Herbicide Resistance in Kochia, Horseweed and Ragweed. Phil Stahlman Weed Scientist Kansas State University Agricultural Research Center-Hays

Transcription

1 Herbicide Resistance in Kochia, Horseweed and Ragweed Phil Stahlman Weed Scientist Kansas State University Agricultural Research Center-Hays

2 Kochia Kochia scoparia aka fireweed, burningbush, tumble weed, summer-cypress, others Introduced from Eurasia ~1900; spread throughout western U.S. and Canada during 1930 s. Drought and salt tolerant broadleaf species. - roots typically penetrate 6-8 ft deep Alternate lance-shaped leaves with fringed hairs on margins. - about 6-10X longer than wide Branched stems up to 7 ft - shades of green, reddish green

3 Phenotypic Variation

4 Kochia Kochia scoparia aka fireweed, burningbush, tumble weed, summer-cypress, others Cross pollination and pollen flow over long distances ensures high genetic diversity. Genetic diversity is as great within as between populations. Prone to herbicide resistance.

5 Protogynous Flowering female stigmas mature before male anthers Courtesy of Phil Westra, Colorado State University

6 Tumble Weed Seed Dispersal

7 In the Pacific Northwest, kochia moved ~2.5 miles in 6 weeks (Thill, U of ID) Along I-70 in western KS

8

9 Historical Perspective of GR Kochia Low use rate hastens selection for resistance. First lack of control problems not due to abiotic factors were in low use rate markets in SW Kansas. Monsanto greenhouse testing in 2005 showed slightly elevated tolerance but not resistance. LOC documented in a field trial in 2007; confirmed in greenhouse testing. Three additional sites identified and confirmed. Distance suggested resistance developed independently.

10 Ingalls, KS July 2007 RT3 88 oz/a John Fenderson, Monsanto

11 GR 50 and Resistance Index values for 10 kochia populations in response to glyphosate at 21 DAT (Waite et al. ) Population GR 50 Res. Index Ingalls, KS Norton, KS Stevens Co., KS Syracuse, KS Hays, KS Minidoka Co., ID Prosser, WA Eden, ID IAREC, WA Jerome, ID

12 Trail of kochia plants in a soybean field near Colby, KS in 2007 after spraying three times with glyphosate. The dispersal plant came from an adjacent field of Roundup-Ready corn (Stahlman).

13 Glyphosate dose response in kochia

14 Response of Kochia Plants Grown Outside to Glyphosate Susc. Accession KS7 control 0x 2x 4x 8x Godar and Stahlman

15 Response of Kochia Plants Grown Outside to Glyphosate Susc. Accession KS31 control 0x 2x 4x 8x Godar and Stahlman

16 Phillip Co. KS 2010; grower application at 10 gpa April 21: 42 oz Buccaneer Plus + 9 oz 2,4-D LVE + AMS + NIS June 2: 49 oz Buccaneer Plus + 1 oz Sharpen + AMS + NIS (1 DPP) June 24: 31 oz Buccaneer Plus oz Cadet + COC + Guardian (POST)

17 Lane Co. KS 2010 No-till 18 years; grower application - 32 oz Roundup + 10 oz Salvan (5 lb 2,4-D acid) 2 weeks preplant - 60 oz Roundup oz Cadet + MSO + sticker POST at 10 gpa - Resprayed with same mix at 15 gpa

18 Haskell Co. KS 2010 Variable Control

19 Variable Control

20 Greeley Co. KS 2010

21 Greeley Co. KS

22 Edge of field double sprayed Gray Co., KS 2010 Glyphosate rate unknown

23 Effective dose for 50% mortality (GR 50 ) and resistance index for nine kochia populations in response to glyphosate at 21 DAT (Godar & Stahlman, 2010). Population Kansas County GR 50* Res. Index Lane # Scott # Scott # Russell # Phillips # Hodgeman # Lane # Norton # Ellis known susceptible *kg ha -1

24 Shikimic acid Glyphosate (Roundup) molecule EPSPS enzyme (protein)

25 Shikimate Assay of 2010 Populations

26 Cheyenne Rawlins Decatur Norton Phillips Sherman Thomas Sheridan Graham Rooks Wallace Logan Gove Trego Ellis Russell Suspect Confirmed GR-Kochia Populations glyphosate-resistant sampled Suspect GR-Kochia fall kochia 2010 populations populations sampled as of fall October Greeley Wichita Scott Lane Ness Hamilton Kearney Finney Hodgeman Rush Pawnee Edwards Several others likely but not confirmed. Prevailing wind direction Gray Ford Stanton Grant Haskell Kiowa Morton Stevens Seward Meade Clark Comanche Godar & Stahlman

27 Response of 44 Kochia Populations in Western Kansas to Glyphosate, August 2011 (Godar & Stahlman) Red = resistant; green = susceptible Based on shikimate accumulation, 4 plants at each site

