Raquel Campos-Herrera
1, Geoffrey Jaffuel
1, Xavier Chiriboga
1, Rubén Blanco-Pérez
1, Marie Fesselet
2, Vladimir P ů ža
3, Fabio Mascher
2, & Ted C.J. Turlings
11
FARCE Laboratory, University of Neuchâtel, (Switzerland);
2DEFR, Agroscope, Institut des Sciences en Production Végétale IPV, Nyon (Switzerland);
3Laboratory of Entomopathogenic Nematodes, Institute of Entomology, Biology Centre, Czech Academy of Sciences, Č eské Bud ě jovice (Czech Republic)
MEASURING ENTOMOPATHOGENIC NEMATODE SOIL FOOD WEBS IN SWISS TILLAGE AGROECOSYSTEM FOR DEVELOPING ROOT-HERBIVORES SUSTAINABLE BIOCONTROL
The natural occurrence of EPN in Swiss agricultural soils is very low, independent of management practices
Augmentation may be a promising strategy to improve the control of root pests of crops under tillage management
Entomopathogenic nematodes
Our objective was to evaluate how below ground multitrophic interactions affect EPN activity and occurrence in agroecosystem with different tillage management. We employed traditional and new molecular methods for the evaluation of samples from two 30-year running Swiss field trials (P20 and P29), located in the Agroscope Institut des Sciences en Production Végétale IPV, (Nyon, Switzerland) Entomopathogenic nematodes
(EPNs) are considered among the most promising biological control agents to protect annual and perennial crops (Georgis et al., 2006)
MULTITROPHIC-INTERACTION
Stuart et al. (2006), Campos-Herrera et al. (2012) Root
Herbivore
Nematophagous fungi
Acari and Collembolla Entomopathogenic
nematodes Beneficial Bacteria
and Fungi
Free-living
nematodes Mutualistic
bacteria
P20 Sampling: April and October 2013 P29
Monoculture (M) /Crop rotation (C) Tillage (T) /no-Tillage (NT) N = 16 (4 each treatment)
Clay soil (CA) / Silty soil (CL) 4 Levels Tillage: T, W15, W8, SD N = 28 (4/3 each treatment)
PRIMERS AND PROBES FOR SWISS SOILS
• 7 new primers/probe for EPN; using 6 published sets
• 6 primers/probe for nematophagous fungi
• 1 primers/probe for Free-living nematodes
* * *
no. IJsdetectedbyqPCR
0 3 6 9 12 15 18
3 IJS 10 IJS
Sf Sca Sg Sbic Sint-g Saff
Swei Sk Ssilv Hz Hb Hm
1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00
Sf Sca Sk-s Saff Hb Hm
no. IJs /100 g dry soil
0.0 0.2 0.4 0.6 0.8 1.0
Plil Cat Hrhos Ao
0 0.01 0.02 0.03 0.04 0.05
IR proportion/100 g dry soilpg DNA/ 100 g dry soil
April October April October
P20 P29
A Entomopathogenic nematodes
B Nematophagous fungi
C Free-living nematodes, Acrobeloides-group
0 1 2 3 4
Monoculture Crop Rotation
0 0.01 0.02 0.03 0.04 0.05
Monoculture Crop Rotation
*
**
0 0.2 0.4 0.6 0.8
CA CL
0 0.004 0.008 0.012 0.016
CA CL
***
***
NF richnesspg DNA/100 g dry soil NF total IRpg DNA/100 g dry soil
Nematophagous fungi
Free-living nematodes, Acrobeloides-group
Minimum quantities and competition with other organisms might reduce the EPN overall activity
Campos-Herrera et al. (2012). J. Nematol., 44, 162-176 Georgis et al. (2006). Biol. Control 38, 103-123 Stuart et al. (2006). Biol. Control, 38, 80-102
HYPOTHESIS
Entomopathogenic nematodes Native populations
LOW ACTIVITY AND OCCURRENCE
1
Root Herbivore
LIMITED AVAILABILITY OF INSECT HOST
2
EXPOSURE TO DISFAVOURABLE ENVIRONMENTAL CONDITIONS
Soil management
3
IN TILLAGE SOILS…
Nematophagous fungi Free-living nematodes Members of the EPN soil food
web will be affected
NEGATIVE AFFECTED, FOLLOWING SPATIAL ASSOCIATION WITH EPN
