Fight the Light: Reducing Herbicide Dependence with Agronomy

François Tardif, Mike Cowbrough, Peter Smith

2010 – 1 County with glyphosate resistant Canada fleabane

2015 – 28 Counties with glyphosate resistant Canada fleabane

Herbicide Options in Soybean:

• Emerged fleabane MUST be controlled BEFORE PLANTING

• ERAGON + MERGE + SENCOR (216 g/ac) most consistent at doing so

12

73

84

97

0 20 40 60 80 100

glyphosate

plus 2,4-D Ester

plus ERAGON & MERGE

plus ERAGON & MERGE & SENCOR(216 g/ac)

Average Control Achieved

% VISUAL CONTROL

Canada Fleabane – PRE (SOYBEAN)

34

95

99

100

0 20 40 60 80 100

glyphosate

plus 2,4-D Ester

plus ERAGON & MERGE

plus ERAGON & MERGE & SENCOR(216 g/ac)

Highest Control Achieved

% VISUAL CONTROL

Canada Fleabane – PRE (SOYBEAN)

Eragon + Merge

P.H. Sikkema, UofG

2

18

28

92

0 20 40 60 80 100

glyphosate

plus 2,4-D Ester

plus ERAGON & MERGE

plus ERAGON & MERGE & SENCOR(216 g/ac)

Lowest Level of Control Achieved

% VISUAL CONTROL

Canada Fleabane – PRE (SOYBEAN)

Fleabane control with Sencor

Sencor @ 300 g/ac

Sencor @ 450 g/ac

Sencor @ 600 g/ac

P.H. Sikkema, UofG

INFINITY

P.H. Sikkema, UofG

0 20 40 60 80 100

Estaprop

Trophy

2,4-D Ester 700

Infinity

High

Average

Low

% VISUAL CONTROL

Canada Fleabane – POST (WHEAT)

PRE: Dicamba based herbicides (Battalion, Banvel II and Marksman)

0 20 40 60 80 100

Integrity

Callisto + Aatrex

Banvel II

Marksman

High

Average

Low

% VISUAL CONTROL

Canada Fleabane – PRE (CORN)

POST: Banvel II or Marksman

0 20 40 60 80 100

Callisto + Aatrex

Distinct

Pardner + Aatrex

Banvel II

Marksman

High

Average

Low

% VISUAL CONTROL

Canada Fleabane – POST (CORN)

If you have this plant in your fields…

Most effective options for Canada Fleabane

• Soybeans – Eragon + Sencor – applied during the day

• Cereals – Fall applications (Eragon, Infinity) – Spring (Infinity, 2,4-D)

• Corn – Soil applied (Marksman, Integrity, Battalion, Callisto +

Aatrex, Banvel II)

If you’ve never seen this plant…

12

73

84

97

0 20 40 60 80 100

glyphosate

plus 2,4-D Ester

plus ERAGON & MERGE

plus ERAGON & MERGE & SENCOR(216 g/ac)

Average Control Achieved

% VISUAL CONTROL

Canada Fleabane – PRE (SOYBEAN)

Proactive action against resistance is rare, reactive action is the norm…

CWSS 2015

Response to herbicide resistance

Denial

Response to herbicide resistance

Denial

First line of defense

New herbicides

From one herbicide to another

Photos: P. Sikkema

Multiple resistance

New MoA

Cultural Methods

Cultural methods are known…

“There is a need to demonstrate the value of enhanced agronomic practices to combat resistance…”