28 Lamar, CO, August 2011 Sheridan Lake, CO, August 2011 Photo: Brachtenbach Photo: Brachtenbach Idalia, CO, August 2011 Yuma, CO, Photo: Brachtenbach August 2011 Photo: Westra

29 Southern Alberta, 2011 Photo courtesy of Hugh Beckie, Ag Canada

30 Confirmed GR Kochia, 2012

31 EPSPS gene amplification confers glyphosate resistance in A. palmeri genomic copy number of EPSPS expression of EPSPS transcript EPSPS protein level EPSPS enzymatic activity Amplification (increased copy number) of EPSPS led to over-production of EPSPS enzyme, so that even in the presence of glyphosate there is an abundant supply of uninhibited EPSPS Susceptible Resistant Powles S B PNAS 2010;107:

32 Low shikimate accumulation correlates with EPSPS gene amplification (Westra et al.) Δ ng shikimate ul Relative EPSPS:ALS genomic copy number

33 Relative EPSPS:ALS transcript abundance EPSPS genomic copy number correlates with EPSPS transcript abundance (Westra et al.) Central dogma R² = Relative EPSPS:ALS genomic copy number

34 EPSPS genomic copy number correlates with increased EPSPS protein abundance (Westra et al.) A. palmeri S R Susceptible K. scoparia Resistant 55 kda 43 kda EPSPS 34 kda Sus. Kochia very low EPSPS protein level Res. Kochia dark bands indicate high EPSPS protein level

35 Weed Management After Wheat harvest in Western Kansas, th week of August 1503 fields % % Sprayed Tilled Nothing %

36 Glyphosate-resistant Kochia scoparia: a threat to No-till in the central Great Plains Wray, CO (2011), Westra

37

38 Online Crop Consultant Survey

39 Web-based Crop Consultant Survey respondents representing ~1.2 million acres Major questions Presence of GR kochia? Rate and frequency of glyphosate application? Effectiveness of alternative management practices? Three periods of time

40 Percentage of respondents Survey Results Effectiveness of glyphosate for kochia control in RR crops Before Mostly controlled Frequently controlled Occasionally controlled Rarely controlled

41 Survey Results What percentage of fallow fields were infested with kochia?

42 Survey Results What percentage of the fields had GR kochia in ?

43 Survey Results What was the most common acid equivalent (ae) rate of glyphosate in fallow fields?

44 Survey Results What was the most common frequency of glyphosate application (per season) in fallow fields?

45 Alternative practices In what percentage of the fields were the following practices used in and how effective were those practices?

46 Survey Results

47 Emergence Timing and Persistence In Manitoba, kochia emergence began at 50 cumulative GDD, Tbase 0 C, and continued into late summer. Earlier than other common weed species. Surface and shallow emergence, fatal germination at 80 mm. Few seeds remained in the seed bank at end of season. Schwinghamer and Van Acker Weed Sci. 56:37-41 P. Westra

48 Kochia Emergence Trials Lingle Mitchell & Scottsbluff Ft Collins Stockton Hays Ness City Garden City Location Garden City, KS Hays, KS Ness City, KS Stockton, KS Ft. Collins, CO Mitchell, NE Scottsbluff, NE Lingle, WY Site crop crop non-crop non-crop non-crop crop - dryland - irrigated non-crop non-crop non-crop

49 Hays, KS cropland vs noncropland, Cumulative % kochia emergence Cumulative GDD (Jan 1) non crop observed emergence crop observed emergence non crop predicted emergence crop predicted emergence

50 Kochia Emergence Earliest emergence in KS after March 15. Earliest emergence in NE and WY after April % of seedlings emerged within first 2 weeks. At most sites a few plants emerged as late as July.

51 Implications First flush emergence emphasizes the need for early season weed control. Later emerging plants indicate the need for extended periods of weed control. Farming practices appear to be selecting for later and more prolonged emergence of kochia.

52 Kochia control 5-6 WA PRE in early spring across 4 trials in Kansas, Hays, Gorham, Scott City, Tribune Stahlman et al., KSU Ag Research Center-Hays

53 Control, % Kochia Control with Soil-Applied Dicamba ± 3 DAT 41 ± 2 DAT 61 ± 4 DAT 8 fl oz/a fl oz/a fl oz/a fl oz/a Means of 3 trials at Hays, Garden City, and Tribune, KS, 2012

54 Kochia Control with PRE Herbicides 75 DAT, Hays KS, Applied March 5, 2012 Exp 1201

55 POST kochia control 3-4 WAT averaged across eight trials in KS (4), CO (2), MT (1) and NE (1). (%) Stahlman et al., KSU Agricultural Research Center-Hays

56 GR Kochia Control, Hays KS, 2011 *fl oz per acre; RUPM and RUPM + Clarity treatments included 2% w/v AMS May 20, 2011, 17.5 gpa, kochia 2-7 tall Exp 1114

57 GR Kochia Control, Hays KS, 2011 *fl oz per acre; RUPM and RUPM + Clarity treatments included 2% w/v AMS May 20, 2011, 17.5 gpa, kochia 2-7 tall Exp 1114

