Potato Early Dying Presentation

Potato Early Dying

Soil Ecology University of Manitoba Mario Tenuta Department of Soil Science @soilecologyUMan

Presentation to PEI Potato Growers February 2 & 3, 2018 Potato Early Dying

• Essentially: the fungus,Verticillium – Two species,V. dahliae, V. albo-atrum – Either fungal pathogen alone, – or in conjunction with root lesion nematode, – Pratylenchus penetrans • Vascular Wilt Disease • Early death • Collethotricum (black dot)? • Erwinia (soft rot)? • Robs yield of large tubers Vascular Symptoms PED Symptoms

PED Symptoms FACTS about Potato Early Dying

Importance Among top potato diseases Concern after mid-70s in many regions Manitoba concern starting late 80s Varies from year-year

Occurs often in patches Sandy spots Wet areas Machinery entrance points Culprits Verticillium dahliae

Not present in Prairie Canada but in ON, PQ, Atlantic Canada

Root Lesion Nematode Pratylenchus penetrans Verticillium dahliae Life-cycle Plant’s responses

Stem section Vascular discoloration

 WILT How does Verticillium survive?

In the soil: Microsclerotia = resting structures

In plant tissues: Mycelium and/or microsclerotia in tubers, leaves, stems…etc Verticillium Host Range

Wide host range Almost all dicotyledon families are susceptible Examples: Alfalfa, Clover, Sunflower, Cabbage, Celery, Cucumber, Pepper, Radish, Rhubarb, Tomato

Any Immune or Resistant plants?: Cereals (all moncots): immune (?) Asparagus, lettuce: moderately resistant

100 A Relation old plating

y = -0.0005x2 + 0.5191x - 18.366

80 R² = 0.608 ofsoil)

P =0.04 1 - method to new

DNA DNA (pgg DNA method 40

20 V. V. dahliae

0 0 50 Verticillium100 inoculum 150(CFU g-1) 200 250

120 B y = 0.002x2 + 0.007x + 0.777 R² = 0.99

soil) 100

1 P =0.0001 - 80

Relationship between Verticillium inoculum level (CFU) in 60 DNA DNA (pgg soils naturally infested with V. dahliae and amount of V. 40 dahliae DNA in soil. (B). Relationship between the number

of V dahliae (Vd1396-9) microsclerotia per gram (mpg) of V. dahliae 20 spiked soil and the estimated concentration of V. dahliae DNA. 0 0 50 100 150 200 250 300 Molina et al. in prep Microsclerotia g-1 soil (mpg) Old Colony Count Method to New PCR Method for V. dahliae in soil Colony Counts vs V. dahliae Copy Number 700000 y = 2154.2x + 1484.6

600000 R² = 0.6507

500000

400000

300000 Copy #/g soil) #/g Copy

200000

100000

0 0 50 100 150 200 250 Colony Counts (# cfu/g) Field A Field B

Counts Old plating method can trick you into dealing with Vert DNA

(A) Inoculum density of Verticillium spp as CFU g-1 soil. (B) Inoculum density of V. dahliae and V. tricorpus as pg DNA g-1 soil. (C) Area under the wilt progress curve (AUWPC) in 2 Disease experimental sites planted to Russet Burbank in Manitoba. Means within a site followed by the same letter are not significant different according to Bonferroni’s multiple comparison test (P>0.05). Error bars are +1 standard error.

Molina et al. in prep A Again more

being fooled Counts Actual relations to Disease in B V. dahliae DNA

field y = 0.39 (V. dahliae DNA) - 0.003 (V. dahliae DNA)2 + 22.46 R² = 0.823 P= 0.002 Relationships between AUWPC and: (A) V. dahliae DNA in soil (pg g-1 soil), (B) V. tricorpus in soil as pg DNA g-1, and (C) Verticillium propagule density as CFU g-1 soil.

