray insecticide and fungicide on my wheat, but I don’t want to tell anyone else.  This is my competitive advantage.”

Maybe it’s just me, but that sounded a little bit selfish.  It also made me smile and laugh.  The word is getting out about the yield increases wheat farmers are seeing spraying insecticide and fungicide in-crop.  If you think about what you’re actually doing – controlling most of the bugs and diseases that could damage your crop – it makes a lot of sense.  Here’s what to look for and how to know when and if this could be right for your farm.

Diseases

  1. Prevention is key.  If you are seeing a disease in your field, you’ve given up yield and your fungicide won’t work very well.  In my opinion, scouting is nearly worthless for diseases.  Make the decision early in the growing season (or now) if you’re going to treat, and spray early before diseases set in.
  2. Rotation is also key.  Crop rotation is helpful, but don’t forget about rotating the fungicides you use.  If you use a strobilurin fungicide like Headline, Quadris, or Evito for your first application of fungicide, switch to either a combo product like TwinLine, Quilt, or Stratego or use a triazole fungicide like Orius (tebuconazole – a.k.a. Folicur) or Bumper (propiconazole – a.k.a. Tilt) for the next application.
  3. Limited protection is reality.  Since none of the fungicides move very well or last very long in the plant, you can really only protect the plant tissue that you apply the fungicide on.  For example, if you spray at flag leaf, you’re only protecting the plant from the flag leaf and down, and that’s only if you get great spray coverage and actually apply fungicide on each and every leaf.  You can’t protect the head from scab if you’re spraying before the head has emerged.  For this reason, multiple applications throughout the year are needed.

Insects

  1. Diversity – While there may not be enough of one certain species of harmful bugs in your wheat to justify treating with insecticide, there likely are multiple species at lower levels.  Take a sweep net or even a ball cap to the field and sweep it through the crop a few times before making any insecticide application.  If there are a good number of harmful bugs, spray.  If there are no bugs, do not spray insecticide.
  2. Combination application – The reason we see the best results applying fungicides and insecticides at the same time is much like the reason you wash and bandage cuts on your skin.  Any open wound created by an insect leaves your wheat vulnerable to an infection.  Stopping the bugs and protecting the wounds at the same time has shown a great ROI (Return on Investment) for those who have been doing it.

Timing

We recommend considering a fungicide/insecticide application at three critical times during the season.

  1. Herbicide timing – Early-season protection is critical to set the table for high yield potential.
  2. Flag Leaf – Of all the times to protect your crop from bugs and diseases, this may be the most important.
  3. Heading – While there are better options available, a full rate of Orius (fungicide for stripe rust and head scab protection) plus a full rate of a pyrethroid insecticide will likely cost about $2 per acre each.  That’s much less than the value of a single bushel of wheat.  For that price, why take a chance leaving your crop unprotected?