58 GR Kochia Control, Hays KS, 2011 *fl oz per acre; RUPM and RUPM + Clarity treatments included 2% w/v AMS May 20, 2011, 17.5 gpa, kochia 2-7 tall Exp 1114

59 Growth Stage Affects Kochia Response to Clarity, Hays KS, gpa Exp 1107

60 Effect of Spray Volume on Kochia Control 12 DAT, Grainfield KS, 2012 Gallons per acre Treatment Rate RT3 + Clarity + 2,4-D LV6 + Class NG RT3 + Starane NXT + Class Act NG Laudis + Starane NXT + MSO + Class Act NG Gramoxone SL + Metribuzin 75 DF + Act. 90 NIS + Class Act NG Gramoxone SL + Linex 4L + Act. 90 NIS + Class Act NG 32 oz + 16 oz + 10 oz + 2.5% 32 oz + 14 oz + 2.5% 3 oz + 14 oz + 1% + 2.5% 3 pt + 8 oz + 0.5% + 2.5% 3 pt pt + 0.5% + 2.5% 40 f 50 e 47 e 62 d 67 cd 68 bcd 63 d 72 bc 75 b 73 bc 86 a 87 a 82 a 87 a 87 a 64 B 72 A 73 A Sprayed 7/18/12; kochia 6-18 tall Exp 1210

61 Effect of Spray Volume on Kochia Control 28 DAT, Grainfield KS, 2012 Gallons per acre Treatment Rate RT3 + Clarity + 2,4-D LV6 + Class NG RT3 + Starane NXT + Class Act NG Laudis + Starane NXT + MSO + Class Act NG Gramoxone SL + Metribuzin 75 DF + Act. 90 NIS + Class Act NG Gramoxone SL + Linex 4L + Act. 90 NIS + Class Act NG 32 oz + 16 oz + 10 oz + 2.5% 32 oz + 14 oz + 2.5% 3 oz + 14 oz + 1% + 2.5% 3 pt + 8 oz + 0.5% + 2.5% 3 pt pt + 0.5% + 2.5% 67 c 68 c 67 c 70 c 75 bc 72 c 75 bc 87 a 85 ab 95 a 95 a 96 a 95 a 94 a 96 a 80 A 84 A 83 A Sprayed 7/18/12; kochia 6-18 tall Exp 1210

62 Postemergence Kochia Control in Fallow, Hays KS 2012 Treatment* Rate oz/a, v/v 14 DAT 35 DAT Laudis + Atrazine + MSO % 20 f 20 e Laudis + Atrazine + Banvel + MSO % 68 d 81 b Laudis + Buctril + COC % 45 e 40 d Laudis + Starane NXT + MSO % 90 ab 91 ab Huskie + NIS % 68 d 69 c Huskie + Atrazine + NIS % 81 bc 80 bc Huskie + Starane + NIS % 93 a 98 a Starane NXT + NIS % 78 c 81 b Gramoxone SL + Metribuzin + NIS % 81 bc 83 b *All plus 2% w/v AMS Applied May 21, 2012, Kochia 2-12 Exp 1202

63 Marestail or Horseweed (Conyza canadensis) Member of the Composite (sunflower) plant family Native to North America Not much of an agronomic problem prior to no-till Propensity to develop herbicide resistance

64 Marestail Stages of Growth Marestail is generally a winter annual weed that overwinters in the rosette stage, bolts in the spring, and produces seed in the summer. Seedling Rosette Bolting Seed head

65 Managing Marestail Timing, Timing, Timing! 2,4-D, dicamba, Sharpen and/or residual herbicides in fall and early spring burndown in no-till. Atrazine + 2,4-D in corn. Liberty for late burndown control and in LL soybeans. Don t skimp on rate or appropriate spray additives.

66 Managing Marestail Recent Research from Washington University and Monsanto indicates that some glyphosate resistant marestail is actually more susceptible to glyphosate with cooler temperatures than warmer temperatures because the mechanism or resistance is due to compartmentalization in the vacuole, which occurs more slowly at lower temperatures.

67 Burndown of rosette marestail at Manhattan, KS in 2011 (Peterson and Thompson). Rate 1WAT 5/24 6/10 6/24 Cost oz/a % $/A Sharpen + MSO ,4-D Clarity Clarity Ignite + AMS LSD (5%)

68 2,4-D and Dicamba Preplant Intervals in Soybeans 7 days for up to 1 pt 2,4-D LV4 15 days for 1-2 pt 2,4-D LV4 or up to 1 pt Amine 4 30 days for 1-2 pt of 2,-D Amine 4 14 days following up to 8 oz Clarity and 1 inch of rain or irrigation.* 28 days following 8-16 oz of Clarity and 1 inch of rain or irrigation.* * Do not apply Clarity preplant to soybeans in areas with less than 25 inches annual precipitation. 30 days for Banvel.

69

70

71 Questions?