Herbicides in Rotation with Corn

Transcription

1 Herbicides in Rotation with Corn Tom Peters Extension Sugarbeet Agronomist North Dakota State University and the University of Minnesota

2 Only 1200 days until planting; planning your weed control program for 2020

3 Weed Management is a Strategy Identify problem weeds and develop a multi-year plan for their control Scout fields Positive identification of weeds Weed maps in fields Plan crop sequences in fields Carefully plan your choice of herbicides, herbicide families Observe and adjust

4 Three important weeds kochia common ragweed waterhemp

5 Weed Biology Common ragweed Germinates between soil temperature 50 and 80 F, returns to dormancy when it gets hot 25 to 35 years seed viability Common in soybean or dry bean rotation Kochia Very deep rooted, tolerate saline soils Extremely competitive; a few plants will reduce yield Seed viability, 1 to 2 years Waterhemp Germinates and emergence mid to late May through August Dioecious, tremendous diversity, herbicide resistant Seed viability is 4-6 years, but rapidly declines over years

6 Common lambsquarters Horseweed Biennial wormwood Volunteer canola Redroot pigweed Volunteer corn There are other weeds

7 On your farm / in your field Rank troublesome weeds in each field on the farm Crops to be planted will determine herbicide choices Select crops based on effective herbicides against target weeds Be creative Weed biology Mechanical and cultural practices compliment herbicides Rotate herbicides Decide where you absolutely must have glyphosate Save glyphosate for sugarbeet

8 Evans, Tranel, Hager, et al., University of Illinois Herbicide mixing, is the most effective tool in managing resistance Resistant waterhemp was greatest in fields where: glyphosate was used more than 75 percent of the seasons where fewer modes of action were used each year where herbicide rotation occurred Rotating herbicides only delays the onset of resistance Tank-mixes were least likely to contribute to resistance At least two herbicides with different SOA, effective against target weeds in field Jeffrey A Evans, Patrick J Tranel, Aaron G Hager, Brian Schutte, Chenxi Wu, Laura A Chatham and Adam S Davis. January, Managing the evolution of herbicide resistance. Pest Management Science. Volume 72, Issue 1, pages

9 Purpose of my presentation Review herbicide (SOA) Site of Action Why is it important? How does it impact my choice of herbicides? How does it impact my crop rotations? What is meant by effective herbicides

10 What is herbicide Site of Action (SOA)? What is the difference between SOA and herbicide Mode of Action? Site of Action (SOA) The specific process disrupted by herbicide to kill weeds Where herbicides works, e.g. destroys chlorophyll by blocking enzymes at specific place, specific site SOA named after the protein herbicide inhibits Mode of Action (MOA) The way in which herbicide acts to kill weeds Series of steps - absorption and movement into the plant, and plant injury symptoms How herbicide works, e.g. destroys chlorophyll

11 Herbicide Site of Action / Effective herbicides A numbering system developed to evaluate a herbicide program Each SOA is assigned a group number Group number found on the first page of herbicide labels Herbicide in the mix must be effective alone on the target weed A herbicide is considered effective if it is highly active against target weed Can t obtain a lethal dose by combining sub-lethal doses of the individual herbicides

12 Group number, site of action, and trade name Group 1 ACC-ase enzyme Discover, Select Max, Axial XL 2 ALS enzyme Express, Harmony, Raptor 3 Microtubule inhibitors Prowl, Sonalan, Treflan 4 IAA like 2,4-D, Banvel, Starane 5 PS II mobile atrazine, Metribuzin 6 PS II contact Basagran 9 EPSP enzyme Roundup/glyphosate 10 GS enzyme Liberty 14 PPO enzyme Spartan, Sharpen, Flexstar 15 Cell division inhibitors Harness/Surpass, Zidua 22 PS I enzyme Paraquat, Diquat 27 HPPD enzyme Callisto, Impact, Laudis

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14 Group 1 (ACC-ase Enzyme Inhibitor) Herbicides Discover or Assure II ( fop ), Select ( dim ), Axial ( den ) Key plant symptoms: active on grass weeds translocating herbicide moves to the meristem growing point chlorotic/death inner whorl easily pulled from plant Slides and ideas adapted from presentations by Greg Endres and Brian Jenks

15 Axial XL on wild oat

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17 Group 14 [PPO (Protox) Enzyme Inhibitor] Herbicides Cobra and Flexstar (diphenylether), Sharpen, (pyrimidinedione) Spartan (triazolinone) Key plant symptoms: mostly active against broadleaf weeds contact herbicides older leaves injured, new growth not affected destroy plant cell membranes causing rapid tissue necrosis

18 Cobra on soybean Greg Endres, NDSU

19 Its your turn Remember the rules- Continued use of the same postemergence herbicide/same SOA causes weed resistance Herbicide rotation delays resistance but does not stop resistance Herbicide rotation and mixtures are the most durable approach

20 Rotating herbicides for wild oat and redroot pigweed control Year Crop Herbicide Group Num 2017 RR Corn PowerMax RR Soybean PowerMax RR Corn PowerMax RR Soybean PowerMax RR Corn PowerMax RR Soybean PowerMax RR Corn PowerMax RR Soybean PowerMax RR Corn PowerMax RR Soybean PowerMax RR Corn PowerMax 9 Very Risky

21 Rotating wheat herbicides for wild oat control Year Crop Herbicide Group Num 2017 Wheat GoldSky RR Soybean PowerMax Wheat GoldSky RR Soybean PowerMax Wheat GoldSky RR Soybean PowerMax Wheat GoldSky RR Soybean PowerMax Wheat GoldSky RR Soybean PowerMax Wheat GoldSky 2 Rotating yes, but Risky

