weed resistance and management options - vineyard teamweed biotype - ca situation herbicide family...

Kurt Hembree – Nov 16, 2015

Sustainable Ag ExpoNov 16, 2015

Kurt HembreeWeed Management Farm Advisor, UCCE, Fresno County

cefresno.ucanr.edu

Weed Resistance and Management OptionsWeed Resistance and Management Options

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 before.


Cross-resistance: possess one mechanism that can withstand herbicides from different chemical families.

- A single point mutation in the enzyme acetolactate synthase(ALS) may provide resistance to the sulfonylurea and imidazolinone herbicide families.

Types of resistance:


Multiple-resistance: possess more than one mechanism that can withstand herbicides from different chemical families.

- In this case, herbicide options become very limited. Kochiascoparia population identified with target-site resistance to the PS II inhibitor herbicide, triazine, and to ALS inhibitor herbicides. Hairy fleabane in CA resistant to paraquat and glyphosate.

► 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.


How selection for resistance occurs:


Weed biotype - CA Situation Herbicide family YearCommon 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 escaping glyphosate:

Palmer amaranth

Sprangletop

Lambsquarters


How do you recognize if herbicide resistance may be occurring? Label followed (rate, timing, additives, etc.);

Loss of effectiveness at label rates observed over time;

Small patches of escaped plants;

Spray application done properly (coverage, gpa, calibration, etc.).


A Reality Check:

Some weeds can spread a long distance, so resistant weeds may pop-up in your field even if you

are on top of your weed game!


Maybe it’s time to try something different?


Strategies for proactiveweed management:

“Keep the weeds susceptible”

“Develop a plan and be willing to make changes as needed”


1. Don’t add to the seed bank:Weed Seeds/plant

Horseweed/Marestail 1,000,000Large crabgrass 150,000Common lambsquarters 72,450Common purslane 52,300Barnyardgrass 40,000Shepherd’s-purse 38,500Prickly lettuce 27,900Hairy fleabane 10,000Yellow foxtail 6,420Wild oats 250


Follow-up with control of weed escapes, including borders, edges, and ditches:


2. Have a good spray operation:

► Sprayer performance

► Spray tip performance

► Rate(s) used

► Weed susceptibility

► Spray coverage issues

► Treatment timing

► Applicator skill and attitude


3. Refer to the label for guidance:


4. Diversify the control tactics:

Control tactic Potential impactHerbicide – rotation (MOA) ExcellentHerbicide – mixtures (MOA) ExcellentHerbicide – timing ExcellentHerbicide – uniformly applied Good to ExcellentHerbicide – rate GoodMechanical – primary Fair to GoodCultural – irrigation type Fair to GoodCultural – cover crops, mulching Poor to Fair


PRE + POSTPOST


0

10

20

30

40

50

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

Acr

es tr

eate

d (%

)

WSSA MOA group number

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

Source: CA DPR

oxyfluorfen, flumioxazin,carfentrazone, pyraflufen

glyphosate

65%



0

10

20

30

40

50

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

% of total acres treated

Herbicide MOA Group Number (WSSA)

Herbicides applied to wine grapes in 2013

SLO FCSource: CA DPR

65%

oxyfluorfen, flumioxazin,carfentrazone, pyraflufen

glyphosate

MOA Herbicide mode of action Herbicide Product Activity1 Acetyl CoA carboxylase Select, Poast, Fusilade POST

2 Acetolactate synthase Matrix, Mission, Pindar GT (+14) PRE & POST

3 Microtubule assembly Surflan, Prowl, Treflan PRE

4 Synthetic auxin 2,4-D POST

5 Photosystem II Hyvar, Princep PRE

7 Photosystem II Direx PRE

8 Lipid synthesis EPTC PRE

9 EPSP synthase Roundup, etc POST

10 Glutamine synthase Rely 280, Lifeline, etc. POST

12 Carotenoid biosynthesis Solicam PRE

14 Protoporphyrinogen oxidase Chateau, GoalShark, Venue, Treevix

PRE & POSTPOST

15 Cell division Devrinol PRE

21 Cellulose biosynthesis Trellis PRE

22 Photosystem-I-electron diversion Gramoxone POST

27 Hydroxyphenylpyruvate dioxygenase Broadworks PRE & POST

29 Cellulose biosynthesis Alion PRE

Rotate and/or tank-mix MOAs (TNV)


Untreated Roundup (9) – 30 DAT

Roundup (9) + Rely 280 (10) – 30 DAT Rely 290 (10) + Chateau (14) – 30 DAT


Untreated Mission (2) + RU (9)+ AMS + MSO

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

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


T. Lanini, UC Davis

UNT

Broadworks (27)+ Prowl H2O (3)

Broadworks (27)+ Alion (29)

Broadworks (27)+ GoalTender (14)


http://ucipm.ucdavis.edu



cefresno.ucanr.edu

Horseweed control across postemergence herbicides tested Parlier 2006

0

2

4

6

8

10

2-14 leaf Rosette 6-12" bolted

Horseweed growth stage

Con

trol



“In-row mowing” “In-row tilling”

“In-row disking” “In-row plowing”


French Plow Bezzerides

Steam Greenmatch

Dr. Anil Shrestha, Fresno State

Take-home points when considering weed resistance management:

► Be proactive by keeping weeds susceptible.

► Develop a plan and be willing to modify it as needed: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 and management options - vineyard teamweed biotype - ca situation herbicide family...

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