2015 hres- ikc-ballarat- 25 june vic

Herbicide resistance in Victoria

Dr Peter Boutsalis, Plant Science Consulting &

University of Adelaide

IKC- June 25 2015

Plant ScienceConsulting

Outline

Why does herbicide resistance occur Frequency of resistance Ryegrass Wild oats Broadleaf weeds Glyphosate resistance Herbicide resistance testing Integrated weed management

Why does herbicide resistance occur?

Herbicides don’t cause resistance!!

Resistance is naturally present.

Herbicides select and enrich resistance

poor spray conditions= low rate= weak resistance

mechanisms stack

Ryegrass/ wild radish- obligate outcrossing so

combine weak resistance strong resistance

Frequency of resistance

Frequency of resistance

Group A: 1 in 500,000 naturally resistant

Group B: 1 in 20,000 naturally resistant (25X)

Group M: very rare but its here!

Frequency of Group A Resistant Individuals in a 100 ha Paddock

Plant Density

1 m-2

10 m-2

100 m-2

1000 m-2

Plants

1 million

10 million

100 million

1 billion

Resistant Individuals

2

20

200

2000

(assume a frequency of 1 R/ 500,000 plants)

So a paddock with a low density of survivors may not look threatening but if they are resistant resistant seedbank!!

How Soon Does Resistance Happen? - Rules of Thumb

Herbicide Group Years to resistance

B- Glean 4

A- Hoegrass 6-8

C- Simazine 10-15

D- Trifluralin 10-15

F- Brodal ~10

L- Sprayseed >12

M- Glyphosate ~15

Incidence of Herbicide resistance across south-eastern

Australia

Herbicide Resistance Surveys

Sampling– End of season – Collect seed from paddocks

randomly over a wide geographic area

– Frequency 5-10 km

Evaluation- Pot testing– Pot testing in winter

Resistance levels change so need to revisit (eg 5 yr interval)

Uni of Adelaide random weed surveys between 2004-2012(paddock surveyed)

Testing of survey samples

Ryegrass

Ryegrass resistance in West-Victoria

Western Victoria Results of weed survey of 125 paddocks chosen at random in 2005 & 2010 conducted by the University of Adelaide. Paddocks were scored as resistant if the seeds collected exhibited >20% survival in a pot test conducted the following winter. Thus samples that exhibited 1% to less than 20% survival were scored as non-resistant.

Ryegrass resistance in N-Victoria

Northern Victoria Results of weed survey of 120 paddocks chosen at random in 2006 & 2011 conducted by the University of Adelaide. Paddocks were scored as resistant if the seeds collected exhibited >20% survival in a pot test conducted the following winter. Thus samples that exhibited 1% to less than 20% survival were scored as non-resistant.

Status of herbicide resistance in ryegrass

NSW & Tasmanian results courtesy of John Broster (Charles Sturt University)WA results courtesy of AHRI, University of Western Australia

Resistance defined where ≥ 20% survival in a pot test

Relationship within Group A’s and B’s in resistant ryegrass

Ryegrass resistance- Group A’sFOPS DEN DIM

If resistant to below: Hoegrass Verdict Targa Axial Achieve Select Factor

Hoegrass - R R ? ? ? ?

Verdict R - R ? ? ? ?

Targa R R - ? ? ? ?

Axial R R R - R ? ?

Achieve R R R R - ? ?

Select R R R R R - ?

Factor R R R R R R -

Rate response: Select, Factor, Select + Factor

Ryegrass resistance- Group B’sSulfonylureas IMI’s TP’s

If resistant to below: Logran Glean Hussar

(ryegrass)Atlantis

(wild oats)Intervix/ OnDuty Crusader

Logran - R ? ? ? ?

Glean R - ? ? ? ?

Hussar R R - R ? R

Atlantis R R R - ? R

Intervix R R R ? R ? - R ?

Crusader R R R R ? -

Why isn’t ryegrass controlled with Select?