C V. tricorpus DNA

y = -6.55 (V. tricorpus DNA) + 0.56 (V. tricorpus DNA)2 +37.54 R² = 0.746 P= 0.0082 Molina et al. in prep Confirming V. tricorpus is not Pathogenic to Poato

Control V. tricorpus V. dahliae

Molina et al. in prep Nematodes

Several plant-parasitic nematodes involved in PED Root lesion nematode (Pratylenchus) P. penetrans*** P. neglectus P. crenatus** Root knot nematode (Meloidogyne) M. hapla

Other Pratylenchus species likely present

Host Range of the Nematode

Wide host range Grasses and cereals, field and vegetable crops, weeds Nonhosts canola, forage pearl millet, Sudan grass, broccoli, onion Preferred hosts corn, carrot, sugar beet, vetch, raspberry, strawberry Naturally occurring in grasslands and pasture

Root lesion Nematode Root Lesion Nematode

D. Wixted Root Lesion Nematode Life Cycle Can be present in Soil Roots Tubers How is the Nematode Involved?

Feeding on root promotes Verticillium to enter roots

Aggravating Verticillium wilt Action threshold - V. dahliae alone V. dahliae : > 12 colonies / g soil Action threshold - V. dahliae & P. penetrans V. dahliae : > 6 colonies / g soil

Nematode alone can cause disease (not Verticillium wilt) 400 – 3000 P. penetrans / kg soil Yield reduction 10 – 43%

So What About Potato Early Dying?

Yield loss Moderate 10-15%, severe 35-60% Late season loss of 5.5-8.6 cwt/ac/day Effect of vigour loss?

Quality loss Tuber discolouration, reduce specific gravityDr. A. Pavlista, U Nebraska Lincoln 20 20 < 3 ounce 3-4 ounce

)

-1 15 -1 15

10 10

5 5

Yield (t ha (t Yield

0 0 0 20 40 60 80 100 0 20 40 60 80 100

20 20

) 4-6 ounce ) Yield of

-1 15 -1 15

10 10 Large

5 5

Yield (t ha (t Yield Yield (t ha (t Yield 6-10 ounce Tubers Robbed 0 0 0 20 40 60 80 100 0 20 40 60 80 100

20 20

) 10-11 ounce >11 ounce

)

-1

15 -1 15

10 10

Yield (t ha (t Yield 5 5

Yield (t ha (t Yield

0 0 0 20 40 60 80 100 0 20 40 60 80 100 % PED disease incdence % PED disease incdence Tenuta et al. Disease and Loss of Total Yield

390

370 r=-0.82

p<0.001

)

1 350 - 330 310 290

Yield (cwt.acre Yield 270 250 0 10 20 30 40 50 60 70 80 90 100 % Disease Incidence Molina et al. Verticillium Soil Test After Harvest and Disease

100 90 80 70 r=0.72 60 p<0.007 50 40 30

20 % Incidence% 10 0 0 5 10 15 20 25 30 35 40 No. of propagules . g-1 of soil Verticillium Wilt and Soil Organic Matter

data from 23 commercial potato fields across Manitoba Manitoba Yield Variability Study

Soil Measure with > 10% Good Areas Relative to Response Between Good Bad Yielding Areas (%) and Bad Yield Areas Verticillium soil 65 Nematodes 134 SOM 88 Electrical Conductivity 146

> 100% means soil measure increased in the Low Yielding Areas Field Variation in Disease and Soil Properties

N/Vert/EC

Organic Matter Control Options

Sudan Grass Trap Crop - Idaho

Need three years to be effective

Phytopathology 86:444-453, 1966. Fumigation

• Liquids that vapourize and generally indiscriminately toxic to soil organisms • Metam Sodium (Sodium N-methyldithiocarbamate) • Chloropicrin (trichloro(nitro)methane) • Telone II (1,3-Dichloropropene) • Formaldehyde • Commonly used in potato production areas

Our First Trial Vapam 2007

70 Control 60

50 40

30 Survival (%) Survival 20 10 Vapam 0 3 7 21 Days after application First Trial With Vapam Killing of Verticillium Already in Soil

No. Verticillium per gram of soil Treatment Before application After application

No application 25 ± 5.81 38 ± 7.57

Vapam 24 ± 6.11 15 ± 9.40 Background - Green manure

Improving soil conditions Direct toxicity

Trap crops Green Manure and Amendment Studies

 Miami Trial (commercial field) – 3 green manures – cv. Mozart (table)

 Shilo Trial (commercial field) – 3 green manures – Vapam trial – cv. Russet Burbank – Mustard seed meal trial

 Canada Manitoba Crop Diversification Centre – Carberry site (12 green manures/amendments)

 Canada Manitoba Crop Diversification Centre – Winkler site (compost)

Miami Soil Trial Setup

Treatments in 2007 Treatments in 2008 1 Spring wheat 3 Mustard Mix Potato 2 Oat/Pea 4 Pearl Millet Miami – Verticillium Propagules in Soil -2007

