DuPont Pioneer agronomists talk about soybean aphids, fungicide applications, weed resistance and corn rootworm pressure in this July issue of Walking Your Fields newsletter. Articles are written by DuPont Pioneer agronomists in Minnesota and are distributed on behalf of DuPont Pioneer account managers and Pioneer sales reps.

1. The Good: Since last issue, crops have made some re-
markable advancements due to warm and sunny weath-
er. Many fields have turned from yellow to green which is
a good sign that roots must have gotten into the “grocery
store” (fertilizer) and are responding. The Bad: Many
fields that were caught in the May 25 – June 5 period that
received from five to 11 inches of rainfall have struggled
due to water logged conditions. The Ugly: Uneven, satu-
rated areas
of fields
need some
drier weath-
er so roots
can estab-
lish proper-
ly. Roots
need oxy-
gen to de-
velop and
move down-
ward. Side
dressed nitrogen would also help to salvage the season
in those areas of anemic, yellow colored corn. It is not
too late to apply 10 -15 gallons of 28 or 32% liquid nitro-
gen with a high boy applicator with drip tubes to keep the
solution from burning leaves.
Soils with low organic matter levels and water satu-
rated fields will benefit from planned or rescue top
dressing of nitro-
gen and sulfur.
Typically the big-
gest response oc-
curs when applica-
tions are done be-
fore the corn is 12-
18 inches tall.
However, weather
conditions forced
some later applica-
tions this year. Of-
ten 30-50 pounds/
acre of supple-
mental N is ade-
quate to offset lost
nitrogen.
GDU and Precipitation Updates.
Visit www.Pioneer.com for the latest agronomic and
weather information. Click on the “Agronomy” tab and
look for the GDU or Precipitation calculator tab. Type in
your town or zip code for local data. This website has a
wealth of agronomic information right at your finger tips. If
you need help navigating in this site, contact your local
Pioneer®
sales rep or account manager.
The information in the table above is from our Pio-
neer.com GDU calculator. We used May 1 as the starting
point. Of course if you planted earlier, your crop is further
along than indicated. GDU wise, we are not doing all that
badly. With our new Pioneer®
Field360™ Select, you
can play out scenarios where the calculator will actually
peg maturity for each of your mapped fields based on
planting date and using the average growing degrees so
far this season, it will estimate when each Pioneer®
brand
hybrid you planted will be physiological mature (PM).
Once pollination occurs, PM will be roughly 55-60 days
later. Pollination is right around the corner. Excessive
heat (especially high nighttime temps) can be detrimental
to kernel development and ear fill.
WALKING YOUR FIELDS® newsletter is brought to you by your local account manager for DuPont Pioneer. It is sent to customers throughout the growing season,
courtesy of your Pioneer sales professional. The DuPont Oval Logo is a registered trademark of DuPont. Asana® XL and Assure® II are trademarks of DuPont. PIO-
NEER® brand products are provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents. ®, TM, SM Trademarks and
service marks of Pioneer. Authority® is a registered trademark of FMC Corporation. Flexstar® is a registered trademark of Syngenta Crop Protection. © 2013 PHII.
Summer Marches Along: Crop Progress
WALKING
YOUR FIELDS
®
www.pioneer.com
July 24, 2013 - Issue 4
Table 1. Growing Degree Units (as of 7/15/13)
Location
Precip
Depart
from Norm
Since
4/1/13
GDD
Totals
Since
5/01/13
GDD
Depart
from
Norm
Montevideo -1.97 1145 -55
Hutchinson -0.53 1151 +57
Olivia +0.44 1125 +20
Willmar -2.16 1254 +147
Lamberton +5.88 1160 +12
Marshall -1.96 1168 +26
Redwood Falls -0.19 1171 -73
Worthington -0.07 1130 0
North Mankato +0.95 1172 -25
Waseca +7.06 1022 -126
Winnebago +3.52 1173 -18
www.Pioneer.com
Photo: DuPont Pioneer
Nitrogen and sulfur topdressing were criti-
cal this year with the excess precipitation.