Rotation trial Low intensity

High intensity

Limited rotation

30” rows

34,000 plants/acre

Spring tilled

15” rows

177,000 plants/acre

Fall and spring vertical tilled

Typical rotation

30” rows

Spring tilled

15” rows

Fall and spring vertical tilled

Short variety

1.5 M seeds/acre

No till

34,000 plants/acre 177,000 plants/acre

High density rotation

75 cm rows

Spring tilled

18 cm rows

No till

Tall variety

1.8 M seeds/acre

No till

Preplant MAP Seed placed MAP

41,000 plants/acre 225,000 plants/acre

“Fight the Light” rotation

75 cm rows

Spring tilled

18 cm rows

No till

Tall variety

1.8 M seeds/acre

No till

Ryegrass/crimson clover Red clover

Preplant MAP Seed placed MAP

41,000 plants/acre 225,000 plants/acre

Light attenuation / soybeans

0

0.2

0.4

0.6

0.8

1

1.2

145 165 185 205 225 245 265

Lightex

nconcoefficient

Days

LowPop.,WideRow,NoN

HighPop.Narr.Row,ExtraN

0.0

0.2

0.4

0.6

0.8

1.0

1.2

145 165 185 205 225 245 265

Ligh

tex

nconcoefficient

Days

LowPop.,WideRow,NoN

HighPop.Narr.Row,ExtraN

2014 2015

Yield / soybeans

0

0.5

1

1.5

2

2.5

Limited Typical High Density Fight the Light

Yie

ld (

Ton

s/h

a)

Soybeans 2014

0

0.5

1

1.5

2

2.5

Limited Typical High Density Fight the Light

Yie

ld (

Ton

s/h

a)

Soybeans 2015

Soybeans high density

Soybeans low density

POTASH DEFICIENCY: ~ 60 PPM K (soil test)

Fertility affects canopy closure

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

27-Jun 04-Jul 11-Jul 18-Jul 25-Jul 01-Aug 08-Aug 15-Aug 22-Aug

soybean - adequate K

Fertility affects canopy closure

21% in 2015

Reduction in light interception: 40% in 2014

0.0

0.2

0.4

0.6

0.8

1.0

1.2

145 165 185 205 225 245 265

Lightex

nconcoefficient

Days

LowPop.

HighPop.

0.0

0.2

0.4

0.6

0.8

1.0

1.2

150 170 190 210 230 250

Lightex

nconcoefficient

Days

LowPop.

HighPop.

Light attenuation / corn

2014 2015

0

2

4

6

8

10

12

Limited Typical HighDensity FighttheLight

Yield(To

ns/ha)

Corn2014

Yield / corn

34,000 plants/ac– herbicide applied @ 2 leaf Yield: 145 bu/ac

41,000 plants/ac – herbicide applied @ 2 leaf Yield: 155 bu/ac

41,000 plants/ac – herbicide applied @ 2 leaf Seeded with ryegrass + crimson clover at 9 leaf stage

Yield: 152 bu/ac

0

0.2

0.4

0.6

0.8

1

1.2

145 165 185 205 225 245

Lightex

nconcoefficient

Days

LowPop.

HighPop.

Light attenuation / wheat

0.0

0.2

0.4

0.6

0.8

1.0

1.2

145 165 185 205 225 245 265

Lightex

nconcoefficient

Days

LowPop.

HighPop.

2014 2015

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Typical HighDensity FighttheLight

Yield(To

ns/ha)

Wheat2014

Yield / Wheat

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Typical HighDensity FighttheLight

Yield(To

ns/ha)

Wheat2015

*

Summary

Small differences in canopy closure

Summary

No yield impact

Summary Controlling all agronomic factors is important

Conclusions

Not as easy as some say

What else can we do?

• Practices that cost nothing and may provide some benefit to weed management…

51%

Weed biomass reduced by 51%

PLANT EAST/WEST

24% Wheat yields increased by 24%

PLANT EAST/WEST

NIGHT TILLAGE

What else can we do?

• Practices that increase cost of production and may provide a return on investment while decreasing weed populations.

Intensive Management Increased Corn Yield by 24 bu/ac at Elora ON

INTENSIVE MANAGEMENT PRACTICE

38,000 plants/acre

Nitrogen calculator rate plus 35-50 lbs N/acre

Fungicide (Priaxor) @ 120 mL/acre applied at silking

2014 Weed Control in Corn Treatments

34,000 plants/acre 41,000 plants/acre

“Reduced weed biomass by 56%”

Warren Schneckenburger, 2015

FUTURE RESEARCH…

Summary Good weed control relies heavily on:

1. Adequate fertility

2. Quick Crop Establishment (crop emerges first)

3. Timely weed control (Tillage or Herbicides)

Keep weed-free: – from emergence to 6 leaf (corn)

– from emergence to 2 trifoliate (soybean)

Summary

• There is no “silver bullet” when it comes to cultural control.

• Seed destruction is an area that shows promise.

Thanks to:

Meghan Grguric Tasha Valente Peter Johnson Horst Bohner Greg Stewart