The answer to this question is a definitive yes! The impact upon regional rootworm pressure
will be dramatic. University specialists
fully expect rootworm pressure within our footprint to be as low as it has ever
been. The likelihood of an individual
field suffering rootworm injury in 2016 decreased drastically this season.
We previously mapped out the reasons
why rootworms will be less prevalent throughout the Burrus footprint in2016.
Does that mean we will not see any
issues in 2016?
Common sense says this cannot
possibly be the case. Nobody can
guarantee zero rootworm pressure and nobody can guarantee zero rootworm injury. There are too many qualifiers.
One
of those qualifiers comes in the form of varied rainfall. Rainfall totals varied across the Burrus footprint.
The I-80 corridor provides dramatic evidence.
The eastern portion of that corridor suffered severe crop injury as
rainfall transformed fields into swamps.
The western portion received rainfall at just the right rate resulting
in a beautiful crop. Rootworm
suffocation would have been an issue toward Kankakee County, but it was a
non-issue in Rock Island County. While
much of the Burrus footprint will experience less pressure due to 2015
rainfall, this will not be the case in every region. There will likely be variation even within
saturated regions of the Burrus footprint.
Suspected rootworm root injury near Woodstock, IL |
The
second qualifier relates to the subject of rootworm species. Even though overall rootworm pressure decreased
in 2015, beetles were not completely absent.
Burrus noticed more Northern corn rootworm beetles this season than we
did Western corn rootworm beetles. This
gave us pause. We know that Northern
corn rootworm beetles, particularly those in the northwest part of our
footprint, have occasionally displayed extended diapause (a habit of
overwintering eggs for more than one year).
We noted, in this article, that rootworm eggs tend to survive pretty
well in saturated soils (mortality increases in cool, wet conditions but it
does not completely zero out rootworm eggs).
What if some Northern corn rootworm eggs displayed extended diapause and
made it through 2015 unscathed? While a
remote possibility, it is still a possibility.
These qualifiers keep us from boldly
predicting no rootworm pressure in any field in any corner of the Burrus
footprint. We can state with confidence
that rootworm pressure will be much less likely across the Burrus footprint –
but we dare not proclaim that it is a complete non-issue in 2016.
What should be our
strategy going forward?
The 2015 growing season was
incredibly hard on crops. Despite some positive
harvest surprises, nobody wants to see a season like this again. It was gut-wrenching. However, excessive rainfall may have a silver
lining associated with it. Excess
rainfall might have acted as a rootworm “reset button” in many fields. Our best management efforts could never drag
rootworm pressure to 2016 lows. Mother
Nature did what our technology was incapable of doing. Think of this year being a magic wand. When it was waved over our fields, it pulled
many fields back from the edge of resistance.
It did not eliminate resistance concerns, but it did provide us some
resistance breathing space. We may have
increased the chances that we can beat this thing.
Burrus
has encouraged growers to rotate traits each growing season. If they have been relying on only one trait,
we have encouraged them to move away from it.
We have encouraged them to use alternative traits in the Burrus
lineup. That recommendation is still sound. We know it will help us prolong trait life
because “it will keep resistance off its’ game.” Many growers have been
hesitant to embrace that recommendation though.
“What if I shift to a different trait and it doesn’t work?”
It is always more comfortable to
stay with the familiar, especially when you believe the risk is high. We do not believe that risk really is high,
but after this season, growers should realize that the risks associated with
trait rotation are lower than ever before.
There has never been a better time to try a rotation to new traits.
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