Before Manure After Manure

80 Spring 2007 Fall 2007

of soil of

- 60

10 No. of propagules g . propagules of No.

0 Control Mustards Oat/pea Pearl Millet Miami – Early Dying Incidence and SPAD - 2008

Spad Readings Early Dying Incidence

50 40 ns

40 ns 30 30 20 20

SPAD Units Units SPAD 10

10 Disease Incidence Incidence Disease (%) 0 0 Control Oat/pea Control Oat/pea Mustards Pearl Millet Mustards Pearl Millet Miami – Yield 2008 400 <2"1/4 2"4/4-31/2" >3"1/2 350 ns 300

-1 250

200

cwt.acre 150

100

0 Control Mustards Oat/pea Pearl Millet Shilo Trial – Green Manure

2008

Potato Shilo Soil – Verticillium Propagules Soil - 2007

Before Manure After Manure 100 Spring 2007 Fall 2007

of soil of

1 80

- ns 70 60 50 40 30 20

10 No. of propagules g . propagules of No. 0 Control Mustards Oat/pea Sorghum SPAD units SPAD and Early Dying Incidence 10 15 20 25 30 35 40 45 5 0

Control

Mustards ns Oat/pea

Shilo Sorghum

Soil Soil

Disease Incidence (%) 100 20 40 60 80 0 –

Control

Mustards

ns Oat/pea

2008 Sorghum

Sand Soil – Yield 2008 450 <1"3/4 1"3/4-2" >2"

400 ns

350 ns ns

300 -1 250 ns a a a 200 cwt.acre b 150

100 a ab 50 ab b 0 Control Mustards Oat/pea Sorghum Shilo Soil – Mustard Seed Meal 2008

Mustard Seed Meal Treatments 1 0% (control) 2 0.25% 3 0.5% 4 1% 5 0 (control) tarped 6 0.25% tarped 7 0.5% tarped 8 1 % tarped Shilo Soil - Effect on Verticillium germination - 2008 100 Week 1

Week 3 80

20 Germination of MS (%) MS of Germination

0 0 0.25 0.5 1 0 0.25 0.5 1

Non- covered Covered Treatments CMCDCField Study  3 years experiment

1st year 2nd year 3rd year Block IV 2006 2007 2008 Block II Green Manure Wheat Amendments Potato Block Wheat Wheat Potato III BlockWheat Wheat/Vapam Potato I Wheat Wheat Mustard meal/Potato Wheat Oriental mustard Potato Wheat Yellow mustard Potato Wheat Canada milk vetch Potato Wheat Sorghum/Sudan Potato Sorghum/Sudan Sorghum/Sudan Potato Wheat Oat/Peas Potato Wheat Fall – Rye Potato Wheat Compost/Wheat Compost/Potato Alfalfa Alfalfa Potato Soil Building Green Manures

Improve soil environment for plant growth and beneficial organisms in field Fall Rye

Promoting interactions between soil organisms for control of soil-borne pathogens

Alfalfa

Oat/Peas Composted cattle manure 44.5 wet ton.ha-1 Trap crops

Sorghum Sudan grass

“Trick pathogens to thinking host is available but then die” Toxicity to MS Canada Milk Decomposition of organic Vetch amendments can release volatile and non-volatile toxic compounds.

Biofumigation

Mustards Use of chemical that naturally occur in the Brassica family of plants to suppress soil-borne disease.

Mustard seed meal. 0.5% v/v. Verticillium Soil Population Determinations

Pathogen  Verticillium dahliae 1. Inhibition of microsclerotia. (Germination %)

2. Inoculum density. (# of microsclerotia . g-1 of soil) Germination of % 100 20 40 60 80

0 germination Control Wheat Mustard meal

Mustard meal

Vapam

Oat/peas

Vetch Milk Treatment Verticillium

(2 years) Sorghum s

Sorghum

(1 year)

Fallrye

mustard Oriental Mustards

mustard

Yellow

(2 years) Alfalfa

Verticillium Density in Soil

4545

4040

of soil of SpringSpring 2007 FallFall 2007 2007 Spring Spring 2008 2008Potato Potato harvest

3535 1

- harvestSpring 2007 Fall 2007 Spring 2008 3030

2525

2020

1515

1010

00 Sorghum Wheat CompostMustard Vapam Oat/peas Milk Sorghum Fall rye Oriental Yellow Alfalfa No. of propagules g . propagules of No. Control meal Vetch (2 years)(1 year) mustard mustard(2 years) Treatments Vertical bar = standard error. n=4 Verticillium Incidence 100 d Sorghum 90 Vapam Rye 80

c 70 c bc* bc bc 60 abc abc 50 Compost abc abc 40 30 ab Mustard meal 20 a

10 % % Incidence 0 Wheat Compost Mustard Vapam Oat/peas Milk SorghumSorghum Fall rye Oriental Yellow Alfalfa Control meal Vetch (2 years) (1 year) mustard mustard (2 years) Treatments *Means with different letters are significant different according to the Duncan’s protected least difference (P ≤ 0.05).

