1. ‘Tiny Terrors’… The Soybean Aphid NACAA AM/PIC 2007 Invasive Species:
Arrive, Survive, and Thrive
‘Tiny Terrors’…
The Soybean Aphid
Chris DiFonzo
Field Crops Entomology
Michigan State University

2. the Soybean Aphid, Aphis glycines Matsumura
Secondary host:
Glycine max
(soybean)
June
July
August
March
fundatrix
Winter
eggs
gynoparae
males
Sept
oviparae
Primary host:
Rhamnus spp.
(buckthorn)
Fall

3. General Invasion Process
Arrive
Thrive
Survive

4. ARRIVE Japan China Siberia U.S. 2000 Australia 1999
Malaysia
Philippines
Thailand
Indonesia
Siberia
U.S. 2000
Australia
1999

5. Trade and Tourists direct flights from Asia
ARRIE
Trade and Tourists
direct flights from Asia
to Detroit, Chicago, Minneapolis
- increase in goods imported from Asia

6. 2000 Discovery ARRIVE Introduction near Chicago?
Quebec
Ontario
Introduction near Chicago?
Aphids on plant material?
Based on an
original map by
Rob Venette,
U.S. Forest Service

7. Unexploited resource Lack of Attention
ARRIVE
SURVIVE
Unexploited resource
- secondary host (soybean) present
- few economic soybean insect pests
in the Midwest
Lack of Attention
‘No-brainer crop’, ‘GM crop’
Plant - RoundUp - Harvest
Didn’t notice initial colonizers

8. Reproductive biology of aphids
SURVIVE
Reproductive biology of aphids
Partheno-
genesis
Born
‘pregnant’
Live
Birth

9. key: Presence of the Primary host SURVIVE Rhamnus cathartica also non
native &
invasive

10. D. Voegtlin (INHS), Quad Cities, Fall 2006

11. SURVIVE
THRIVE
Ontario
Quebec
2004
distribution

12. [Ragsdale lab, Univ. of Minnesota]
THRIVE
High Reproductive
Capacity
[Ragsdale lab, Univ. of Minnesota]
Total #
nymphs 75 73 23
Doubling
time
(days) 2
1.5
---
Temp
68oF
77oF
86oF
95oF

13. Tremendous ability to disperse
THRIVE
Tremendous ability to disperse
Saginaw MI,
August 1st, 2001
Avg 7,000
SBA per plant X
plant population
90% alatoid
Potential for 800 million winged SBA
generated per acre in early August.

14. SBA landing on a
calm morning.
East Lansing, 2005

15. Jays debug the Orioles. Insects take over SkyDome -
Toronto invaded by swarms of aphids.
Clouds of bugs descend on
downtown streets Aug. 3, 2001.
“At least they weren't killer bees.”
Jays debug the Orioles. Insects take over SkyDome -
Toronto crushes Baltimore By John McCauley bluejays.com 8/3/2001

16. Inadequate or poorly-timed
THRIVE
Inadequate or poorly-timed
biocontrol
native &
non-native
predators
can’t keep up
some years
entomo-
pathogens
infect late
lack of
parasitoids

17. THRIVE
Outbreaks: 2001, 2003, 2005, some in 2007

18. Feeding from large #s of Aphids
sucks plant juices
specialized gut removes sugar
amino acid limited
Other problems:
Honey dew
Sooty mold

19. Impact of direct feeding (thousands of SBA per plant)
Early (June) infestation
Mid/late (July/Aug) infestation
Mervyn Erb

20. Other impacts of aphid feeding
nutrients deficiencies (potassium) may increase loss
adequate K K
deficient

21. Local Impact – Yield Loss plant height leaf drop # nodes per plant10 20 30 40 50 60
UNT D 17
(-70%)
Yield, bu/acre
Saginaw County, MI
2005
CRU C
(-40%) +
WAR A B 36
(-30%)
Local Impact –
Yield Loss
plant height
leaf drop
# nodes per plant
# pods per node
# beans per pod
bean quality

22. June July August Landscape Impact – Virus transmission
Avg # of aphids per trap in squash field
(Peaks are made up primarily soybean aphids) 40 80
120
160
June
July
August 25 9 23 6 22 27 2 16 30 13
Western MI, 2003
# SBA
per
trap

23. SBA outbreak years
(’01, ’03, ’05) in Michigan
Bean common mosaic
Cucumber mosaic
Watermelon mosaic
Zucchini yellows
Potato virus Y

24. ---------------------10---------------------
Economic & Social Impact – Increased pesticide use
1999 NASS Survey IL
< 1% 1 IN 0% MI 0% MN 0% OH
<1% 1
% acreage
# of products
(permethrin, chlorpyrifos)
2005 NASS Survey IL 9% OH
18% IN MI
42% MN
30%
(permethrin, chlorpyrifos, dimethoate, esfenvalerate
bifenthrin, cypermethrin, cyhalothrin, cyfluthrin,
methyl parathion, thiamethoxam)
% acreage
# of products

25. Post-detection of SBA Concentrated on insecticides scouting techniques
thresholds
improve application technology
Introduction of soybean rust:
“the best thing that ever happened to soybean aphid”
- increased focus on scouting, spray technology

26. Aphid Suction Trap Network
Aphid
Suction Trap
Network
- annual prediction

27. Medium term: Classical biocontrol
Foreign collection
Climate matching
Quarantine, testing
Field release

28. Susceptible accession
Long term:
Host Plant resistance
Pictures courtesy of
Dr. Duchen Wang
MSU Soybean Breeder
Susceptible accession
Resistant accession

29. Annals of the Entomological Society of America
A source for more information:
Annals of the Entomological Society of America
Vol. 97, No. 2, March 2004
SPECIAL FEATURE ON SOYBEAN APHID
Soybean Aphid Biology in North America
Soybean Aphid in China
Assessing the SBA Invasion
Aphid identification
Suitability of Overwintering Hosts
Population Dynamics in China  
Soybean Aphid Predators
Prospects for Classical Biological Control