Soybean Cyst Nematode: Sources of Resistance

and Nematicides Sam Markell, Ph.D.

Extension Plant Pathologist

Questions to Answer

• Where is SCN? • How do you manage SCN? • How does resistance work?

– What are sources of resistance? • What do we know about nematicide seed

treatments?

Source: www.entm.purdue.edu/nematology/lifecycle.html

Soybean Cyst Life Cycle

Sampling - Egg Counts

McGawley, Louisiana State University

McGawley, Louisiana State University

Source: www.entm.purdue.edu/nematology/lifecycle.html

Soybean Cyst Life Cycle

Egg Counts

Management

Where is SCN?

SCN Survey 2013-2015

• Grower based sampling – Soil sample bags distributed at County offices – Distributed at SCN field days – Cost covered by the ND Soybean Council – Sent to the lab – Maps created by Michael Knudson (G.F. Ext)

• Data reported in egg counts

EFFECT OF SCN ON GROWTH OF DRY BEAN (Courtesy Berlin Nelson)

Pinto bean field experiment in 2007

CONTROL 5,000 EGGS/100 CC SOIL 10,000 EGGS/100 CC SOIL

2013

2013

Low levels may/may not be false positive

SCN is moving north

How do you manage SCN?

• Sample for it • Rotate • Resistance • Seed Treatments (?)

Sampling for SCN

http://www.photo-dictionary.com/phrase/5305/antique-tractor.html

http://www.photo-dictionary.com/phrase/5305/antique-tractor.html

http://www.photo-dictionary.com/phrase/5305/antique-tractor.html

http://www.weather.com/outlook/weather-news/news/articles/midwest-flood-fears_2010-03-05

http://www.grahamowengallery.com/photography/geese.html

Texas dust storm – 1935 http://en.wikipedia.org/wiki/File:Dust_Storm_Texas_1935.jpg

Richland County, ND

Sampling for SCN

Rotation Recommendations

SCN Hosts • Dry Edible Beans • Chickweed • Field Pennycress • Purselane • Shepard’s Purse • Sweet Clover • Wild Mustard

Nelson

40%

Resistance

How does SCN resistance work?

• Female enters the root • Sets up a feeding structure (syncytium)

– Becomes sedentary

Healthy Female

How does SCN resistance work?

• Female enters the root • Sets up a feeding structure (syncytium)

– Becomes sedentary • Resistance acts on the syncytium

– Does not fully form or deteriorates – Juveniles starve

2 days

Original Images - B. Mathews, USDA: Reproduced from Tylka et al. Soybean Cyst Nematode Management Field Guide - 2008

2 days

Original Images - B. Mathews, USDA: Reproduced from Tylka et al. Soybean Cyst Nematode Management Field Guide - 2008

• Source of resistance – Plant Introduction (PI) lines

Where does resistance come from?

Resistance Gene • Single gene • Easy to breed into

varieties • Very effective

Source of Resistance • Line with multiple genes • Hard to incorporate into

varieties • Effectiveness varies

What is a source of resistance?

Not all resistant soybeans are the same same field

Courtesy Tylka, Baum

Lots of Genes

Resistance Gene • Single gene • Easy to breed into

varieties • Very effective • Easy for pathogen to

overcome

Source of Resistance • Line with multiple genes • Hard to incorporate into

varieties • Effectiveness varies • Hard for pathogen to

overcome

What is a source of resistance?

Sources of Resistance

1. PI 54840 2. PI 88788 3. PI 90763 4. PI 437654 5. PI 209332 6. PI 89772 7. PI 548316

Sources of Resistance

1. PI 54840 (Peking) 2. PI 88788 3. PI 90763 4. PI 437654 5. PI 209332 (Hartwig or CystX) 6. PI 89772 7. PI 548316 (Cloud)

Sources of Resistance

1. PI 54840 (Peking) 2. PI 88788 3. PI 90763 4. PI 437654 5. PI 209332 (Hartwig or CystX) 6. PI 89772 7. PI 548316 (Cloud)

Number of SCN resistant varieties in Iowa (Tylka)

0100200300400500600700800900

PI 88788

Other

Courtesy: Tylka

SCN Resistance • Two sources

• Critical to rotate – Varieties – Sources (if possible)

Seed Treatments

Seed Treatments for Nematodes

• Early Season Protection (primarily) • Limit the first ‘cycle’ of nematode infection

Seed Treatments

• Avicta Complete – Active Ingredient – Abamectin – Inhibits the central nervous system – Moves on surface of roots

Seed Treatments

• Clariva Complete – Active Ingredient –Pasteuria nishizawae – Obligate parasite of SCN

Seed Treatments

• N-Hibit – Active Ingredient – Harpin protein – Natural product of a bacteria (E. amylovora) – Stimulates natural defenses – only

nematodes entering roots

Seed Treatments

• Poncho VOTiVO – Active Ingredient – Bacteria (Bacillus firmus) – Repellent, barrier or induced resistance – Does kill the nematodes

56

© 2014 Regents of the University of Minnesota. All rights reserved.

56 56

2014 Statewide trials on Clariva Complete Funded by MSR&PC

Seed and treatments supplied by Syngenta Crop Protection

BRUCE POTTER (507) 276-1184

BPOTTER@UMN.EDU HTTP://SWROC.CFANS.UMN.EDU

57

© 2014 Regents of the University of Minnesota. All rights reserved.