Photo: Clyde Tiffany, DuPont Pioneer

2. Goss‟s wilt is showing up again in corn fields across the
central U.S. In 2012, the disease was found throughout
much of the area despite the dry conditions in late sum-
mer and fall. Luckily, incubation was not severe with the
drought keeping pressure in check.
The prolonged
wet weather
this spring is
conducive to
bacterial dis-
eases in many
crops, and corn
has been no
exception.
Goss‟s wilt is
caused by a
bacterial patho-
gen and doesn‟t
respond to treatment with fungicides. It is best managed
with resistant hybrids and sound cultural practices like
crop rotation and more aggressive tillage.
Signs and Symptoms of Goss’s Wilt
 Long, water-soaked, grayish-green patches or streaks
that turn to large dead streaks with wavy margins
 Dark „freckles‟ within or just outside of leaf lesions
 Lesions appear to spread along leaf veins
(characteristic of bacterial disease)
 Yellow-orange bacterial ooze (or dried ooze appearing
as shiny flecks)
 Stems may become plugged with bacteria, vascular
bundles appearing orange to brown.
The disease generally starts from inoculum surviving on
previous (corn) crop residues, found at or near the soil
surface. Early-season rainfall, especially when heavy or
associated with high winds, can lead to infection of the
young corn crop. Early infection can produce the most
devastating symptoms, including wilting and early plant
death. Later infections typically affect leaves primarily, but
may lead to early maturity, or reduced ear size and lower
yields depending on the area affected and time of symp-
tom onset.
Fungicide applications on hail damaged plants are only
recommended if there are significant fungal diseases pre-
sent. Fungicides are effective tools for protecting yield
potential of plants if significant disease levels are present
but do not improve the yield potential of crops. Other pos-
itive yield responses result from hybrid susceptibility and
previous crop history (corn on corn) and tillage practices.
Soybean aphids are right on schedule and are being re-
ported in parts of southern Minnesota. Even if you plant-
ed soybean seeds treated with a nicotinoid insecticide to
delay aphid population establishment, you will still want to
scout your fields for this pest from V5 through R5.
Symptoms. Aphid-infested soybean plants may look sim-
ilar to a potassium deficiency: curled leaves, often yellow
on the outside. Aphids produce a sugary excrement,
known as honeydew, on leaves, which promotes soot
mold growth and can serve as a feeding ground for ants.
Plants infested by the soybean aphid will also appear
shorter.
Take Action. Count the number of aphids on 30 to 50
plants throughout the entire field and calculate the aver-
age number of aphids per plant. If aphid populations
reach 250 per plant and are increasing during the R1 –
R5 growth stages, consider a foliar insecticide to control
the population. DuPont™ Asana®
XL insecticide is a
proven insecticide that gives good residual protection
against aphids. Your local authorized Pioneer sales rep
can help with product recommendations. There are also
several beneficial insects that feed on soybean aphids
and can naturally control them as well.
We have seen an assortment of carryover issues on soy-
beans earlier this spring due to the dry 2012 season
where herbicides did not break down. Most of issues
have been resolved with more adequate rainfall in 2013,
but some yield reduction is still a possibility.
Weed Resistance. More growers are reporting difficult to
control weeds. When we observe waterhemp plants sur-
viving 40 ounces of glyphosate and 12 ounces of
Flexstar®
herbicide that raises a red flag. What herbicide
options remain for these larger weed species? You may
not like the answer, but cultivation is still a viable option if
all other avenues of weed control have failed. You must
start using some kind of pre-emerge program in 2014.
Those of you who have been using pre-programs are
reporting very good to excellent control with few weed
escapes and
resistance is-
sues. The picture
here shows the
value that a pre-
emerge herbi-
cide can provide
in combatting
waterhemp and
other difficult to
control weeds.
This grower left a
“check strip”
where the spray-
Foliar Fungicide Applications on
Damaged Crops?