100

90 80 70 r=0.72 60 p<0.007 Pearson’s correlation coefficient 50 40 r for inoculum density of V. 30

20 % % Incidence dahliae and Verticillium wilt 10 incidence 0 0 5 10 15 20 25 30 35 40 No. of propagules . g-1 of soil

) 1

Effect on Total Tuber - 390 Yield 370 r=-0.82 350 p<0.001 330 310 Mustard Pearson’s correlation coefficient 290 270 seed meal r for potato yield and Yield (cwt.acre 250 Verticillium wilt incidence 0 10 20 30 40 50 60 70 80 90 100 % Incidence

350

Effect of green manure and organic amendments treatments on total tuber yield )

1 300450 - Fall 2008 Summer 2008 Harvest 400 Compost 250

- 350 * 200 300

Mustard 150250 1 seed meal 200 100

150

wt.acre Total N N (lb.acre Total 50100

50 0 Wheat Mustard Vapam Oat/peas Milk SorghumSorghum Fall rye Oriental Yellow Alfalfa 0 Compost meal Vetch (2 years)(1 year) mustard mustard(2 years) ControlWheat Compost Mustard Vapam Oat/peas Milk SorghumSorghum Fall rye Oriental Yellow Alfalfa Control meal TreatmentsVetch (2 years) (1 year) mustard mustard (2 years) Treatments Mustards Need Buildup of Toxic Product to Kill Verticillium Compost toAddition Winkler

cwt Yield acre-1 100 200 300 400 500 0 Burbank Russet Non-saline Composted cattle 80 ha manure Composted t Russet Umatilla Burbank Russet Saline Compost Check Russet Umatilla - CMCDC Soil CMCDC

Compost and Mustard Meal Addition to Winkler Soil

350

300

250

-1

200

150

cwtacre Yield 100

0 Check Mustard Meal Compost

Composted cattle manure 80 t ha-1; meal 10 t ha-1 2012 Fumigation and Compost Study

Russet Burbank Trial: 3 sites: Near Shilo, Carberry and Winkler

Standard Norland Trial: 3 sites: Near Morden, Winkler and Altona Site Locations

Trial 2

Trial 1

Trial 5 Trial 4 Trial 3 Trial 6 Treatments

Control (standard fertility) (CON) Composted Hog Manure 20 t ha-1 (CHM20) Composted Hog Manure 40 t ha-1 (CHM40) Composted Hog Manure 80 t ha-1 (CHM80) Composted Cattle Manure 20 t ha-1 (CCM20) Composted Cattle Manure 40 t ha-1 (CCM40) Composted Cattle Manure 80 t ha-1 (CCM80) High Fertility* (FERT) Vapam 40 gal acre-1 (VAP40) Vapam 60 gal ha-1 (VAP60) Vapam Application – Fall 2011

Shilo and Carberry Application

Other Applications Can You See An Effect?

Vapam (60 gal acre-1) Russet Burbank Yield - Winkler

Marketable yield Treatment Non- Total available N/kg soil Regular Bonus Overweight Total marketable CON 4.4 ± 0.5 9.7 ± 0.7 15.9 ± 2.8 2.5 ± 0.7 32.4 ± 3.8 45.3 ± 5.7 CCM20 5.5 ± 0.6 13.7 ± 0.5 13.1 ± 2.3 4.1 ± 1.3 36.3 ± 2.8 40.3 ± 3.0 CCM40 4.6 ± 0.6 9.8 ± 0.9 13.7 ± 1.9 5.0 ± 1.5 33.0 ± 3.6 45.3 ± 7.2 CCM80 4.5 ± 0.4 12.5 ± 0.6 15.3 ± 2.0 3.8 ± 0.9 36.0 ± 2.1 43.5 ± 5.1 FERT 4.7 ± 0.4 12.1 ± 0.7 13.3 ± 2.8 2.4 ± 0.5 32.5 ± 2.6 46.0 ± 11.2 VAP40 4.1 ± 0.5 11.7 ± 1.4 17.6 ± 2.5 5.1 ± 0.8 38.5 ± 3.0 47.5 ± 5.2 VAP60 4.5 ± 0.5 11.4 ± 1.4 20.1 ± 2.7 5.8 ± 1.2 41.8 ± 3.5 49.3 ± 7.2 Russet Burbank Yield - Shilo

