Soybean Insect Pest
Management - 2009
Phillip Roberts and Bob McPherson
University of Georgia
Soybean IPM
Scouts / Consultants
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Offers great value to growers.
Must know insect pest populations and
species makeup to make Good Decisions.
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Economic Thresholds
Insecticide Selection
Timing of Applications
Evaluation of Sprays
Early Detection of Potential Problems
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Insects/Weeds/Fertility/Diseases/etc.
Lesser Cornstalk Borer
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Understand Risk
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Hot and Dry
Late planting
Burnt residue
Preventive treatment
Rescue (POST) treatment
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Difficult to control established infestations
Common Pests of Soybeans
Foliage Feeders
Common Pests of Soybeans
(Green Clover Worm)
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Larvae have 3 pair of
abdominal prolegs
Same looping movement as
Soybean loopers
Very active when disturbed
Often attacked by a number
of parasites, predators, and
diseases
Generally not treated for
alone
Common Pests of Soybeans
(Velvetbean Caterpillar)
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Larvae have 4 pair of
abdominal prolegs
Usually very pronounced
white line but color may
vary
Very active when disturbed
Voracious feeders usually
starting in the top of the
canopy and moving
downward
May feed on petioles cutting
pods to the ground
Migratory
Common Pests of Soybeans
(Soybean Looper)
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Larvae have 2 pair of
abdominal prolegs
Larvae are tapered toward
the head
Eggs deposited singularly,
usually on the bottom side
of the leaf surface
Eggs similar to corn
earworm but somewhat
flattened
Often attacked by
pathogens
Migratory
Foliage Feeder Thresholds for Soybeans
Green
Cloverworm
Velvetbean
Caterpillar
Soybean
Looper
Avg. / 25
Sweeps
60
40
20 sm. or
15 lg.
Avg. / Row
Foot
10
8
8 sm. or 6 lg.
Prior to Full Bloom
Full Bloom-Mid Pod Fill
30%
15%
After Full Pod Fill
25%
Soybean Insecticide Trial
Midville 2007
VBC/12 row ft (5 DAT)
Untreated
Intrepid 4 ozs
Dimilin 2 ozs
Tracer 1 oz
Will not provide
consistent control
of VBC
Steward 5.6 ozs
Karate Z 1.92 ozs
Pyrethroid 0
Susceptibility?
5
10
15
20
Dimilin / Boron
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Apply at R2-R3 Stage
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Dimilin 2 ozs/acre
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Controls GCW and VBC, suppresses SBL
Long Residual
Boron 0.25 lbs B/acre
R2-Full bloom – an open flower at one of the
two uppermost nodes on the main stem with
a fully developed leaf.
R3-Beginning pod growth – pod 3/16 inch
long at one of the four uppermost nodes on
the main stem with a fully developed leaf.
Soybean Insecticide Trial
Midville 2007
SBL/12 row ft (5 DAT)
Untreated
Intrepid 4 ozs
Dimilin 2 ozs
Tracer 1 oz
Steward 5.6 ozs
Karate Z 1.92 ozs
Endigo 4 ozs
0
5
10
15
20
Soybean Insecticide Trial
Midville 2007
SBL/12 row ft (5 and 10 DAT)
Untreated
IGR is slower acting.
Intrepid 4 ozs
5 DAT
10 DAT
Tracer 1 oz
Steward 5.6 ozs
0
5
10
15
20
Soybean Insecticide Trial
Stripling Irrigation Research Park 2007
SBL/12 row ft (6 DAT)
Karate Z 1.92 ozs
Larvin 18 ozs
Tracer 1 oz
Steward 5.6 ozs
Intrepid 4 ozs
Untreated
0
10
20
30
40
Common Pest of Soybeans
(Stink bug Identification)
Southern Green / Green Stink bug
Southern Green
Photos by Herb Pilcher, www.ipmimages.org
Green
Brown Stink bug
Piezodorus guildinii
Red Banded Stink Bug
Major problem in Louisiana
soybeans, present in Georgia
(can be difficult to control).
Stink Bug Life Cycle
Southern Green Stink Bug
Egg to Adult 35-40 days
(adults may live several weeks)
Stink Bug Feeding
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Feeds primarily on
fruiting structures and
meristematic tissues.
Injects enzymes to
dissolve plant tissues.
Physical destruction of
seed/tissues.
Introduces or allows
entry (wounds) of some
pathogens and decay
organisms.
Multiple Cultivated and Wild Hosts
Landscape/Farmscape (Strong Movers)
Move from one host to another
throughout the growing season
(host suitability).
In-Field Distribution
Stink Bugs (Clumped, Edge Effects)
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A 24-acre commercial
cotton field was
sampled weekly at a
density of 20 bolls/acre
Developing bolls were
dissected weekly and
examined for internal
damage
Spatial maps were
created to visualize
damage
31 Aug 07
9 Sept 07
Common Pest of Soybeans
(Stink bug Damage)
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Most damaging during pod fill
Damage results in unfilled,
malformed or shrunken pods
Aborted pods
Trap Cropping is an
effective management
strategy.
Stink Bug Thresholds for Soybeans
Bloom-Mid Pod Fill Mid Pod Fill-Maturity
Avg. / Row Foot
Avg. / 25 Sweeps
0.33
1
3
6
*Seed bean threshold, 1 stink bug per 6 row feet.
Insecticide Susceptibility
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Southern green, green, and brown stink bugs
are the primary stink bugs in the southeast.
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Species makeup varies by location, crop, and in time.
Pyrethroids provide good control of southern
green and green but only fair control of
brown stink bugs (high rates improve
control).
OPs provide good control of southern green,
green, and brown.