Weed Resistance Management in the Southern SJV

Transcription

1 Weed Resistance Management in the Southern SJV PAPA Seminar March 11, 2015 Kurt Hembree Weed Management Farm Advisor, Fresno County

2 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

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5 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.

6 How selection for resistance occurs:

7 Mechanisms of resistance: Altered target site Enhanced metabolism Compartmentalization or sequestration Overexpression of target protein Altered translocation Gene amplification Target site is no longer susceptible to the herbicide.

8 Glyphosate-resistant fleabane Glyphosate-resistant ryegrass Glyphosate-resistant junglerice

9 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 Rigid ryegrass Almond Glycine (glyphosate) 1998 Long-leaved loosestrife Rice ALS 2000 Barnyardgrass Rice ACCase and Lipid syn Early watergrass Rice ACCase and Lipid syn 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

10 Other weeds to watch out for: Palmer amaranth, Lambsquarters, (glyphosate) Junglerice, Barnyardgrass, Sprangletop (DNAs) Palmer amaranth Barnyardgrass Lambsquarters Sprangletop

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12 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.

13 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!

14 Maybe it s time to try something different?

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16 Strategies for proactive weed management: Keeping weeds susceptible 4-step program

17 1. Don t add to the seed bank: 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

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

19 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

20 3. Refer to the label for help:

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22 4. Diversify the control tactics: Control tactic Herbicide rotation (MOAs) Herbicide mixtures (MOAs) Herbicide timing Herbicide rate Herbicide precision application Tillage primary Tillage general mechanical Cultural crop selection/rotation Cultural planting date Cultural seeding rate Cultural planting configuration Cultural cover crops, mulching Potential impact Excellent Excellent Excellent Fair Poor Good to Excellent Fair to Good Fair to Good Poor to Fair Fair Good Poor

23 POST PRE + POST

24 POST PRE + POST

25 Acres treated (%) 50 Herbicide use in trees and vines in CA in 2010 (tree nuts, grapes, and stone fruits) 40 glyphosate oxyfluorfen, flumioxazin, carfentrazone, pyraflufen 80% 10 glufosinate paraquat WSSA MOA group number Source: CA DPR

26 Acreage treated (%) 50 Herbicide use in cotton in CA in 2011 glyphosate diuron oxyfluorfen, flumioxazin pendimethalin, trifluralin 90% met WSSA MOA group number Source: CA DPR

27 Rotate and/or tank-mix herbicides with different MOAs: In almonds for example: MOA MOA Preemergent (group #) Postemergent (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

28 Untreated Treevix (14) + Roundup (9) Roundup (9)

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

30 Control Postemergence control of horseweed and hairy fleabane RU GR RL TV SK VU RU + VU RU + TV RU + CH RU + SK RL + SK RL + RU RL + VU Horseweed Fleabane

31 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

32 Glyphosate-resistant junglerice control: T. Lanini, UC Davis

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35 Roundup Ready system concerns: US CA Cotton 90% Cotton 85% Corn 80% Corn 60% Soybean 80% Soybean NA Alfalfa 5% Alfalfa <10%

36 Weed shifts occur fairly quickly if we rely on the same herbicide MOA year-after-year: M. Canevari

37 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

38 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

39 Vary the control tactics where practical:

40 Make sure your treatment timing is the same as the label s timing:

41 Control Horseweed control across postemergence herbicides tested Parlier leaf Rosette 6-12" bolted Horseweed growth stage

42 Weed Control (percent) Liberty Timing/Rate -- Palmer amaranth unt. Weed Height (inches) 0.42 lb ai/a -- 7 DAT 0.42 lb ai/a DAT 0.52 lb ai/a -- 7 DAT 0.52 lb ai/a DAT S. Wright and R. Vargas

43 4TL, 1 or less >5 TL and >1 S. Wright and R. Vargas

44 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.).

45 Improvise, Adapt, Overcome Clint Eastwood Heartbreak Ridge