This July issue of Walking Your Fields newsletter contains articles about: soybean pests and diseases, the benefits of cover crops and the causes of corn root lodging. Articles are written by DuPont Pioneer agronomists in southeastern Minnesota and are distributed on behalf of DuPont Pioneer account managers and Pioneer sales reps.

1. Southeast Minnesota is excited to have Josh Shofner join
the agronomy team. Josh spent the past two years as an
Account Manger for DuPont Pioneer in SE Minnesota.
His new role as Field Agronomist replaces Ryan Bates
who accepted the Field Agronomist position with Pioneer
in Western Wisconsin.
Soybean aphids are right on schedule and were recently
reported in southern Minnesota. Even if you planted soy-
bean 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.
The soybean aphid overwinters in buckthorn and mi-
grates to legumes (soybeans, alfalfa and clovers) in July.
It’s less than 1 mm in length but when left untreated, eco-
nomic infestations can reduce yields by more than 10
bushels/acre.
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.
Besides a stunted plant with noticeable discoloration, you
can also detect these
oval-shaped, light
green pests with
black ―tail pipes‖ near
the end of the abdo-
men by doing numer-
ous sweeps through
the field.
Take Action. Count
the number of aphids
on 30 to 50 plants
throughout the entire
field and calculate the
average number of
aphids per plant.
If aphid populations
reach 250 per plant
and are increasing dur-
ing the R1 – R5 growth
stages, consider a foli-
ar insecticide to control
the population. Your
local Pioneer sales rep
can help with product
recommendations.
There are also several
beneficial insects that
feed on soybean
aphids and can naturally control the aphid population.
They include Asian lady beetles, damsel bugs, green
lacewing larvae, and insidious flower bugs.
White Mold (Sclerotinia Rot) - Sclerotinia white mold is
favored by cooler night temperatures (50-60°F) and moist
conditions in the plant canopy. In addition to cool temper-
atures, the production of white mold apothecia
(mushroom-like structures) requires moist soil and a
closed canopy. If surface soil moisture is low or the soy-
bean canopy is not closed during flowering, the fungus
would not be able to produce apothecia. When scouting
for this disease, pay attention to the fields that had white
mold previously and that have good soil moisture and a
closed canopy. The first
evidence of white mold is
a chlorotic, girdling lesion
covered with white, fluffy
mycelium at one of the
middle nodes. The evi-
dence of the disease be-
comes conspicuous in
August when dead tops
start to show up in fields.
White mold is a disease of
high management. It is
most likely to show up in
low spots of the field,
where plant populations
are high, in narrow rows,
in tightly closed canopies,
where plants become
lodged and/or where less
tolerant varieties are
planted.
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. PIONEER® 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. © 2013 PHII.
New Team Member
WALKING
YOUR FIELDS
®
www.pioneer.com
July 24, 2013 - Issue 4
Photo by Josh Shofner and Brian Buck
7/5/13
Photo:DuPontPioneer
Soybean plant showing symptoms
of white mold.
Soybean Aphids
White Mold (Sclerotina Rot)
Photo: Marty Lovrien
Soybean aphids and an ant on under-
side of soybean leaf. Aphids excrete
―honeydew,‖ a sugary substance that
attracts other insects and also results in
development of sooty mold.