2014 STATEWIDE CLARIVA Seed Treatment: breakdown of treatments by active ingredient

Nematicide Insecticide ----------------------- Fungicide -----------------------

Untreated ---- ---- ---- ---- ----

Clariva Complete

P. nishizawae (Clariva©)

thiamethoxam (Cruiser©)

mefenoxam (Apron©)

fludioxomil (Maxim©)

sedaxane (Vibrance©)

CruiserMaxx + Vibrance ---- thiamethoxam

(Cruiser©) mefenoxam

(Apron©) fludioxomil

(Maxim©) sedaxane (Vibrance©)

58

© 2014 Regents of the University of Minnesota. All rights reserved.

2014 STATEWIDE CLARIVA -TREATMENTS

TRT # SCN VAR SEED TREATMENTSouthern

1 SCN resist NK S22-S1 Untreated2 SCN resist NK S22-S1 Clariva Complete3 SCN resist NK S22-S1 CruiserMaxx +Vibrance4 SCN susc NK S22-F8 Untreated5 SCN susc NK S22-F8 Clariva Complete6 SCN susc NK S22-F8 CruiserMaxx +Vibrance

Northern1 SCN resist NK S06-H5 Untreated2 SCN resist NK S06-H5 Clariva Complete3 SCN resist NK S06-H5 CruiserMaxx +Vibrance4 SCN susc NK S06-R9 Untreated5 SCN susc NK S06-R9 Clariva Complete6 SCN susc NK S06-R9 CruiserMaxx +Vibrance

Res

Res

Susc

Susc

59

© 2014 Regents of the University of Minnesota. All rights reserved.

2014 STATEWIDE CLARIVA SEED TREATMENT, SCN RESISTANCE AND MATURITY EFFECT ON YIELD - PRELIMINARY

50.00

60.00

70.00

80.00

90.00

100.00

110.00

120.00

% O

F M

EAN

SIT

E Y

IELD

SEED TRT. X SCN RESIST. X MATURITY GROUP

NONE Susc (North)

CLARIVA Susc

FUNG Susc

NONE Res

CLARIVA Res

FUNG Res

NONE Susc( South)

CLARIVA Susc

FUNG Susc

NONE Res

CLARIVA Res

FUNG Res

Northern Southern

Means and standard errors

Res

Res

60

© 2014 Regents of the University of Minnesota. All rights reserved.

2014 STATEWIDE CLARIVA SEED TREATMENT, SCN RESISTANCE AND MATURITY EFFECT ON YIELD - PRELIMINARY

50.00

60.00

70.00

80.00

90.00

100.00

110.00

120.00

% O

F M

EAN

SIT

E Y

IELD

SEED TRT. X SCN RESIST. X MATURITY GROUP

NONE Susc (North)

CLARIVA Susc

FUNG Susc

NONE Res

CLARIVA Res

FUNG Res

NONE Susc( South)

CLARIVA Susc

FUNG Susc

NONE Res

CLARIVA Res

FUNG Res

Northern Southern

Means and standard errors

SCN Seed Treatments

• Not a substitute for resistance • Likely some effect • Hard to measure • May be best applied in targeted area

Thank You!

Questions?

Acknowledgements Michael Knudson, Grand Forks County Phil Glogoza and Bruce Potter, U of MN

Greg Tylka, Iowa St. U. Berlin Nelson, NDSU

What is an Hg-Type?

What is an Hg-Type?

• It’s like a ‘race’ or a ‘strain’ • It tells you if a nematode can reproduce on

a source of resistance

SCN Type Indicator Lines

1. PI 54840 (Peking) 2. PI 88788 3. PI 90763 4. PI 437654 5. PI 209332 (Hartwig or CystX) 6. PI 89772 7. PI 548316 (Cloud)

Susceptible Check = Lee74

Courtesy: Berlin Nelson

• Count! • Number on Lee 74 is set to ‘100’ • If > 10% reproduction on any PI line, it is

considered susceptible • The susceptible PI lines become the Hg-

type name

What is Hg Type?

0102030405060708090

100

Lee 74 Peking PI88788

PI90763

PI437654

PI209332

PI89772

PI548316

Fem

ale

Inde

x

Indicator Lines Line Number 1 2 3 4 5 6 7

Susc Check

Hg Type 0

What is Hg Type?

0102030405060708090

100

Lee 74 Peking PI88788

PI90763

PI437654

PI209332

PI89772

PI548316

Fem

ale

Inde

x

Indicator Lines Susc Check

Hg Type 2

Line Number 1 2 3 4 5 6 7

What is Hg Type?

0102030405060708090

100

Lee 74 Peking PI88788

PI90763

PI437654

PI209332

PI89772

PI548316

Fem

ale

Inde

x

Indicator Lines Susc Check

Hg Type 2.5.7

Line Number 1 2 3 4 5 6 7

What is Hg Type?

0102030405060708090

100

Lee 74 Peking PI88788

PI90763

PI437654

PI209332

PI89772

PI548316

Fem

ale

Inde

x

Indicator Lines Susc Check

Hg Type 2

Line Number 1 2 3 4 5 6 7

What is Hg Type?

0102030405060708090

100

Lee 74 Peking PI88788

PI90763

PI437654

PI209332

PI89772

PI548316

Fem

ale

Inde

x

Indicator Lines Susc Check

Hg Type 2

Line Number 1 2 3 4 5 6 7

How common is Hg-Type 2+

Between 2006 and 2008 • Tennessee (94 populations) = 93% • Illinois (32) = 88% • Indiana (259) = 56% • Ontario (132) = 27% • North Dakota (?) = ?

Faghihi et al., Plant Health Progress 2010