Manitoba weed resistance update –Results of the 2016 field survey and management questionnaire

Hugh J. Beckie and Julia Y. Leeson

Saskatoon Research & Development Centre

hugh.beckie@agr.gc.ca

Top 10 weeds in Manitoba: 2016 survey (pre-harvest, 659 fields)

• 10: Malva pusilla (round-leaved mallow) (17th in 2002)• 9: Volunteer wheat (12th in 2002)• 8: Amaranthus retroflexus (redroot pigweed) (6th in 2002)• 7: Taraxacum officinale (dandelion) (9th in 2002)• 6: Setaria pumila/glauca (yellow foxtail) (32nd in 2002)• 5: Volunteer canola (10th in 2002)• 4: Avena fatua (wild oat) (2nd in 2002)• 3: Echinochloa spp. (barnyard grass spp.) (4th in 2002)• 2: Polygonum convolvulus (wild buckwheat) (3rd in 2002)• 1: Setaria viridis (green foxtail) (no change)

65

1957--- 7

BCAB

SKMB

ON QC

NBNS

PE

NF&LD

YTNT

NV

123 20 22

35 3

Unique HR weed cases

The rising incidence of HR weeds in western Canada

M ha / M ac2001 - 2003 surveys: 4.4 / 10.92007 - 2009 surveys: 9.9 / 24.42014 - 2017 surveys: 15.4 / 38.0 (projected)

Sam

ples

(no.

)

Year

Submissions to the CPL

Sam

ples

(no.

)

Submissions to the CPL: by province

• 151 fields in 74 municipalities

• Fields• Wheat: 47• Barley: 6• Oat: 6• Corn: 7• Canola: 45• Flax: 8• Soybean: 30• Sunflower: 2

2016 Manitoba HR weed survey

• 102 of 151 fields have an HR weed (68%)

• This compares with 48% in 2008 and 32% in 2002 in Manitoba

• The recent Saskatchewan survey (2014/15) indicated 57% of fields with an HR weed

2016 Manitoba HR weed survey

• HR biotype # fields total fields sampled % # municipalities (74)• Gp 1 wild oat 79 101 78 51• Gp 2 wild oat 43 101 43 34• Gp 1+2 wild oat 42 101 42 33• Gp 1 green foxtail 22 50 44 18• Gp 2 green foxtail 3 50 6 3• Gp 1+2 green foxtail 1 50 2 1• Gp 1 yellow foxtail 19 60 32 16• Gp 2 yellow foxtail 10 60 17 8• Gp 1+2 yellow foxtail 4 60 7 4• Gp 2 barnyard grass 3 11 27 3

____________________________________________________________

MB 2016 HR weed survey: grass weed resistance

Yellow foxtail: the surprise!

Yellow foxtail

Green foxtail

• HR biotype # fields total fields sampled % # municipalities (74)• Gp 2 cleavers 2 18 11 2

• Gp 2 wild mustard 3 12 25 3

• Gp 2 redroot pigweed 1 22 5 1

• Gp 2 shepherd’s-purse 1 2 50 1_____________________________________________________________

MB 2016 HR weed survey: BL weed resistance

Baseline GR kochia survey in Saskatchewan in 2013: 17 of 342 sites (5%)

*

Montana North Dakota

2013 Manitoba: 2 of 283 sites sampled

USA

Time In (d)

Viab

le k

ochi

a se

ed (%

)

T50 =208 dT90 =235 d

Oct. 15

GR kochia seed persistence, Lethbridge 2014-2016

Time In (d)Viab

le k

ochi

a s

eed

(%)

Oct. 15

T50 =213 dT90 =228 d

GR kochia seed persistence, Scott, SK 2014-2016

Cum

ulat

ive

germ

inat

ion

(%)

Time (d)

GR kochia germination

Cum

ulat

ive

first

leaf

(%)

Time (d)

GR kochia: early growth

Multiple-resistant wild oat

86

98

85

66

95

88

0 20 40 60 80 100

tralkoxydim (1)

clodinafop (1)

pinoxaden (1)

pyroxsulam (2)

imazamethabenz (2)

flucarbazone (2)

% Resistant Seeds

Year Crop Wild oat herbicides

2004 Wheat clodinafop2005 Wheat fenoxaprop

2006 LL Canola

glufosinate/clethodim + clethodim

2007 Barley pinoxaden + tralkoxydim2008 Barley imazamethabenz

2009 RR Canola glyphosate + glyphosate

2010 Wheat triallate/trifluralin + clodinafop

2011 Field pea ethalfluralin + quizalofop2012 Wheat pyroxsulam

2013 LL Canola Glufosinate/clethodim

Wheat & barley herbicide options: Gp 1+2-resistant wild oatAltitude FX (FX2) (CL) – imazamox (2)Assert – imazamethabenz (2)Aurora – clodinafop (1)Avadex – triallate (8) PREAvert – imazamethabenz (2)Axial (iPak, Xtreme) – pinoxaden (1)Bengal WB – fenoxaprop (1)Bison – tralkoxydim (1)Broadband – pinoxaden (1)Bullwhip – clodinafop (1)Cordon – fenoxaprop (1)Cougar – fenoxaprop (1)Everest GBX (2.0) – flucarbazone (2)HellCat – fenoxaprop (1)Horizon NG – clodinafop (1)Ladder – clodinafop (1)Foax – clodinafop (1)Foothills NG – clodinafop (1)

