NACAA AM/PIC 2007
Invasive Species:
Arrive, Survive, and Thrive
‘Tiny Terrors’…
The Soybean Aphid
Chris DiFonzo
Field Crops Entomology
Michigan State University
the Soybean Aphid, Aphis glycines Matsumura
Secondary host:
Glycine max
(soybean)
fundatrix
June
March
eggs
July
Winter
August
Sept
Fall
males
Primary host:
Rhamnus spp.
(buckthorn)
oviparae
gynoparae
General Invasion Process
Arrive
Survive
Thrive
ARRIVE
Siberia
Japan
China
Philippines
Thailand
Malaysia
Indonesia
Australia
1999
U.S. 2000
ARRIE
Trade and Tourists
- direct flights from Asia
to Detroit, Chicago, Minneapolis
- increase in goods imported from Asia
ARRIVE
Quebec
Ontario
Based on an
original map by
Rob Venette,
U.S. Forest Service
Introduction near Chicago?
Aphids on plant material?
2000
Discovery
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
SURVIVE
Reproductive biology of aphids
Parthenogenesis
Born
‘pregnant’
Live
Birth
SURVIVE
key:
Presence
of the
Primary
host
Rhamnus
cathartica
- also non
native &
invasive
D. Voegtlin (INHS), Quad Cities, Fall 2006
SURVIVE
Ontario
THRIVE
Quebec
2004
distribution
THRIVE
High Reproductive
Capacity
[Ragsdale lab, Univ. of Minnesota]
Temp
68oF
Total
#
nymphs
75
Doubling
time
(days)
2
77oF
73
1.5
86oF
23
2
95oF
0
---
THRIVE
Tremendous ability to disperse
Saginaw MI,
August 1st, 2001
Avg 7,000
SBA per plant
X
plant population
X
90% alatoid
Potential for 800 million winged SBA
generated per acre in early August.
SBA landing on a
calm morning.
East Lansing, 2005
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
Inadequate or poorly-timed
biocontrol
lack of
parasitoids
native &
non-native
predators
can’t keep up
some years
THRIVE
entomopathogens
infect late
Outbreaks: 2001, 2003, 2005, some in 2007
THRIVE
Feeding from large #s of Aphids
- sucks plant juices
- specialized gut removes sugar
- amino acid limited
Honey dew
Other problems:
Sooty mold
Impact of direct feeding (thousands of SBA per plant)
Early (June) infestation
Mid/late (July/Aug) infestation
8-29-05
Mervyn Erb
Other impacts of aphid feeding
- nutrients deficiencies (potassium) may increase loss
adequate
K
K
deficient
60
50
Local Impact –
Yield Loss
40
- plant height
- leaf drop
- # nodes per plant
- # pods per node
- # beans per pod
- bean quality
20
Yield, bu/acre
Saginaw County, MI
2005
30
10
0
D
A
50
B
36
C
30
(-30%)
CRU
WAR
(-40%)
17
(-70%)
UNT
CRU
+
WAR
Landscape Impact – Virus transmission
Avg # of aphids per trap in squash field
(Peaks are made up primarily soybean aphids)
160
Western MI, 2003
120
# SBA
per 80
trap
40
0
25
June
2
9
16
July
23
30
6
13
22
August
27
SBA outbreak years
(’01, ’03, ’05) in Michigan
Bean common mosaic
Cucumber mosaic
Watermelon mosaic
Zucchini yellows
Potato virus Y
Economic & Social Impact – Increased pesticide use
% acreage
IL
< 1%
IN
0%
MI
0%
MN
0%
OH
<1%
# of products
1
0
0
0
1
1999 NASS Survey
(permethrin, chlorpyrifos)
2005 NASS Survey
% acreage
# of products
IL
9%
IN
18%
MI
42%
MN
30%
OH
18%
---------------------10--------------------(permethrin, chlorpyrifos, dimethoate, esfenvalerate
bifenthrin, cypermethrin, cyhalothrin, cyfluthrin,
methyl parathion, thiamethoxam)
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
http://www.ncipmc.org/traps/
Aphid
Suction Trap
Network
- annual prediction
Medium term: Classical biocontrol
Climate matching
Quarantine, testing
Foreign collection
Field release
Long term:
Host Plant resistance
Pictures courtesy of
Dr. Duchen Wang
MSU Soybean Breeder
Susceptible accession
Resistant accession
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