Distribution of Group A resistance using molecular studies

2078 25

2041 3

2078, 2041 11

2078, 2088 5

2041, 1781 1

1781, 2041, 2078

1

2041, 2078, 2088

1

Paddock 1

• “Resistance occurs from a single plant in a paddock” is unlikely for Group A and B’s

Paddock 2 Paddock 3

ACCase Target site mutations

Mutation 1998 2003 2008 1781 6 8 13 2027 10 7 6 2041 40 32 43 2078 13 13 21 2088 11 6 19 2096 1 1

1781, 1999 1 1781, 2027 1 1781, 2041 3 2 14 1781, 2078 3 3 1781, 2096 2 1999, 2041 1 1999, 2078 3 2027, 2041 2 2 2027, 2078 3 2041, 2078 3 5 4 2041, 2088 1 3 2078, 2088 6 3 2078, 2096 2 2088, 2096 1

Distribution of ACCase mutations

in SA

Herbicide tactics at different stages to control weeds

Knockdowns (don’t overuse Gly) vs RR-canola

Rotate between different modes of action

Trifluralin, Avadex, Boxer Gold, Sakura, Kerb (IBS)

In-crop (Group A & B’s) resistance. Opportunities

exist- use Herbicide Resistance Testing

Seed-set: Crop topping- “canola”, pulses, wheat

NEW HERBICIDES

Adelaide University is investigating:

New MoA herbicides selective in wheat & canola

New non-selective knockdown herbicide

Life Impact The University of Adelaide

Product X applied IBS


New pre-em herbicide research

Herbicide Resistance in Wild oats


Resistance in wild oats

• Group A resistant- big problem in northern NSW/ southern QLD.

• Group B’s- increasing

• What is the info from random surveys?

Herbicide Resistance in Wild Oats from Random Surveys

HERBICIDE West Victoria NE Victoria

Data is % of random samples (Resistance = survival ≥20%)

2005 2010 2006 2011

Paddocks 35/ 112 (31%) 38/ 121 (31%) 85/ 118 (72%) 40/115 (35%)

Topik 10 10 8 8

Verdict - 5 - 0

Axial - - 2 -

Atlantis - 0 0 0

Mataven - 2 12 5

Select 0 - 0 -

Wild Oats resistance- Group A’sFOPS DEN DIM

If resistant to below: Topik Verdict Targa Axial Achieve Select Factor

Topik - ? ? ? ? ? ?

Verdict R - R ? ? ? ?

Targa R ? - ? ? ? ?

Axial R ? ? - R ? ?

Achieve R ? ? R ? - ? ?

Select R ? ? ? ? - ?

Factor R ? ? ? ? R? -

Rate response: 150ml/ha Axial vs 300ml/ha AxialCrop-topping with Topik/ Axial

Photos

Axial regrowth

300 vs 150ml Axial

Avadex

Wild oats resistance- Group B’sSulfonylureas IMI’s TP’s

If resistant to below:

Hussar (ryegrass)

Atlantis (wild oats)

Intervix/ OnDuty Crusader

Hussar - R? ? R?

Atlantis R - ? R?

Intervix (Clearfield) R R - R

Crusader R R ? -

Differences between ryegrass and wild oats

Ploidy- 2 vs 6 copies of each gene

Pollination- cross vs self

Seeds/ plant

Is frequency of resistance different between species?

Managing broadleaf weed resistance

wild radish,

Indian hedge mustard,

sowthistle

BLW issues in Victoria

Wild radish- resistance to Group B/I/F

Milk thistle- resistance to Group B (I/M)

Mustards- Group B (C/F/I)

Glyphosate resistance confirmed in NSW

Wild Radish

Genetically diverse like ryegrass.

Cross pollinates so resistance genes are transferred (= ryegrass)

Seedbank life: (6-8+ yr) exposure to same MoA. Not all seeds

germinate in following year.

Stacking of resistance (multiple resistance) = ryegrass

Resistance starting in eastern Australia

Rotate MoA groups B, C, F, H, I, even if cheaper herbicides working

Use full rates!!

Spray early- younger resistant weeds can be killed


Glyphosate Resistance

Christopher Preston, Jenna Malone and Peter Boutsalis

School of Agriculture, Food & Wine, University of Adelaide


What we have so far

Annual ryegrass Barnyard grass Liverseed grass

Fleabane Windmill grass Great brome


Glyphosate resistant ryegrass

Situation Number of sites

States

Broadacre cropping

Chemical fallow 29 NSW

Winter grainsIrrigated crops

821

Vic, SA, WA, NSWSA

Horticulture Tree crops 5 NSW, SAVine cropsVegetables

212

SA, WAVic

Other Driveway 4 NSW, Vic, SA, WAFence line /Crop marginAround buildings

632

NSW, SA, Vic, WANSW

Irrigation channel /Drain

12 NSW, SA, Vic

Airstrip 1 SARailway 2 WA, NSWRoadside 85 SA, NSW, WA

One population = 10L/ha (roadside in southern Vic).