Fortress MicroActiv – trifluralin (3), triallate (8) -PREInferno Duo – fluracarbazone (2)Liquid achieve – tralkoxydim (1)Marengo – tralkoxydim (1)NextStep NG – clodinafop (1)Nufarm Tralkoxydim Liquid – tralkoxydim (1)Predicade – thiencarbazone (2)Puma Advance – fenoxaprop (1)Sierra 2.0 – flucarbazone (2)Signal (FSU) – clodinafop (1)Simplicity 30 OD (GoDRI) – pyroxsulam (2)Slam’R – clodinafop (1)Traxos (Two) – pinoxaden + clodinafop (1)Tundra – fenoxaprop (1)Varro – thiencarbazone (2)Velocity m3 – thiencarbazone (2)Vigil WB – fenoxaprop (1)WildCat – fenoxaprop (1)

Top 10 HRWM practices

• 10: Maintaining a database: invaluable reference• 9: Strategic tillage: if, where, or when needed • 8: Field & site-specific weed mgmt: 1 size may not fit all• 7: Weed sanitation:border control and slowing HR dispersal• 6: In-crop wheat-selective herbicide rotation: combating NTSR• 5: Herbicide gp rotation: avoid back-to-back in-crop gp 1 or 2 • 4: Herbicide mixtures/sequences: better than rotations• 3: Pre- and post-herbicide scouting: know your enemy• 2: Competitive crops & practices that promote competitiveness:

natural biological control• 1: Crop diversity

Top 10 weed management practices2015 SK grower questionnaire (n = 600 respondents)

Adoption (%)0 10080604020

Scouting: before in-crop tmtPOST herbicide tmt

Herbicide tmts overallCrop rotation

Scouting: before PRE tmt Tank-mixing herbicides

Scouting: before fall tmtHerbicide SOA rotation

PRE herbicide tmtScouting: after in-crop tmt

Weed management practices: # 11 - 20

Scouting: after PRE tmtGrow competitive crops

Scouting: after fall tmtSanitation: tarping truck box

Fall herbicide tmt Pre-harvest herbicide tmt

Increase seeding rateCompetitive crop varieties

Sanitation: cleaning equipmentNarrow crop row spacing

Adoption (%)0 10080604020

Top 10 weed management practices2016 MB grower questionnaire (n = 108 respondents)

Adoption (%)

Weed management practices: # 11 - 20

Adoption (%)

Crop rotationHerbicide SOA

rotationTank-mixing

herbicidesPRE herbicide tmt

Adoption (%)0 10080604020

HRWM practices2015 SK grower questionnaire (n = 250 respondents)

Overall, those with HR weeds rely more on herbicides at all application windows, and have greater adoption of: • scouting before in-crop herbicide treatment• tank-mixing herbicides • herbicide SOA rotation • growing weed-competitive crops• increasing crop seeding rates vs. those without resistance

HRWM practices2016 MB grower questionnaire (n = 48 respondents)

Overall, those with HR weeds rely more on herbicides at all application windows, and have greater adoption of: • scouting before in-crop herbicide treatment• tank-mixing herbicides • herbicide SOA rotation • growing weed-competitive crops• tillage• vs. those without resistance

Adoption (%)

The cost of weed resistance in Saskatchewan: 2015

% of respondents (250-SK)No additional cost 7$10/ac or less 41 ($24.70/ha or less)$11 - $20/ac 23 (- $49.40/ha)$21 - $30/ac 11 (- $74.10/ha)$31 - $40/ac 6 (- $98.80/ha)$41 – 50 /ac 4 (- $123.50/ha)Unknown cost 8

Mean cost = $12 per acre or $30 per hectare

The cost of weed resistance in Manitoba: 2016

% of respondents (50-MB)No additional cost 5$10/ac or less 56 ($24.70/ha or less)$11 - $20/ac 23 (- $49.40/ha)$21 - $30/ac 9 (- $74.10/ha)$31 - $40/ac 7 (- $98.80/ha)$41 – 50 /ac 0 (- $123.50/ha)Unknown cost 0

Mean cost = $11 per acre or $27 per hectare

AlbertaSaskatchewan Manitoba

Annual crop area: 70 M ac

Top 5 crops (M ac)Canola: 22.8Wheat: 21.2Barley: 5.5Lentil: 4.4Field pea: 4.1

HR canola in rotation: - ca. ½ RR; ½ LL (2012-2014 crop years)

• (220 respondents) %

• Canola 1 in 2 yr 46

• Canola 1 in 3 yr 23

• Canola 1 in 4 yr or less 17

• Continuous canola 4

• No canola 10

Net return: $/ac (2017):Wheat: 95Canola: 178Barley (malt): 69Lentil: 275Field pea: 103

Albertafall, 2017

fall, 2015

fall, 2016

Conclusions

• Continual weed resistance surveillance via field surveys and submission sample testing is a continuing high priority

• Present (kochia) and future weeds (?) with glyphosate resistance is and will be an important focal point of research

• BUT…. overall, wild oat (multiple) resistance will continue to be the #1 HR weed problem across western Canada

• Consistent application of BMPs is the best long-term strategy (tortoise vs. hare fable)

• W. Canada producers are now using a number of these BMPs – but we need new tools soon!