Future Management Of PCN In A World With Fewer Pesticides · Future Management Of PCN In A World...

Scottish Agronomy Ltd

Future Management Of PCN In A World With

Fewer PesticidesEric Anderson


Scottish Agronomy LtdProject Collaborative Partners

John M Stevenson Limited, Luffness Mains


SASA James Hutton InstitutePotato Council SoilEssentials LtdSyngenta AgriiLothian Aerial Imaging AgricoMcCain KWSDupont HZPC


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


PCN

PCN

Not PCN

Not PCN


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


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


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.


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


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?


“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.


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


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


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


Is the determinate nature of Innovator important for prevention of 2nd

generation G pallida??


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


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.


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


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

You are doing better than you think, but not as well as you might!

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