Weed Resistance Management in the Southern SJVresistance in the field? Kurt Hembree – March 11,...

Kurt Hembree – March 11, 2015

PAPA Seminar

March 11, 2015

Kurt Hembree

Weed Management Farm Advisor, Fresno County

Weed Resistance

Management in the

Southern SJV

“Diversity and proactive

weed management is the

only way farmers are going

to survive this thing –

herbicide resistance.” From the Global Herbicide Resistance Challenge Conference, 2013



http://www.google.com/url?sa=i&rct=j&q=funny weed management&source=images&cd=&cad=rja&docid=wrlbq9giRKAEkM&tbnid=-6YoA7846VmExM:&ved=0CAUQjRw&url=http://www.agweb.com/blog/Rubes_Cartoons_-_Tales_from_a_Twisted_Mind_263/?Year=2010&Month=3&ei=Job5UbanF4eGiQK0moDQCg&psig=AFQjCNFuLuzxUy6dy-21XrLrp-BYvDWNbQ&ust=1375393607109386


http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=qmgLEvrbNmRsxM&tbnid=gD7aU6fPU1-v_M:&ved=0CAUQjRw&url=http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=3708&ei=4EgeUq3qJ-GligL-1YHIAw&bvm=bv.51495398,d.cGE&psig=AFQjCNEXVl8fERHDXkLap0AROc8TsO0YgA&ust=1377802675964134

Resistance vs. Tolerance:

Resistance: “The inherent ability of a weed to survive and

reproduce following exposure to a dose of herbicide

normally lethal to the wild type”. (WSSA)

The herbicide once worked at label rates, but now it doesn’t.

Tolerance:

“The inherent ability of a weed to withstand the specific

effects of a particular herbicide”. (WSSA)

The herbicide never really worked brfore.


How selection for resistance occurs:


► Altered target site

► Enhanced metabolism

► Compartmentalization or sequestration

► Overexpression of target protein

► Altered translocation

► Gene amplification

Mechanisms of resistance:

Target site is no

longer susceptible

to the herbicide.


Glyphosate-resistant fleabane Glyphosate-resistant ryegrass

Glyphosate-resistant junglerice


Weed biotype - CA Situation Herbicide family Year

Common groundsel Asparagus PS II 1981

Perennial ryegrass RR, Roadside ALS 1989

Smallflower umbrella sedge Rice ALS 1993

California arrowhead Rice ALS 1993

Russian thistle Roadside ALS 1994

Wild oat Barley, Wheat Pyrazoliums 1996

Redstem Rice ALS 1997

Ricefield bulrush Rice ALS 1997

Late watergrass Rice ACCase and Lipid syn. 1998

Rigid ryegrass Almond Glycine (glyphosate) 1998

Long-leaved loosestrife Rice ALS 2000

Barnyardgrass Rice ACCase and Lipid syn. 2000

Early watergrass Rice ACCase and Lipid syn. 2000

Littleseed canarygrass Onion ACCase 2001

Smooth crabgrass Rice Synthetic Auxins 2002

Horseweed T&V, Roadside Glycine (glyphosate) 2005

Hairy fleabane T&V, Roadside Glycine (glyphosate) 2007

Hairy fleabane T&V, Roadside Glycine (glyphosate) and Bipyridiliums (paraquat) 2009

Junglerice Corn, Alfalfa, T&V, Roadside Glycine (glyphosate) 2011


Other weeds to watch out for:

► Palmer amaranth, Lambsquarters, (glyphosate)

► Junglerice, Barnyardgrass, Sprangletop (DNAs)

Palmer amaranth

Lambsquarters Sprangletop

Barnyardgrass


http://www.weedscience.com


How do you recognize herbicide

resistance in the field?


If you have trouble controlling a specific

weed with a specific labeled herbicide a.i.

and/or are having to use higher and

higher rates of that a.i. to control a

particular weed, and you’ve ruled out any

errors associated with timing and

application, you may have resistance.

A Reality Check:

Some weeds can spread a long distance, so

resistant weeds may pop-up in your field by nothing

you’ve done, but it still has to be dealt with!


Maybe it’s time to try

something different?



http://www.google.com/url?sa=i&rct=j&q=change ahead&source=images&cd=&cad=rja&docid=yAzW3YJH9sZrUM&tbnid=VW3y8riIJ8A51M:&ved=0CAUQjRw&url=http://godwillbegod.com/blog/tag/bruce-sanguin&ei=u4T5UcCXOofpigKVtoCoDg&bvm=bv.50165853,d.cGE&psig=AFQjCNHwycqg0g32N6vafQd8M1WTJU5Iew&ust=1375392910570283

Strategies for proactive

weed management:

“Keeping weeds susceptible”

“4-step program”


Weed Seeds/plant

Horseweed/Marestail 1,000,000

Large crabgrass 150,000

Common lambsquarters 72,450

Common purslane 52,300

Barnyardgrass 40,000

Shepherd’s-purse 38,500

Prickly lettuce 27,900

Hairy fleabane 10,000

Yellow foxtail 6,420

Wild oats 250

1. Don’t add to the seed bank:


Follow-up control of weed escapes,

including borders, edges, and ditches:


2. Have a good spray operation:

► Sprayer performance

► Spray tip performance

► Rate(s) used

► Weather conditions

► Spray coverage issues

► Treatment timing

► Applicator skill and attitude


3. Refer to the label for help:


4. Diversify the control tactics: Control tactic Potential impact

Herbicide – rotation (MOAs) Excellent

Herbicide – mixtures (MOAs) Excellent

Herbicide – timing Excellent

Herbicide – rate Fair

Herbicide – precision application Poor

Tillage – primary Good to Excellent

Tillage – general mechanical Fair to Good

Cultural – crop selection/rotation Fair to Good

Cultural – planting date Poor to Fair

Cultural – seeding rate Fair

Cultural – planting configuration Good

Cultural – cover crops, mulching Poor


PRE + POST

POST



PRE + POST POST

0

10

20

30

40

50

9 14 10 22 3 4 5 2 1 7 12 8 21 15 17 29

Acre

s t

reate

d (

%)

WSSA MOA group number

Herbicide use in trees and vines in CA in 2010 (tree nuts, grapes, and stone fruits)

Source: CA DPR

glufosinate

paraquat

oxyfluorfen, flumioxazin,

carfentrazone, pyraflufen

glyphosate

80%


0

10

20

30

40

50

9 7 14 3 1 2 15 5 10 17 met

Acre

age t

reate

d (

%)

WSSA MOA group number

Herbicide use in cotton in CA in 2011

Source: CA DPR

diuron

glyphosate

pendimethalin,

trifluralin

oxyfluorfen, flumioxazin

90%


In almonds for example:

Preemergent

MOA

(group #)

Postemergent

MOA

(group #)

Matrix 2 Selectmax, Fusilade, Poast 1

Surflan, Prowl, Treflan 3 2,4-D 4

Princep 5 Roundup (others with glyphosate) 9

Eptam 8 Rely 280, Cheetah, Lifeline, etc. 10

Solicam 12 Shark, Goal, Venue, Chateau, Treevix 14

Chateau, Goal 14 MSMA 17

Trellis 21 Gramoxone Inteon 22

Alion 29

Pindar GT 2 + 14

Rotate and/or tank-mix

herbicides with different MOAs:



Untreated

Roundup (9)

Treevix (14) + Roundup (9)

Untreated Roundup (9) – 30 DAT

Roundup (9) + Chateau (14) – 30 DAT Rely 290 (10) + Chateau (14) – 30 DAT


0

2

4

6

8

10

RU GR RL TV SK VU RU +VU

RU +TV

RU +CH

RU +SK

RL +SK

RL +RU

RL +VU

Contr

ol

Postemergence control of horseweed and hairy fleabane

Horseweed Fleabane


Grape trial 2014 (90 DAT) Untreated Mission (2) + RU (9)

+ AMS + MSO

Mission (2) + Chateau (14) + RU (9)

+ AMS + MSO

Mission (2) + Alion (29) + RU (9)

+ AMS + MSO


Glyphosate-resistant junglerice control:

T. Lanini, UC Davis


http://ucipm.ucdavis.edu


http://cefresno.ucdavis.edu


US CA

Cotton – 90% Cotton – 85%

Corn – 80% Corn – 60%

Soybean – 80% Soybean – NA

Alfalfa – 5% Alfalfa – <10%


Roundup Ready system concerns:

Weed shifts occur fairly quickly if we rely

on the same herbicide MOA year-after-year:

M. Canevari


Pre-Roundup Ready Cotton…

• Weed control was based on:

– “yellow” herbicides PPI

– PRE herbicides at-planting

– POST-DIR at 3- to 4-inch cotton

– 3-4 Cultivations

– Non-selective herbicides under hoods

– Layby residual treatment

– Spot spraying

– Weeding by hoe crews

– Staple POST OTT in 1996

S. Wright


Roundup Ready Cotton…

• Weed control is based on:

– “yellow” herbicides PPI or PRE ?

– Glyphosate OTT cotton (1-3X)

– Glyphosate POST-DIR (alone or with residuals)

S. Wright


Vary the control tactics where practical:


Make sure your treatment timing is

the same as the label’s timing:


Horseweed control across postemergence herbicides tested

Parlier 2006

0

2

4

6

8

10

2-14 leaf Rosette 6-12" bolted

Horseweed growth stage

Co

ntr

ol


Liberty Timing/Rate -- Palmer amaranth

0

10

20

30

40

50

60

70

80

90

100

2 4 6 8 10 12 unt.

Weed Height (inches)

We

ed

Co

ntr

ol (p

erc

en

t)

0.42 lb ai/A -- 7 DAT

0.42 lb ai/A -- 14 DAT

0.52 lb ai/A -- 7 DAT

0.52 lb ai/A -- 14 DAT

S. Wright and R. Vargas


4TL, 1” or less >5 TL and >1”


S. Wright and R. Vargas

Take-home points when considering

weed resistance management:

► Be proactive by keeping weeds susceptible, which includes

making changes to the program as needed.

► Have a strategy (“4-step program”)

1. Do what you can to prevent weeds from going to seed.

2. Make sure the spray operation is up to par.

3. Refer to the label for helpful guidelines.

4. Diversify efforts (MOAs, treatment timing, cultivation, etc.).


“Improvise, Adapt, Overcome” Clint Eastwood – Heartbreak Ridge


Weed Resistance Management in the Southern SJVresistance in the field? Kurt Hembree – March 11,...

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