promoting sustainable biological control of the soybean aphid: biodiversity and releases of...
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PROMOTING SUSTAINABLE BIOLOGICAL CONTROL OF THE SOYBEAN APHID: BIODIVERSITY AND RELEASES OF PARASITOID WASPS
George Heimpel, LNC13-353
University of Minnesota Dept. of Entomology NCR-SARE’s Farmers Forum,
2015
Arrival and Spread of the Soybean Aphid
Year
1992 1994 1996 1998 2000 2002 2004 2006
Mill
ions
of
acre
s o
r po
und
s sp
raye
d
0
2
4
6
8
10
AcresPounds
No
da
ta (
20
03
)
Invasion of soybean aphid
Insecticide use in North Central States
Source: NationalAg. Statistics Serv.
Supply of natural enemies in the landscape
Generalist predators provide biological control of soybean aphid
Biological Control
<
Day 7 Day 140
200
400
600
800
1000
1200
ExclusionOpen
ab
A
B
Soyb
ean
aphi
d pe
r pla
nt +
/- S
EM
How can we improve upon this level of biological control?
• 1. Taking advantage of biodiversity
• 2. Releasing parasitoid wasps
Winter-Planted Rye Cover- Cropped with Organic Soybean
Autumn: Harvest corn
Autumn: Plant rye
Spring: Plant soybean
Summer: Mow rye
Autumn: Harvest soybean
P. Porter
P. Porter
Soybean drilled into ryeLee Thomas June 12, ‘03
P. Porter
P. Porter
Z. Sezen
Results: Austin (Organic Farm)
Date
6/1/06 7/1/06 8/1/06 9/1/06
SB
A p
er p
lan
t
0
200
400
600
800
1000
1200With Rye (a)Without Rye (b)
Treatment
With Rye Without RyeY
ield
(B
u/A
cre)
0
10
20
30
40
Results: Lamberton Exp. Station
Date
6/1/06 7/1/06 8/1/06 9/1/06
SB
A p
er p
lan
t
0
50
100
150
200
250With Rye (a)Without Rye (a)
Treatment
With Rye Without Rye
Yie
ld (
Bu
/Acr
e)
0
10
20
30
40
Date
6/1/06 7/1/06 8/1/06 9/1/06
SB
A p
er p
lan
t
0
2000
4000
6000With Rye (a)Without Rye (b)
Results: Felton (Organic Farm)
Treatment
With Rye Without Rye
Yie
ld (
Bu
/Acr
e)0
5
10
15
20
25
30
35
Results: Rosemount Exp. Station
Date
6/1/06 7/1/06 8/1/06 9/1/06
SB
A p
er p
lan
t
0
20
40
60
80
100
120
140With Rye (a)Without Rye (b)
Treatment
With Rye Without Rye
Yie
ld (
Bu
/Acr
e)
0
10
20
30
40
Z. Sezen
Why fewer aphids in the presence of rye?
- Little evidence for better biological control.
- Likely less aphid colonization or lower aphid growth rates.
The role of Asian parasitoids• Aphelinus certus - established• Aphelinus glycinis – being introduced
Aphid parasitoid life cycle
Aphelinus certus
Dots: sampling locations (Minn Dept. of Ag.)
Blue: counties with Aphelinus certus
Aphelinus certus
2012 2013 2014
In Rosemount, MN
Aphelinus glycinis• 2013 releases• 2014 releases• Overwintering study
Date (2014)
July 26 Aug 12 Aug 27
Ap
helin
us
mu
mm
ies per p
lant 0
10
20
30
40Northfield Cottonwood
75,000 A. glycinisreleased at each
site
Aphelinus glycinis• Overwintering study
Conclusions• Soybean aphid is a pest despite natural biological control• We are trying to improve this control by:
• Increasing landscape diversity• Releasing Asian parasitoid wasps.
• Next Steps: Combine these strategies
Acknowledgements• Rye Cover Cropping Work
• Paul Porter, Bob Koch, Lee Thomas,
Paul Guiney
• Aphelinus certus• Joe Kaser, Keith Hopper
• Aphelinus glycinis• Nick Padowski, Keith Hopper
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