Plant ScienceConsulting

1000ml/ha 1500ml/ha

Increasing rates of Glyphosate

1000ml/ha 1500ml/ha


Control of Gly-R ryegrass on fence lines with herbicide mixtures

0

50

100

150

200

250

300

Herbicide treatment

See

d h

ead

s/m

2

Un

trea

ted

Gly

ph

osa

te

Gly

ph

osa

te

mix

ture

s

Par

aqu

atm

ixtu

res

Exp

erim

enta

l

Do

ub

le k

no

ck2L/ha glyphosate

2 applications of Spray.Seed


Glyphosate resistance along fenceline in crop

Response of in-crop ryegrass to glyphosate

405 810 16200

10

20

30

40

50

60

70

fence line 15m in crop 30m in crop 50m in crop

Glyphosate rates (g a.e ha-1)

% S

urv

iva

l

Glyphosate resistance

What are your herbicide options?

Resistance testing

www.plantscienceconsulting.com.au

PLANT SCIENCE CONSULTING

What tests are there?

1. During the growing season• Syngenta Herbicide Resistance Quick-Test• Test for resistance on surviving weeds• Grasses mainly• 4-5 weeks

2. At end of season (pre-harvest)• Seed testing• 8-10 weeks• Dormancy breaking easy (wild radish, wild oats, ryegrass etc.)• Seedlings transplanted

3. Crop Seed Quality Testing•Germination, Vigor, TSW, •Clearfield testing- wheat/ barley/ canola

PLANT SCIENCE CONSULTING

www.plantscienceconsulting.com

Testing: www.plantscienceconsulting.com.au

Testing Plants Testing Seed

Results using Seed Testing

Herbicide Product Rate

Herbicide Group

Farmer paddock

(g or ml/ha)Surviva

l(%)

Rating

Verdict + 1% Hasten 85 A-FOP 70 RR

Select + 1% Hasten 250 A-DIM 20 R

Select + 1% Hasten 500 A-DIM 0 S

Hussar + 1% Hasten 200 B-SU 90 RRR

Atrazine + 0.2% BS1000 2000 C 0 S

Triflur X 1000 D 0 S

What’s the outcome if farmer had chosen Verdict?

Q. Will Axial/ Achieve work??

Results Ratings

RRRRR

R

Quick-Test: Monitoring: identify survivors

Why has this individual survived and the others haven't?

Is it resistant?

Post Plants

Growth stage = 1-2 leaf to advanced tillering

Best stage is early tillering

Rinse soil off roots

Plants can be trimmed

Leaves dry

Add NO water

Quick-Test: collect plants

Make cuttings

Cuttings and re-growth

1. Cuttings2. Regrowth 5-10 days later3. Spray

Compared to Standard Resistant and Susceptible biotypes in every test

Assess 2-3 weeks after spray

Test for any post emergence herbicide

CROP SEED QALITY TESTING Crop Seed Quality Testing

Why test crop seed?

Maximise crop establishment & competition with weeds

Germination- establishment under good conditions

Vigor- establishment under sub-optimal conditions/ heavy weed burdens

Seed weight accurate seeding rates/ good vigour

Crop Seed Quality Testing

For more information


Successful weed control = integrated weed management

1. Effective herbicides• Knockdown• Pre-emergence• Post-emergence• Seed-set stage

2. Non-herbicide strategies

3. Resistance testing

“when on a good thing don’t stick to it!!

IWM Crop Competition tactics

• Crop competition- barley-oats-trit-wheat-durum• Crop choice- cereals vs broadleaf crops• Seeding rate/ Crop density• Row Spacing• Cultivar choice• Optimum planting time• Seeding depth• Seed vigor (Quality testing)• Fertilizer timing• Pest and disease management

Seedbanks- the seed in your paddock

• Surviving weeds set seed• Low numbers of resistant weeds can set lots of

seeds• Seed longevity

– Differs between species– Left on surface vs burial (tillage systems)

Managing the Weed Seed Bank

1993 1994 1995 1996 1997 1998 19990

2000

4000

6000

8000

10000

12000

14000

16000

18000Beans Wheat Pasture Pasture Pasture Canola

2 CultivationsTrifluralin

Diclofop-methylCultivationGlyphosateTrifluralinClethodim

Haloxyfop-ethylWindrow

Mechanicaltop

Mechanicaltop

Mechanicaltop

Spraytop

Year

An

nu

al r

yeg

rass

(se

ed m

-2)

Successful farmers stop weed seed-set

Non-herbicide– Green manure– Hay, Silage– Competitive crops– Chaff cart– Harrington Seed Destructor– Burning stubbles/ wind rows

Herbicide– Brown manure– Crop topping – Pasture topping– Wick-wiping (lentils)

Burning Header Rows

The End


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