22 Rotating wheat herbicides for grass control Year Crop Herbicide Group Num 2017 Wheat Axial XL 1 (den) 2018 RR Soybean PowerMax Wheat GoldSky RR Soybean PowerMax Wheat Puma 1 (fop) 2022 RR Soybean PowerMax Wheat Huskie Complete RR Soybean PowerMax Wheat Axial XL 1 (den) 2026 RR Soybean PowerMax Wheat Varro 2 Better, But still Risky

23 Rotating wheat herbicides for grass control Year Crop Herbicide Group Num 2017 Wheat Axial XL 1 (den) 2018 Lentil Sonalan / Assure II 3 / 1 (fop) 2019 Wheat GoldSky RR Soybean Fierce / PowerMax 15 / Wheat Puma 1 (fop) 2022 Dry pea BroadAxe / Select 15 / 1 (dim) 2023 Wheat Huskie Complete RR Canola PowerMax Wheat Axial XL 1 (den) 2026 LL Canola Liberty + Select (dim) 2027 Wheat Varro 2 Now you got it!

24 There are many factors in addition to resistance management as you select herbicides Herbicide efficacy Crop rotation restrictions Herbicide costs Sprayer cleanout Other weeds in field Other weed control methods Others

25 Three bad actors kochia common ragweed waterhemp

26 Waterhemp control in soybean Group 2 ALS Harmony, FirstRate, Raptor 3 DNA Prowl, Sonalan, Treflan 4 Gro Regulators 2,4-D, Banvel 5 PSII-mobile Metribuzin 6 PSII-Contact Basagran 9 EPSP PowerMax/glyphosate 10 N inhibitors Liberty 14 PPO inhibitors Spartan, Sharpen, Flexstar 15 Acetamides Harness/Surpass, Zidua 27 HPPD Future 31 Ferrous oxide

27 Waterhemp control in soybean What s left? - Yellow herbicides Prowl / Treflan / Sonalan - Engenia or XtendiMax DT soybean seed - Metribuzin <7.5 soil ph - Basagran + MSO adjuvant - <2 inch - Liberty LibertyLink seed - Residual PRE Outlook, Warrant, Zidua - PPO inhibitors PRE Spartan, Sharpen POST Reflex, Flexstar - Ferrous oxide Cold Hard Steel

28 Kochia control in soybean Group 2 ALS Harmony, FirstRate, Raptor 3 DNA Prowl, Sonalan, Treflan 4 Gro Regulators 2,4-D, Banvel 5 PSII-mobile Metribuzin 6 PSII-contact Basagran 9 EPSP PowerMax/glyphosate 10 N inhibitors Liberty 14 PPO inhibitors Spartan, Sharpen, Flexstar 15 Acetamides Harness/Surpass, Zidua 27 HPPD Future 31 Ferrous oxide

29 Kochia control in soybean What s left? - Engenia or XtendiMax DT seed - Metribuzin <7.5 soil ph - Basagran + MSO adjuvant - <2 inch - Liberty LibertyLink seed - PPO inhibitors PRE Spartan, Sharpen POST Reflex, Flexstar - Ferrous oxide Cold Hard Steel

30 Common ragweed control in soybean Group 2 ALS Harmony, FirstRate, Raptor 3 DNA Prowl, Sonalan, Treflan 4 Gro Regulators 2,4-D, Banvel 5 PSII-mobile Metribuzin 6 PSII-Contact Basagran 9 EPSP PowerMax/glyphosate 10 N inhibitors Liberty 14 PPO inhibitors Spartan, Sharpen, Flexstar 15 Acetamides Harness/Surpass, Zidua 27 HPPD Future 31 Ferrous oxide

31 Common ragweed control in soybean What s left? - Engenia or XtendiMax DT soybean - Metribuzin <7.5 soil ph - Liberty LibertyLink soybean - PPO inhibitors PRE Spartan, Sharpen POST Reflex, Flexstar - Ferrous oxide Cold Hard Steel

32 Conundrum Ragweed Waterhemp Kochia - - DNA (yellow) - - Sharpen - Sharpen - Sharpen - - Spartan - Spartan - - Valor - Valor (S) - Metribuzin - Metribuzin - Metribuzin - - Zidua - Zidua (S) - - Basagran - Basagran - Cobra - Cobra - - Flexstar - Flexstar - Flexstar - Liberty - Liberty - Liberty - DT soybean - DT Soybean - DT Soybean - Cold hard steel - Cold hard steel - Cold hard steel Too much PPO inhibitor herbicides, group number 14! Alicia Harstad, NDSU

33 PPO Herbicides (SOA 14) across crops Soybean Sharpen, Valor, Cobra, Flexstar Small grains Athem Flex, Aim Preharvest Sharpen Corn Sharpen, Valor Sugarbeet Dry beans Spartan Elite, Spartan Charge Sharpen, Valor

34 Growth regulators (SOA 4) across crops Soybean Enlist, Xtendimax with VaporGrip, Engenia Small grains MCPA, dicamba, Curtail, PerfectMatch, Starane Flex, Supremacy, Travallas, Axial Sar, Raze, Goldsky Preharvest 2,4-D, dicamba Corn dicamba, Status, Diflexx, Diflexx Duo, Sugarbeet Stinger Dry beans

35 Prepare for the future Develop a strategy What is the most important and second most important weed in field? Identify herbicides from different sites of action, different group numbers Mix it up! PRE fb POST, POST tank-mixes Create a spreadsheet; these are field/farm records Discuss resistant weeds with your ag service providers Don t forget about tillage or cultural practices

36 Thank you for your Attention and your Support Tom Peters Extension Sugarbeet Agronomist and Weed Control Specialist Thomas (office) (mobile)