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Scottish Agronomy Ltd
Future Management Of PCN In A World With
Fewer PesticidesEric Anderson
Scottish Agronomy Ltd
Scottish Agronomy LtdProject Collaborative Partners
John M Stevenson Limited, Luffness Mains
Scottish Agronomy Ltd
SASA James Hutton InstitutePotato Council SoilEssentials LtdSyngenta AgriiLothian Aerial Imaging AgricoMcCain KWSDupont HZPC
Scottish Agronomy Ltd
SASA Lab – Old & New PCN Diagnostics
Visual examination
15-20 samples/day
3 years to train
Automated PCR
Up to 400 samples/day
3 weeks to train
Scottish Agronomy Ltd
PCN
PCN
Not PCN
Not PCN
Scottish Agronomy Ltd
Scottish Agronomy Ltd
Diagnostic & Viability Criterion
Scottish Agronomy LtdLuffness Trial3 options chosen for assessing PCN levels• Egg counts using cysts extracted from the float
(very expensive) – Part A• PCR CT values based on statutory SASA soil tests
within the float from the Carousel (cheap) – Part B• PCR CT values based on statutory SASA method
but using cysts extracted from the float (moderately expensive) – Part C
• 400 ml samples for each of the above assessments
Scottish Agronomy Ltd
Pre-planting Results: PCN Cyst counts
Part A Cyst Counts Cysts/g Part C Cyst Counts Cysts/g
TR UT TR UT TR UT TR UT
0.2 0.1 0.5 0.2 0.2 0.2 0.5 0.2
0.2 0.2 0.2 0.2 0.2 0.2 0.3 0.3
0.2 0.1 0.4 0.2 0.2 0.1 0.4 0.3
0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
0.2 0.1 0.2 0.1 0.2 0.1 0.2 0.2
0.2 0.1 0.3 0.1 0.2 0.1 0.3 0.1
0.2 0.2 0.5 0.3 0.2 0.2 0.4 0.3
0.5 0.4 0.2 0.2 0.5 0.3 0.2 0.1
0.5 0.3 0.1 0.2 0.5 0.3 0.1 0.2
0.5 0.3 0.1 0.2 0.6 0.4 0.2 0.3
0.6 0.4 0.1 0.1 0.5 0.4 0.1 0.1
0.6 0.3 0.1 0.2 0.5 0.4 0.1 0.2
0.7 0.4 0.2 0.2 0.5 0.4 0.1 0.2
0.4 0.2 0.1 0.1 0.4 0.3 0.1 0.1
8 Beds 8 Beds
Conclusions: The samples were very well mixed Cyst counts ranged from 64 to 400
cysts per sample
Scottish Agronomy Ltd
Commercially Available G pallida Resistant Varieties in Trial
• Osprey – Bakers• Royal - French fry• Performer * – Chipping and baking• Arsenal – Crisping• Innovator * – Processing (TRV/spraing
susceptible) • Eurostar * - French fry and ware markets
Scottish Agronomy LtdLuffnessUntreated 2014
Variety PiCysts
/500g soil
Pi Eggs &
Juv/g soil
PCR CT value
B samplePi
PCR CT value
B samplePf
Change Pa2/3Resistance
Maris Piper
100 2.01 27.6 24.9 -2.6 2
Osprey 110 3.96 26.9 25.4 -1.5 3Royal 115 5.24 28.8 28.5 -0.4 4Arsenal 125 5.06 25.5 32.8 7.3 8Eurostar 85 1.60 27.4 32.7 5.3 R?Innovator 90 4.46 28.8 34.5 5.7 9Performer 115 3.81 27.6 34.2 6.5 R?
Scottish Agronomy LtdTolerance• Tolerance is defined as the yield response of a
potato crop under attack from nematodes in relation to a nematode free crop.– Do not observe a clear association between tolerance and
yield potential in the absence of potato cyst nematodes or in the level of resistance to them.
• Second stage juveniles hatch from cysts when they detect that potatoes are being grown, migrate to the roots and upon finding a suitable root, will invade.
• This invasion causes damage to the plant which may subsequently lead to a reduction in the yield (capabilities) of the plant.
Scottish Agronomy Ltd
Effect of Nematicide on % Increase In Total Yield
Holbeach - R264 John Keer: GrowScience 2007
G. pallida population of 20-22eggs/g soil and was un-irrigated fine sandy silt loam
Scottish Agronomy Ltd
Percentage Area of Potato Production with Resistance
GB England ScotlandRo1 52.25 % 54.16 % 40.21 %Pa2/3 (2) 1.10 % 0.70 %Pa 2/3 (3) 1.35 % 6.25 %Pa2/3 (4) 4.96 % 6.06 %Pa2/3 (8-9) 3.39 % 1.20 %Pa 2/3 (2-9) 10.42 % 10.79 % 14.21 %
Scottish Agronomy LtdG. pallidaResistance
• The genetic diversity of UK G. pallida field populations, compared to those of G. rostochiensisposes challenges for deploying resistance that is both durable and effective.– G. pallida is exceptionally heterogeneous– Durable resistance is polygenic making it difficult to
breed from.
