Fork In The Road

Fork In the Road from Central Valley Ag on Vimeo.

by Mike Zwingman

by Mike Zwingman

Who knew he was talking about applying fungicides at tassel time?

There are pretty much three camps on this issue:

  • The Yes, Please’s. They want to do it and do it now.
  • The Maybe’s. They want to keep an eye on it and act accordingly.
  • The No, Ma’am’s. They don’t want to do it now.  Or ever.

Contrary to the social tenor on {insert subject de jour here}, you don’t have to pick a side.  This is a fork in the road.  So take it.

Because the best approach to applying fungicide at tassel keeps all three on the table to various degrees and for various reasons.  And the best approach behooves you: with 60 days left in the growing season (!) 75% of our crops photosynthetic capacity lies above the ear leaf.  If we’re going to optimize yield, we simply can’t compromise this capacity.  We can’t lose any due to disease, and we can’t let it slow due to stress.

From tassel time on, all we can do is lose, friends: we simply can’t create any more bushels, only save what we’ve earned so far.  Which means that we’re now defending the bed we made.  All that time, effort, care we put into getting here?  I vote that we take the best approach and preserve it.

Which is my case for all of the above.

The first perspective, to apply without question or scrutiny, is a total plant health perspective.  To go this route is to reduce total stress on your crops: to help keep stomata open longer, use water more efficiently, and reduce dark reactions (which are the other side of photosynthesis: the reactions that burn the sugar created in light reactions).

This approach gets most of the room on the table because it will return you your investment.  Check out the available ROI calculator here for proof of this point.

The second perspective, to watch and act accordingly, is an approach that most directly addresses disease.  This is an approach to be taken on marginal acres and in fields with high disease pressure where the careful timing of the application will extend the fungicides window of effectiveness against disease.

It gets some room on the table because it is a practical and effective approach to countering disease.  Beware though that this approach is more involved than the first.  Doing it well requires scouting more than once per week, keeping a careful eye toward the development of favorable disease conditions, knowing cropping history, and understanding things like hybrid interactions and other interactions in your crop’s particular ecosystem.

Which leaves the third perspective.  It’s possible that this perspective gets no room on the table in many situations, but if you find yourself with a field that simply isn’t worth throwing your money at anymore, it’s time to invoke the third option.  It’s an approach to be used sparingly, but such is sometimes our reality.

Of course, a second major question of applying fungicide at tassel is which product to use.  There are more options than I can do justice to here, but there are a few things to be said, of course.  For starters, see the attached product information chart from the Corn Disease Working Group for a good overview of your options.  Secondly, talk with your Central Valley Ag Field Sales Agronomist, who is replete with local knowledge.  Thirdly, avoid a few things:

  • Generics with only a single mode of action. Many diseases, like many weeds, are beginning to show resistance to some products.  Using multi-modal products not only increases your chances of the product working as intended and desired, but also offers us the best chance to manage resistance over time.
  • Poor application quality. The quality of an application affects a products efficacy significantly, so do it right.  That means using quality adjuvants, too.  CVA has relationships with some great aerial applicators if you need a place to start.
  • Ill-timed applications. This is important all around: applications should be made at full tassel.  Full tassel occurs when the entire tassel is out and open on at least 80% of the plants in your fields.  And once your fields hit this point, move fast, people!


And that’s that.  Easy easy, right?  For what it’s worth to you though, it’s some thought and effort well worth it.  It’s thought and effort that will defend the good work you’ve done so far, and thought and effort to help you ride out these next 60 days in style and with satisfaction.  Maybe even a bit more peace.