Crop Watch
Field observation
The common observation
made by most ag people is
that they have never seen the
corn crop grow so fast in a
short period of time as the
plants did this year. Getting
25 plus GDUs per day for
about two weeks will cause
very rapid growth. Will the
stalks be as strong this year
or might they be weaker?
We could see a difference
versus normal, and soil test
levels for Ca and K could be
an influencing factor.
In many fields in central
Iowa the plant have reached
the late V4 moving into the
early V5, which is when
rapid growth occurs. This is
also when the cautions about
using phenoxy are justified.
It seems that more corn
growers are using Dicamba
based products on corn to
take care of some of the
problem broadleaf weeds.
This was reminiscent of the
time when farmers would
wait until about May 15th
before planting beans, so
would begin spraying corn
before the beans emerged.
They knew their drift or inversion
problems were minimized
if very few beans
were emerged in their neighborhood
at the time of
Dicamba applications.
Rainfall
Early in the season the
daily amounts of precipitation
used by the plants is
very small. As the plants
grew from the V6, and later
the V8
stage the
daily usage
will
increase,
peaking at
tasselling
time.
Stored and
immediate
moisture
typically
meets
those daily
requirements thru April
and May. Then as root uptake
increases the immediate
demand for moisture is typically
met by rainfall.
Insect indicators
The first fireflies are beginning
to appear now and
their little lights can be seen
blinking at dusk. Concurrent
with their appearance is our
normal CRW egg hatch.
This typically takes place
when 720 to 730 GDUs
have accumulated. So depending
on location within
the north/south heat unit
charts expect the first root
feeding to start. This is a labor
intensive process that
normally involves a spade or
sand shovel, buckets and a
good higher pressure hydrant.
It takes time to wash
off the roots to look for feeding
damage, and even more
time and patience to find the
very small larvae.
And if you do find them
the appropriate question is
what could be done to remedy
the problem. In the past
we have seen the Neem oil
based Safe Strike diminish
the amount and rate of root
feeding. Sometimes the
small black headed larvae
move off the roots and quit
feeding. I am curious and we
will be seeing if the Chitosan
based products could cause a
halt to the feeding.
Another insect that has
been seen are the slow flying
medium-small flies that
move quite slow and don’t
move much when you begin
swatting them. These are the
adults of the seed corn maggots.
They often feed on the
disked under vegetation of
small grains or weeds as the
fields were worked. I have
seen where they tunneled up
the stem of just emerged
soybeans causing them to
topple over. It takes a keen
eye or a good magnifying
glass to see the small
translucent larvae.
The bean leaf beetle numbers
were high in the first
planted fields, but now as
more fields have emerged
those populations have drifted
down to where no fields
meet the established thresholds.
Look for the holes in
the leaves and approximate
the percent of the tissue lost
to feeding.
Herbicide happenings
Two weeks ago it was
tough to find many weed
seedlings in the fields. That
is no longer the case, as there
are high counts of our common
weeds in many fields
where control was less than
expected with about six
common broadleaves.
There have also been cases
where the PPO used last
season appears to have carried
over. Expect to see
stunted, yellowed plants.
They typically survive, but
grow and develop slower.
As to the cause (s) some of
the herbicides could have
been applied after the July
1st cutoff date or the drier
conditions after application
slowed down the expected
degradation.
Show me the money
plot and field day
Several of us drove thru
and took video of the plot
work being done at the
Guthrie Center research
farm on Saturday. The corn
was planted later than in the
previous seasons and was
now close to the V4 growth
stage. It looked very good.
There is an area where a
variety of inputs are being
applied in tandem or in sequence
to see which ones influence
the yield or other
traits the most. We took a
stair-step approach to see if
each pair of input products
was producing just an additive
effect or offered a multiplier
effect. For instance 1 +
1 should equal 2. But if they
equal 3 or 5 enough to be
significant, then they could
offer growers a high ROI.
When we are using several
new products the challenge
can be identifying the
product or series of products
that should receive the credit.
We expect to have a plot
showing and meeting down
at the farm around Aug 20,
or before farmers get busy
with harvest. Our March
12th meeting in Ames that
was attended by 120 note
taking growers told us that
growers were interested in
getting educated and hearing
new ideas that seem grounded.
In the meanwhile we are
assembling the BioEmpruv
and Argosy that will be applied
this week and can be
expected to keep the plants
alive, healthy and filling until
mid to late October. We
will also apply the Take- Off
signaling compound from
the Los Alamos Lab that
seems to be working well in
all crops. The Calcium silicate
product is also in the
shed and ready to be applied.
If it allows the corn plants to
be more stress tolerant and
get by with 30 percent less
water while also increasing
the RUE (radiation use efficiency)
, the boosted sugar
production should form
more bushels.
We also have the liquid
poly peptides that are giving
good results in Brazil. The
same goes to the Ensure
product, which boosts heat
and drought tolerance
tremendously. All of these
things should help build on a
fertility program that is built
on soil health and balanced
fertility which is accessed
thru the use of Verdesian
fertilizer stabilizers. This is
all good and we are expecting
big things. It can still be
a case that in the end we will
have the answers but might
wonder what some of the
questions are. But that is
how science and producers
can make significant advances.
Soybean growth
Most of the soybean
plants are now in the V2 to
V3 growth stages. In a week
it will be time for growers
who wish to increase their
bean yields to begin their foliar
programs. The goal is to
influence their architecture
and change their physiology
to form more roots, more
side branches, added pods,
shorter internodes and
stronger stems. Past yield
winners have a game plan
set up and typically follow
thru with it, adding a few
new items as their knowledge
base expands. What are
you doing different this year
to get better?
Bob Streit is an independent
crop consultant and columnist
for Farm News. He can be
reached at (515) 709-0143 or