2. SCN race shifts and high cyst counts are an added
stress to soybean fields. Planting SCN-resistant soy-
bean varieties that include the Peking and PI88788
source of resistance, along with rotating to a non-host
crop are two of the best ways to prevent SCN infesta-
tions. Extension specialists have advised that overuse of
any single source of SCN resistance can lead to SCN
race shifts over time. Therefore, it is important to switch
between varieties and always scout fields.
To scout for SCN, dig up soybean roots and gently wash
the soil away. If you don’t see a high number of SCN,
recheck in two weeks to make sure you are not between
production cycles.
DuPont Pioneer offers both the Peking and the
PI88788 source of resistance. Take time to dig and
compare the female cysts numbers between the Peking
and PI88788 sources.
When SCN becomes prevalent, it also promotes the de-
velopment and spread of Sudden Death Syndrome and
increases the severity of Brown Stem Rot.
Below are recommendations from the Plant Health Initia-
tive funded by the Soybean Checkoff on crop and soy-
bean resistant variety rotation:
 Rotate with non-host crops to reduce SCN numbers.
 Rotate with resistant soybean varieties to reduce yield
loss due to SCN.
 Rotate the resistant varieties you use: don’t use the
same one twice in a row.
 Rotate with tolerant or susceptible soybean varieties
only if SCN numbers are low.
More information about SCN resistant varieties and SCN
damage is available through you local Pioneer sales rep
and also available in the Soybean Cyst Nematode Man-
agement Guide: http://www.planthealth.info/pdf_docs/
SCNGuide_5thEd.pdf
A quick trip across southern Minnesota countryside re-
veals that many growers are in the same boat this year
with flooded land and partially or completely unplanted
fields. When possible, these growers should consider a
cover crop instead of letting fields sit fallow all season.
Significant damage can be done to the soil’s biological
properties by leaving unplanted fields bare, fallow, during
the growing season. Research indicates that the effects
of a bare field carryover into the next growing season
with phosphorus (P) deficiencies and ultimately could
decrease yield, especially in corn. Fallow syndrome, as
this condition is known, occurs when planted fields flood
or fields are left unplanted. Crops planted on that ground
the following year may show signs of P and zinc (Zn) de-
ficiencies, severe stunting, uneven emergence, irregular
stands, purple or light green colored leaves and poorly
developed roots.
When no vegetation is planted, there is a reduction of soil
vesicular-arbuscular mycorrhizae (VAM) fungi. VAM fungi
are found around plant roots and help in the uptake of
nutrients from the soil, along with increasing the plant’s
tolerance to heat and drought. The fungi can be hundreds
of times longer than plant roots and significantly extend
the absorption zone of the root system. VAM fungi need
host plants to complete their life cycle and without a
growing crop during the season, the fungi will not be pre-
sent for the following growing season.
Cover crops have numerous benefits to the soil:
 Prevent Soil Erosion
 Soil Structure Improvement
 Nutrient Storage
 Water Infiltration
Soybean Cyst Nematodes
Why Cover Crops on PP Acres
Photo: DuPont Pioneer
Female cysts of SCN on plant roots.

3. Extreme, early-season moisture, strong wind events and
corn rootworm feeding all contribute to increased poten-
tial of corn root lodging. If root lodging has occurred, take
time to assess the cause of lodging—don’t just assume it
is rootworm feeding.
Causes of Root Lodging in Corn
 Wet conditions at planting, causing sidewall compaction
and restricting root growth
 Wet conditions early in the growing season
 Strong wind and rain events during critical root develop-
ment and prior to brace root formation
 Reduced root growth due to nitrogen deficiency
 Hybrid differences in root formation
 Corn rootworm (CRW) feeding
Yield loss and lodging due to CRW feeding is affected by
the timing of root feeding, weather, soil type and hybrid
type. Extreme root lodging often results from root feeding
by CRW larvae in June, followed by summer storms.
Once rootworm larvae have damaged or destroyed roots
near the soil surface, they work their way down the root
system. The later the root lodging occurs in the growing
season, the less able corn is to straighten up without pro-
nounced goose-necking. Closely monitor root lodged
fields and consider harvesting at higher moistures, if stalk
rot becomes an issue.
Once corn hits pollination it takes about 55-60 days to
reach physiological maturity. Most 100-105 day CRM
hybrids pollinate around 1250-1300 GDDs. An 80 day
hybrid would be around 1000 GDDs. We have had the
heat needed to keep the crop going up to this point and
the forecast also looks good! For example, if we average
highs in the low 80s, say 82, and lows in the low 60s, say
62, the average GDUs collected per day would be 22.
Doing the math below based on when you planted we
should be pollinating at a reasonable date for much of the
corn planted throughout SE Minnesota!
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
 Scouting 101 with GPS located as-planted products
 On-The-Go organized field applied data
Pioneer Field360 Notes pinpoints your field location via
satellite imagery so you can record notes or photos on the
spot.
 Displays field boundaries for Pioneer customers
 Easy to use interface; available for iOS and Android™
 Instantly map and organize data with notes and photos
 Share data from the field via email
Contact your local Pioneer Professional for more Info!
Root Lodging in Corn Corn GDU Update
Photo: Marlin E. Rice
Corn rootworm damage reduces a plant’s structural support and
makes it more susceptible to lodging. CRW injury to nonBt corn
roots on left compared to Bt hybrid on the right. Taken from an
Iowa State University research plot.

4. WALKINGYOURFIELDS®
KC Lensing, Buck, Shofner
DuPont Pioneer
Sales & Marketing
PO Box 466
Johnston, IA 50131
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