Weed Control in Pulses Maximizing Your Options CropSphere Jan. 11, 2017

Transcription

1 Weed Control in Pulses Maximizing Your Options CropSphere Jan. 11, 2017 Eric Johnson, Chris Willenborg, Lena Syrovey and Steve Shirtliffe. University of Saskatchewan; Glenda Clezy, Saskatchewan Pulse Growers

2 Outline Update on herbicides for pulses Soybeans weed control options Alternatives to herbicides?

3 Group 2 (ALS resistant weeds in Canada) Broadleaf Weeds Cleavers (A,M,S) Stinkweed (A,M,S) Kochia (A,M,S) Wild mustard (A,S) Shepherd s purse (A,S) Wild buckwheat (A) Narrow-leaved hawksbeard (A) Spiny Annual Sow-thistle (A) Chickweed (A,M,S) Russian thistle (A,S) Hemp nettle (A,M,S) Redroot pigweed (M,S,O) Cow-cockle (A) Pale smartweed (A,M) Lambsquarters (O) Powell Amaranth (O) Eastern black nightshade (O) Ragweed (O) Waterhemp (O) Canada fleabane (O) A=Alberta, M=Manitoba, O=Ontario, S=Saskatchewan

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5 New herbicide Mode of Action Only about 3 to 4 new a.i. s to be introduced until 2020, all from existing classes. Latest cost to develop new herbicide is about $286 Million (regulatory costs rising) About 1 in 140,000 products screened make it to market. Some estimates that earliest a new mode of action will be available is If so, it will target: Corn, soybean, rice, cotton, and/or maybe wheat!

6 Frequency of Resistant Individuals (%) Herbicide A or B used alone Herbicide A and B rotated Tank-mix of Herbicide A and B Generations

7 Herbicide Layering Using both pre- and post-emergent herbicides of different modes of action to reduce risk of weed resistance and improve overall weed control. Pre- is a short or medium-term residual product Concept is to reduce weed population for in-crop application. Resistance is a numbers game, reduce the numbers, reduce selection pressure. Ideal is to use different herbicide groups, 3 to 4 MOA in the crop

8 Herbicide Layering Should be viewed as another tool, not a solution. At some point, we must stop looking to herbicides as the solution to a problem created by herbicides Dr. Andrew Kniss University of Wyoming

9 Layering Options for Group 2 R cleavers *Necessary in high organic matter soils PRE Field pea Edge (fall applied, helps to incorporate with heavy harrow), Authority, Heat, Command*, Focus* Lentil Edge (same as above), Heat, Focus*. POST Field pea Viper, Basagran Lentil nothing *Not yet registered

10 Group 2 Resistant cleavers control Average of 3 Years ( ). SOM > 6%. Melfort (2013), Rosthern ( )

11 Group 2 Resistant cleavers control Average of 2 Years ( ). SOM > 6%. Rosthern, SK.

12 Potential Layering Options for Group 2 R kochia in Pulses PRE Field pea Edge (fall applied, helps to incorporate with heavy harrow), Authority, Heat Lentil Edge (same as above), Heat, Fall applied Valtera*, Focus* POST Field pea Viper, Basagran Lentil nothing

13 Fall applied Valterra Weed Control Saskatoon and Scott, Numbers above bars indicate # of site-years

14 Potential (?) layering options for Gr 2 R stinkweed in pulses PRE Peas Focus*, Heat, Valtera Lentil Focus*, Heat, Fall applied Valtera* (?) POST Peas Viper, Basagran, Sencor Lentil Sencor *Not yet registered Speculative as I have not done any research on this!

15 Soybean Acres Soybean Seeded Acres (Stats Can) Ontario Manitoba Quebec Saskatchewan Maritimes

16 Important Weeds to Consider Broadleaf Volunteer Canola Wild Buckwheat Redroot Pigweed Thistle Kochia Lamb s-quarters Stinkweed Narrow-leaved Hawksbeard Round-leaved Mallow Dandelion Grass Green Foxtail Wild Oat Barnyard Grass Foxtail Barley Photo Courtesy of Dennis Lange Manitoba Agriculture

17 Why Early Weed Control? Soil warming / Seedbed Crop Emergence Small Weeds Herbicide Efficacy

18 Critical Weed Free Period

19 Yield Loss Due To Weeds Sikkema, UG Dry Bean Corn Soybean Spring Cereals 12 3 Winter Wheat Ridgetown & Exeter, ON ( ) Field Studies

20 Impact of Weeds on Soybean Yield Greg Endres, 8 site-years ( ), North Dakota

21 Soybean Herbicide Traits

22 Current Herbicide Options Pre-Seed / Pre-Emergent Aim / CleanStart (carfentrazone) 14 Authority / Authority Charge (sulfentrazone / +carfentrazone) Group 14 Blackhawk TM (carfentrazone + 2,4-D) 14+4 Edge TM Granular (ethafluralin) 3 Express SG (tribenuron) 2 Focus (carfentrazone + pyroxasulfone) Heat (saflufenacil) 14 Reflex / Flexstar (fomasafen) 14** Valtera TM (flumioxazin) D 4 **Fomasafen is for use in Manitoba Red River Valley Only In-Crop Basagran / Basagran Forte (Bentazon) Blazer (acifluorfen) 14 Odyssey / Odyssey Ultra (imazamox + imazethapyr / +sethodxydim) Pinnacle SG (thifensulfuron methyl) 2 Solo ADV (imazamox) 2 Group 6 2 / 2+1 Viper ADV (imazamox +bentazon) 2+6 Reflex / Flexstar (fomasafen) 14** Quizalofop, sethoxydim, clethodim 1

23 Effect of Pre-Post Combinations on Volunteer RR Canola Biomass Mierau, M.Sc. Thesis Glyphosate Check 1548 kg /ha.

24 Effect of Pre-Post Combinations on Soybean Yield Mierau, M.Sc. Thesis ABC ABCD A ABC ABC ABC D CD ABCD BCD

25 PRE-SEED 2,4-D INJURY TO SOYBEAN

26 Volunteer Canola Action Thresholds Paul Gregoire & Dr. R. Gulden, University of Manitoba 0 seeds m seeds m seeds m seeds m seeds m seeds m seeds m seeds m -2

27 Impact of Row Spacing Photo Courtesy of University of Illinois

28 Seeding Rate Mierau M.Sc. Project

29 Seeding Date Earlier? Weed competition Environmental conditions Maturity

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32 Wicking / Weed Wiping in Lentil

33 WM Seed Production (/5 plants) Wild Mustard Seed Yield 3 site-yrs a Herbicide P = b b b ,4-D Amine Control Dicamba Glyphosate

34 WM Seed Production (Prop of Control) WM Seed Production (Prop of Control) Wild Mustard Seed Yield - Timing N 2,4-D Amine Dicamba Week of Application Week of Application

35 2015 Wild Mustard Seed Production Untreated Taken 1 month after application Photos: H.S.N. Duddu Glyphosate Wk 1

36 Lentil Yield (kg ha-1) Lentil Yield ,4-D Amine Control Dicamba Glyphosate b a a a a a c b b b bc a N 2016S

37 Effect of lentil desiccants on Kochia seed production (% reduction). Mean of 4 siteyears. E. Bertholet M.Sc. Project. Not as effective on mustard seed reduction

38 Conclusions Herbicides are an option, but not the only one As resistance increases, weed control in pulses will become more complex Lengthening crop rotations will be critical to long term weed management