Marketable yield Treatment Incidence (%) Non-marketable Regular Bonus Overweight Total

CON 6.7 ± 0.7 20.2 ± 2.6 17.7 ± 2.5 4.0 ± 1.3 48.6 ± 3.5 45 ± 23

CCM20 4.8 ± 0.8 18.4 ± 1.6 19.9 ± 2.2 3.2 ± 0.8 46.3 ± 1.6 15 ± 6

CCM40 7.1 ± 1.3 20.2 ± 0.9 21.0 ± 1.3 6.1 ± 2.0 54.3 ± 2.5 30 ± 13

CCM80 6.3 ± 0.8 17.1 ± 1.6 19.6 ± 3.3 4.1 ± 1.8 47.2 ± 4.5 37.5 ± 9

FERT 7.4 ± 1.1 18.8 ± 2.6 17.3 ± 2.1 3.5 ± 0.5 47.0 ± 5.0 32.5 ± 21

VAP40 8.1 ± 1.8 19.8 ± 2.6 24.5 ± 2.0 3.7 ± 1.6 56.1 ± 2.5 5 ± 3

VAP60 7.6 ± 1.1 18.6 ± 1.9 19.7 ± 1.1 4.8 ± 2.0 50.6 ± 4.2 12.5 ± 5 Our Past Fumigation Results

• Three previous trials with Metam Sodium • 40-70% reduction in Verticillium soil levels • Yield responses variable • No compelling evidence to improve yield • But growers and processers interested MB Fumigation Trial 2016

• Three fields fumigated late fall 2015 with Busan • Two fields done with commercial applicator (Fields 1 and 3) • One field done with plot applicator (Field 2) • Soil samples taken pre-treatment, following spring and at harvest • Vert counts, qPCR V. dahliae and V. tricorpus • Visual disease ratings prior to harvest • Hand digs for yield, classes and quality Field Fumigation Field 2

Field 3 Field 1 Harvest 2016

Vasc. Gross yield Net yield Field Treatment Vert #/g Wilt Colour cwt/ac cwt/ac 1 Busan 16 497 422 Control 29 466 396

2 Busan 414 0.48 0.69 481 458 Control 522 2.9 3.14 397 372

3 Busan 65 1.77 0.70 431 366 Control 149 2.20 1.65 447 380

* Value pairs in boxes are significantly different at P< 0.05 Field 2 V. dahliae PCR (copy #/g)

Treatment Fall 2015 Spring 2016 Fall 2016 Spring 2017 Fumigated 87,035 60,207 132,129 468,667 Non-fumigated 110,765 195,801 349,637 407,759

Potato Crop Year Before fumigation Spring After Potato Fumigation Trials 2017 – Site 1 V. dahliae copy #/g soil Prior to fumigation Spring following fumigation Location Fumigated Un-fumigated Fumigated Un-fumigated 1 31077 253163 68437 168027

2 142594 145191 57714 478029

3 337327 212115 174099 609636

4 103408 151346 144751 632791

5 235103 227998 163322 590465

6 100464 159192 247716 389069

7 41558 63402 208656 145782

8 87849 20236 25507 40997

9 39014 3967 52068 34902

10 7783 14587 32471 33447

11 16432 BD 19894 50430

12 209074 49332 210392 440285 Fumigation Trials 2017 – Site 2 V. dahliae copy #/g soil Location Fumigated Un-fumigated Fumigated Un-fumigated 1 11384 12625 28984 158748

2 21856 28912 38187 37030

3 68767 70569 49192 91672

4 162385 47784 20347 191841

5 91628 128497 49426 218512

6 44455 79738 41045 242209

7 65970 112972 45821 174099

8 3948 67537 19087 98651

9 21856 21659 39473 33685

10 27603 23920 37693 80864

11 19683 51146 BD 168325

12 77049 118828 28984 158748 Fumigation Conclusions • 1 of 3 fields had very high Verticillium dahliae soil levels • 2 of 3 fields Busan fumigation reduced Verticillium dahliae levels in soil • Field with very high Verticillium had reduced disease and increased yield with fumigation • Yield loss due to Early Dying from Verticillium was 19% reduction in 1 of 3 fields • Verticillium levels bounce back year after potato • Fumigation may rescue fields with high Verticillium levels • Fumigation in other fields is likely waste of $ • Outstanding question – would fumigation be required every year for rescued fields? Controlling Root Lesion Nematode