Soybean Aphids
Weed Resistance Concerns & Cautions
Photo: Jim Boersma, DuPont Pioneer
Photo: Pioneer Customer Using Field360 Notes

3. er boom missed this spot in the field. In this field the Au-
thority
®
herbicide did a great job keeping heavy weed
pressure at bay. Imagine if that entire field was overcome
with waterhemp and or Lambsquarters. This is happening
in Illinois, and states just south of us. Do not leave the
blinders on and ignore these warnings. Weed resistance
could be coming to a field near you!
Parts of Minnesota and South Dakota saw extreme west-
ern corn rootworm pressure in 2012. Extended corn after
corn rotations had the biggest issues. Scout fields in the
coming weeks as the 2013 CRW hatch has begun with
young larvae now being observed. Hopefully the severe
winter, along with the cold and wet spring have caused
higher egg mortality. However, we won‟t know for sure
until August. Dig up roots and immerse the whole root
mass into a bucket of water. Swish the root ball in the
bucket to dislodge the CRW larvae. A cup of Epsom salts
in this solution makes the little larvae float to the top. Your
local Pioneer sales rep or account manager can assist
you with root digs.
Control volunteer corn as this can attract CRW beetles.
They mate and lay eggs in heavy volunteer corn growing
in soybeans. Crop rotation is a good management tool
that is effective against the western corn rootworm spe-
cies. Remove any volunteer corn from soybean to pre-
serve this rotation asset. DuPont™ Assure®
II herbicide
controls volunteer corn in soybeans.
Avoid spraying glypho-
sate past the R2 stage
in soybeans. Many
growers will spray a last
shot of glyphosate when
soybeans are well past
the R2 stage. This can
cause flowers and early
developing pods to be
aborted, which reduces
yield. Herbicide timing is
very important. Poorly
planned herbicide appli-
cations can negatively
affect the plant‟s physio-
logical processes.
New sales area KS creates new positions and new
assignments. Pioneer continues to go through a stage of
rapid sales growth. There were some personnel changes
that became effective June 1, 2013.
Jim Boersma, previously a product agronomist, has
been assigned back to his previous field agronomist posi-
tion to cover the northern and eastern part of area KH.
Clyde Tiffany remains a field agronomist and has ac-
cepted a position in the newly formed KS sales area
which encompasses central Minnesota and western Wis-
consin.
Dave Pfarr, formerly a field agronomist, has taken on a
new role as NBU soybean services & stewardship man-
ager.
Neil Hansen accepted the field agronomist position, re-
placing Dave Pfarr. He was previously an account man-
ager in Jackson and Cottonwood Counties.
Brad Weber remains an account manager, but his territo-
ry in now managed by the KC sales area manager.
Kevin Jones accepted the account manager position
vacated by Chad Galles. Kevin will have sales responsi-
bilities in Watonwan and Martin Counties.
Mark Navara accepted an account manager position in
the newly formed KS sales area in northeast Minnesota.
As always, our team is here to provide you with world
class agronomy information and service!
Pioneer Field360 Notes pinpoints your field location
via satellite imagery so you can record notes or photos on
the spot.
 Displays field boundaries for DuPont Pioneer custom-
ers
 Easy to use interface; compatible with Apple and An-
droid Systems
 Instantly map and organize data with notes and photos
 Share your data from the field via email capability
Pioneer®
Field360™ Select software is an interactive,
web-based subscription service that combines your field
data with real-time agronomic and weather information
 Track field by field Precipitation and GDUs using Field
360 Select
 Scouting 101 with GPS located as-planted Products
 On-The-Go organized field applied data
 Satellite imagery pilot program in 2013
Contact your local Pioneer Professional for more Info!
Evaluate Corn Rootworm Technology
Updates to the DuPont Pioneer Team
Photo: DuPont Pioneer

4. WALKINGYOURFIELDS®
KH Gubrud, Lensing, Boersma, Hansen
DuPont Pioneer
Sales & Marketing
PO Box 466
Johnston, IA 50131
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