• Currently monogenic resistance to G. pallida has been identified : the H2 locus from Solanummultidissectum and Gpa2 gene derived from S. tuberosumssp. andigena
Scottish Agronomy LtdSpread of Globoderarostochienisis and G. pallida
• Is there any geographical pattern in genetic variability of G pallida in Europe?
• Has this lead to regional changes in in virulence that will result in subtle changes in the effectiveness of resistant potato varieties?
Scottish Agronomy Ltd
“PA3 Old” Luffness from field 1
Luffness Field 1, 2009
Harper Adams, 2011 Jersey, 2011
“PA3 Old” Lindley
Pathotype Pa1 Populations Differ From Pa2/3 Populations in their Virulence on
Hosts with the H2 Resistance Gene and in their Isozyme Profiles
Source: V Blok, James Hutton Institute
Luffness, Lindley & Duddingston
Scottish Agronomy LtdLuffnessUntreated vs Treated
Scottish Agronomy LtdPasteuria spp
• Pasteuria penetrans has much potential as a biological control agent and a commercial product (Nematech Ltd., Tokyo) has been produced for control of root-knot nematodes.
• The spores of P. penetrans are extremely robust and have a long shelf life (several years).
• However, mass production remains difficult and individual isolates of the bacterium have restricted host ranges that may limit commercial development.
Scottish Agronomy Ltd
Number of eggs/g soil over the growing season at Luffness in
2011 over the 20 week growing period Source: Agata Kaczmarek PhD Thesis 2014
Scottish Agronomy Ltd
G. rostochiensis and G. pallidaat Different Temperatures
Source: Agata Kaczmarek PhD Thesis 2014
males
males
~9‐10 weeks at 14ºC
~8‐9 weeks at 17ºC
G. rostochiensis
G. pallida
Scottish Agronomy Ltd
0
5
10
15
20
25
0 20 40 60 80 100 120 140 160
21 weeks
Lincolnshire: 4 April – 5 September
Tempe
rature ºC
Average
15.3
Tempe
rature ºC
20
15
10
Luffness: 11 April – 3 September
Soil Temperatures - 2014
20 weeks
Scottish Agronomy Ltd
Is the determinate nature of Innovator important for prevention of 2nd
generation G pallida??
Scottish Agronomy Ltd
Biological Control
Nematophagousfungi Pochoniachlamydosporia
Solanum sisymbriifoliumSticky Night Shade
Caliente 99 Mustard
Scottish Agronomy LtdSolanum sisymbriifoliumSticky Night Shade
• Advantages– Fully resistant to PCN– Triggers hatch, more J2 per g root than s tuberosum
observed. May be due to finer root hairs. The two solanum species exude different hatching factors but send common signal to PCN.
– Easy to destroy– Resistant to selected herbicides, so chemical weed
control is possible– Frost tolerant– Blight resistant– Can reduce PCN by more than 75%
Scottish Agronomy LtdSolanum sisymbriifoliumSticky Night Shade
• Disadvantages– Cost £550/ha incl seed, fert, herb and cultivation.– Slow to establish– Prefers low pH– Reduced growth in sandy loams– May require irrigation to establish– Requires fertiliser application and weed control– High thermal activity threshold of seed lines
currently available
Scottish Agronomy Ltd
Integrated ControlIntegration of biological control agents with
other management strategies
• None of the bcas of PCN have provided > 80% control; most reductions in populations have been considerably lower and more variable!
• Methods to reduce nematode populations:– Crop rotation with resistant hosts.– Combined use with nematicides.– Application of bcas after partial soil sterilisation
• Methods to increase microbial activity:– Soil amendments and green manure crops.
• The use of integrated strategies, requires the production of reliable data to demonstrate field efficacy.
Scottish Agronomy Ltd
2-Phenylethyl ITC levelsFiona Taylor et al 2014
• Compared to allyl and benzyl –levels of 2-phenylethyl much lower• Highest –B. Juncea cv. Caliente mustard 99
– Stage 1 (28 mg/L) stage 3 (31 mg/L)
• Similar trend B. Napus Forage Rape cv. Hobson
Scottish Agronomy Ltd
Field Screening of Biofumigant Species For The
Reduction of PCN Source: Watts et al 2014
• Several studies have confirmed that PCN mortality is increased after exposure to ITC’s with the derivatives 2-propenyl-isothiocyanate and 2 –phenylethyl-isothiocyanate being suggested to be particularily nematicidal.
• Biofumigation was shown to reduce encysted egg viability by approximately 42%– In the study conducted by Ngala et al. (2014), incidence of
G. pallida was reduced by approximately 50% in summer sown crops, however, biofumigation effectiveness was markedly reduced in overwintered crops.
Scottish Agronomy LtdWake Up & Smell The Coffee Source: Album cover The cranberries 2001
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