Marigold Green Manures

Pudasaini et al. 2006 Forage Pearl Millet

Belair et al. 2005 Atlantic Canada

PEI Yield Variability Study Year Soil Measure with Good Areas > 10% Response Relative to Bad Between Good Yielding Areas (%) and Bad Yield Areas 2014 V. albo-atrum 74 Sodium 82 Phosphate 89 2015 Zinc 113 2016 Potassium 115 > 100% means soil measure increased in the Low Yielding Areas

Raw Data Source: Genesis Crop Systems Inc and PEI Potato Board 2017 PEI Nematode Survey

Population in Positive Samples (#/kg soil) 3000 2500 2000 1500 1000 Of Interest: 500 0 Root-lesion (several species, one aggrevates PED) Cyst (could be Oat or Soybean Cyst Nematode, watch for Potato Cyst % Fields Positive for a Type of Nematode) Nematode Root-knot (likely Northern Root-knot, affects 120 tuber quality) 100 80 60 40 20 0 Bernie’s Fumigation Trial

Site Treatment Visual RLN #/kg Vert count V. dahliae MRK Yield #/g DNA pg/g cwt A16-1 Control 6.7 1014 204 157 408 Pic+ 6.6 1258 5 44 426

B16-1 Control 6.8 3713 350 Pic+ 7.0 1237 374

D16-1 Control 6.8 2320 322 Pic+ 6.8 1573 378

M16-2 Control 4.5 4948 15.2 2266 340 Pic+ 6.6 804 1 569 393 Examining Effect of Disease- Suppressive Crops • Large field in Kings County • 2017: Russet Burbank for table market • Total of 6 strips, including o 2015 soy, 2016 winter wheat (control) o 2015 brown mustard / 2016 brown mustard o 2015 buckwheat / 2016 buckwheat o 2015 fallow / 2016 fallow o 2015 fallow / 2016 mustard o 2015 brown mustard / 2016 buckwheat Marketable Yield adjusted for equal number of plants/strip

450.0 404.5 409.1 400.0 337.7 350.0 324.8

300.0 273.8 271.8 250.0

200.0

150.0

100.0

50.0

0.0 soy-ww bw-bw mus-mus fallow fallow-mus mus-bw Wireworm Damage measured in incidence level per 10 tubers

5.0 4.5 4.5

4.0

3.5

3.0

2.5 2.3 2.0 1.8 1.5 1.5 1.0 1.0 0.5 0.5

0.0 soy-ww bw-bw mus-mus fallow fallow-mus mus-bw Wireworm Damage measured in holes/tuber

2.5

2.0 2.0

1.5

1.0

0.5 0.3 0.4 0.3 0.1 0.0 0.0 soy-ww bw-bw mus-mus fallow fallow-mus mus-bw Results Discussion

• Treatments with mustard, buckwheat, or both were noticeably higher in total yield and marketable yield than control (soy/ww) • Rotations with fallow had similar reductions in wireworm damage to mustard/buckwheat, but yields more similar to control. • Have not yet applied statistics to this data. Also adjusted raw data to 7 plants per 10 ft strip (some had 8 or 9) • Yields found in strips similar to yield data from the grower. Conclusions

• Atlantic Canada has V. dahliae and P. penetrans in high levels • Likely better treatment responses than MB • Rotation crops are hosts • Tight rotations a problem • Understand soil properties (health) to PED the future • Chloropicrin increases yield • Don’t know long-term effect of chloropicrin • Can we fumigate then soil-build? • Know benefit of nematode control • Know benefit of nematode and Verticillium control

• Know importance of V. albo-atrum • Know species of Pratylenchus present • Careful mustards may increase P. penetrans levels • Forage Pearl Millet should be examined • Mustard meals are expensive and tough to source. Can work but watch N levels • Compost may be useful in poor health soils

Oscar MolinaAcknowledgements Scott Graham Terri Fairman Manitoba Seed Producer cooperators Potato Growers Gaia Consulting Delta Ag Consulting MHPEC Inc. Blair Geisel Fouad Daayf PEI Potato Board and Ryan Barrett

@soilecologyUMan

Soil Ecology University of Manitoba