Christian-Albrechts-University Kiel
Institute for PhytopathologyDept. Biotechnology & Biol. Control
Biological Control of Diabrotica with EPN
Ralf-Udo [email protected]
www.e-nema.de
Diabrotica in Europe
Salzau, March 27, 2009
Entomopathogenic Nematodes and their
Symbionts
Nematodes Bacteria
Rhabditida Enterobacteriaceae
Closely related to Caenorhabditis elegans
Steiner, G. - in 1923 described Aplectana kraussei from a massive outbreak of the spruce sawfly, Cephaleia abietis in Westfalia, Germany. Krausse, a forest entomologist from Eberswalde, had sent him an infected larva. The description was without many details as he had available only 15 female and 5 male nematodes.
Historical Review into EP Nematology
Entomopathogenic nematodes and their symbiotic bacteria
• Worms of 0.5 - 0.9 mm length• Present in all soil environments • Dauer juveniles (DJ)free-living in
the soil, reproduction only in host insects
• DJ well adapted for long-term survival in the soil (fat reserves, non-feeding, ambushing)
• Symbiotic bacteria in the intestine, symbiosis during nematode growth and development
Life cycle
Dauer juveniles enter the host
The symbiotic bacteriaare released
The insect dies,nematodes developeto adults
Offspring exit from insect cadaver and searching for new hosts
Xenorhabdus and Photorhabdus spp.• Nematode transmits bacterium into sterile environment• Bacteria contribute to kill host insect • Bacteria provide essential nutrients for nematodes• Photorhabdus spp. bioluminescent (not flourescent) • A mutualistic relation: symbiosis
Xenorhabdus is not producing light
Burnell, Maynooth, Ireland
How are EPN are attracted by insects?
• EPN are attracted by CO2 and vibrations• Penetration behaviour is triggered by substances on the insect cuticle• EPN react to plant SOS signals (Rasman et al. 2005, Nature)
?
ß - Caryophyllene
Diabrotica larvae
Christian-Albrechts-University Kiel
Institute for PhytopathologyDept. Biotechnology & Biol. Control
Use of EPN in biocontrolIt´s mainly a matter of application costs
Nema-green (5x109/ha)
Home Gardening Internet – > 2000 €/ha
Golf Market – 800 €/ha
Nemycel (2x106/m² =20x109/ha)
Mushroom Farm + Distrib. – 500-1000 €/ha
Nemapom (1.5x109/ha)
Distributor – 150 €/ha
Control Diabrotica virgifera v. (109/ha)
Product cost must be < 100 €/ha
Nema-green: grub control
Nemycel: sciarid control
Nemapom: cydia control
Instar susceptibility
• All instars and pupae areeffectivelykilled,
• Thus timing of sprays is lessimportant
Kurtz Hiltpold 2008 BioControl
L1 L2 L3 PUPAE
Root volatiles from maize hybrids ?
Interaction
Pest
Host Biocontrol Agent
Nematode orientation in the field
Pactol (-)
Magister (Caryophyllene +)
Rasmann et al., 2005, Nature; Hiltpold 2008 phd thesis.
• Caryophyllene is mainly important for the nematode H. megidis and less for H. bacteriophora,
37
63
49
0
20
40
60
80
100
St. feltiae H. bacteriophora H. megidis
Nematode species, applied in April with sowing
Red
uctio
n D
iabr
otic
a v.
virg
ifera
(% A
bbot
t cor
rect
ed)
Application atsowing (April)
25
59 57
0
20
40
60
80
100
St. feltiae H. bacteriophora H. megidis
Nematode speciey applied as row sprays in June
Redu
ctio
n of
Dia
brot
ica
v. v
irgife
ra(%
Abb
ott c
orre
cted
)
Application in June to L3H. bacteriophora again working best
Christian-Albrechts-University Kiel
Institute for PhytopathologyDept. Biotechnology & Biol. Control
Application methods + time
Diabrotica virgifera v.
5,7 5,9
21,5
8,65,6
22,9
0
5
10
15
20
25
30
35
Fluid rowspray with
sowing
Powder rowspray with
sowing
Flat sprayon soil after
sowing
Fluid rowspray in
June
Fluid flatspray in
June
Control
Applications of H. bacteriophora
% R
oots
with
eco
nom
ic d
amag
e(>
3 in
1 to
6 Io
wa
Sca
le)
75%62%6%74%75%Reduction
IOWA Scale Reduction
0.3
1.0
0.4 0.2 0.2
1.7
0
1
2
3
Fluid rowspray with
sowing
Powder rowspray with
sowing
Flat spray onsoil aftersowing
Fluid rowspray in June
Fluid flatspray in June
Control
Applications of H. bacteriophora
Dia
brot
ica
adul
ts e
mer
ged
/10
0 eg
gs /
plan
t
Christian-Albrechts-University Kiel
Institute for PhytopathologyDept. Biotechnology & Biol. Control
Application method and time
105/m² Heterorhabditis bacteriophoraStefan Toepfer
88%88%57%41%82%Reduction
Reduction Adult Emergence
Step 5 Lowest effective dose
y = 14.4Ln(x) + 72.1r2 = 0.4
0
1020
3040
50
6070
8090
100
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4Million H. bacteriophora per metre
Mea
n ne
mat
ode
effic
acy
(% R
educ
tion
of ro
ot d
amag
e m
easu
red
by 0
.00
- 3.0
0 no
de in
jury
sca
le
com
pare
d to
con
trol)
Step 5 Lowest effective doseNeeded for product price estimation
• The lowest dose that canreach similar efficacies as insectides is 0.1 Million 0.1 Million H.bactH.bact / m/ m
• (=1.3 x 10 9 / ha).
Christian-Albrechts-University Kiel
Institute for PhytopathologyDept. Biotechnology & Biol. Control
Diabrotica v. virgifera
Szatymaz
00,5
11,5
22,5
33,5
44,5
5
Control Force H.b.0.03
H.b.0.1
H.b.0.2
Poncho
Treatment
Adul
t D. v
. virg
ifera
em
erge
d / p
lant
/ 10
0 eg
gs
Toepfer, Kuhlmann, Peters, Ehlers, 2007
Christian-Albrechts-University Kiel
Institute for PhytopathologyDept. Biotechnology & Biol. Control
Diabrotica v. virgifera
Toepfer, Grabenweger, Peters, Ehlers, 2007
1,06
0,500,13
3,25
1,75
7,31
0,00
1,00
2,00
3,00
4,00
5,00
6,00
7,00
8,00
9,00
10,00
11,00
12,00
nicht infiziert UK Poncho EPNspät EPNfrüh Granulat
Christian-Albrechts-University Kiel
Institute for PhytopathologyDept. Biotechnology & Biol. Control
Diabrotica Control
Recommendation: Apply granularformulation of H. bacteriophora withsowing in April/May at 1.3 x 109 ha-1
Application costs at 150 €/ha
Further reduction of costs possible:
- Increasing production capacity
- Lower application density
- Improved application technology
- Prolonged shelf life