RESULTS OF AGRONOMIC AND WEED SCIENCE RESEARCH CONDUCTED IN SOUTH CENTRAL MONTANA

Transcription

1 RESULTS OF AGRONOMIC AND WEED SCIENCE RESEARCH CONDUCTED IN SOUTH CENTRAL MONTANA The Annual Report of the Investigations at and Administration of the Southern Agricultural Research Center, Huntley, Montana PROJECT TITLE: PROJECT LEADER: OBJECTIVES: METHODS: Weed Control in Seedling Ready Alfalfa Steven R. King, Weed Scientist, SARC, Huntley, MT To evaluate herbicide tolerance and weed control in seedling ready Alfalfa with application of glyphosate and competitive standards Herbicides were applied at two POST timings with a CO 2 backpack sprayer calibrated to deliver 10 gal/a using 8001XR nozzles spaced 18 inches apart. Weed response following herbicide applications was evaluated visually using a rating scale that ranged from 0 (no visible injury) to 100% (complete plant death) Weed control ratings were determined visually estimating the amount of weed biomass present in each plot compared to the non-treated control plots. Experimental site and herbicide application data are presented in Table 1 and Table 2. Table 1. Site information Field: C Variety: Silty Clay Loam Planting Date: 4/27/06 Variety: Round up ready alfalfa Planting Population: 12 lbs/a Row spacing: 7 inches Table 2. Herbicide application Treatment Timing: POST A Date Treated: 6/06/06 Time: 8:00 AM Soil Moisture (Surface): Dry Alfalfa 4 trifoliate wild Oat (AVEFA) 6-8 tiller, 6-10 tall Density: 8 M 2 Redroot pigweed (AMARE) Stage 1-5 tall Density: 6 M 2 Common Lambsquarter (CHEAL) 1-7 tall Density: 15 M 2 Kochia (KCHSC) Stage 1-5 tall Density: 3 M 2 Sunflower (HELAN) Stage 6-8 tall Density 2 M 2 Wild Buckwheat (POLCO) 3 vine Density: 8 M 2

2 Treatment Timing: POST B Date Treated: 7/28/06 Time: 9:00 AM Soil Moisture: Dry Alfalfa 4 regrowth Barnyard grass (ECGCH) 4 tall Density: 10 M 2 Redroot pigweed (AMARE) 4 regrowth Density: 12 M 2 Common Lambsquarters (CHEAL) 3 regrowth Density: 10 M 2 Kochia (KCHSC) 3 tall Density: 8 M 2 RESULTS: This experiment was conducted in Huntley, Montana to evaluate herbicide tolerance and weed control in seedling ready alfalfa with applications of glyphosate and competitive standards. Treatments were applied twice with the exception of Raptor. No injury was observed 7-14 days after the first application of herbicides. No difference in weed control occurred between the two glyphosate rates. At 14 days after the first application, pigweed, kochia, common lambsquarters and wild buckwheat were controlled significantly greater in plots treated with glyphosate compared to plots treated with Raptor +Select or Butoxone+Select. Common lambsquarters, kochia and wild buckwheat were controlled only 55, 49 and 45%, respectively, at 14 days after the first application with Raptor plus Select. Common lambsquarters, kochia and wild buckwheat were controlled 89, 86 and 58% with Butoxone plus Select 14 days after the first application. At 12 days after the second application alfalfa was injured 11% by the sequential application of Butoxone + Select. No injury was observed with the other treatments. Weed control did not differ between the two glyphosate rates and control of all species evaluated was 97% or greater at 47 days after sequential application. By 47 days after sequential application, Butoxone Select controlled barnyardgrass, redroot pigweed, common lambsquarters and kochia 95% or greater. Broadleaf weed control with Raptor was significantly lower than that provided by other herbicides.

3 TABLE 3: ALFALFA INJURY AND WEED CONTROL RATINGS-PAGE 1 Pest Type W Weed W Weed W Weed W Weed W Weed Pest Code AVEFA AMARE CHEAL KCHSC POLCO Redroot Pest Name Wild oat pigweed Lambsquarters Kochia Wild buckwheat Crop Name Alfalfa Rating Date 6/13/2006 6/13/2006 6/13/2006 6/13/2006 6/13/2006 6/13/2006 Rating Data Type injury control control Control control control Days After Last Applic Trt-Eval Interval 7 DA-A 7 DA-A 7 DA-A 7 DA-A 7 DA-A 7 DA-A No. Type Name Timing Rate Unit CHK 0 a 0 d 0 d 0 D 0 d 0 d 2 HERB WeatherMAX A 0.75 lb ae/a 0 a 94 a 95 a 91 A 89 a 85 a HERB WeatherMAX B 0.75 lb ae/a 3 HERB WeatherMAX A 1.5 lb ae/a 0 a 94 a 95 a 92 A 89 a 89 a HERB WeatherMAX B 1.5 lb ae/a 4 HERB Raptor A 5 oz/a 0 a 56 c 56 c 41 C 35 c 26 c HE RB Se lect B 8 o z/a 5 HERB Butoxone 200 A 4 pt/a 0 a 64 b 73 b 70 B 58 b 54 b HERB Butoxone 200 B 4 pt/a HE RB Se lect B 8 o z/a LSD (P=.05)

4 Standard Deviation TABLE 3: ALFALFA INJURY AND WEED CONTROL RATINGS PAGE 2 Pest Type W Weed W Weed W Weed W Weed W Weed Pest Code AVEFA AMARE CHEAL KCHSC POLCO Redroot Pest Name Wild oat pigweed Lambsquarters Kochia Wild buckwheat Rating Date 6/20/2006 6/20/2006 6/20/2006 6/20/2006 6/20/2006 6/20/2006 Rating Data Type injury control control control control Control Days After Last Applic Trt-Eval Interval 14 DA-A 14 DA-A 14 DA-A 14 DA-A 14 DA-A 14 DA-A No. Type Name Timing Rate Unit CHK 0 a 0 c 0 c 0 d 0 d 0 D 2 HERB WeatherMAX A 0.75 lb ae/a 0 a 100 a 100 a 100 a 100 a 94 A HERB WeatherMAX B 0.75 lb ae/a 3 HERB WeatherMAX A 1.5 lb ae/a 0 a 100 a 100 a 100 a 100 a 100 A HERB WeatherMAX B 1.5 lb ae/a 4 HERB Raptor A 5 oz/a 0 a 95 b 80 b 55 c 49 c 45 C HE RB Sel ect B 8 o z/a A DJ C OC B 1 % v/v 5 HERB Butoxone 200 A 4 pt/a 0 a 97 b 79 b 89 b 86 b 58 B HERB Butoxone 200 B 4 pt/a

5 HE RB Sel ect B 8 o z/a A DJ C OC B 1 % v/v LSD (P=.05) B Standard Deviation B TABLE 3: ALFALFA INJURY AND WEED CONTROL RATINGS - PAGE 3 Pest Type W Weed W Weed W Weed W Weed Pest Code ECHCG AMARE CHEAL KCHSC Barnyard Redroot Pest Name grass pigweed Lambsquarters Kochia Crop Code MEDSA Crop Name alfalfa Rating Date 8/4/2006 8/4/2006 8/4/2006 8/4/2006 8/4/2006 Rating Data Type injury control control control control Trt-Eval Interval 7 DA-B 7 DA-B 7 DA-B 7 DA-B 7 DA-B No. Type Name Timing Rate Unit CHK 0 b 75 a 0 c 0 c 0 c 2 HERB WeatherMAX A 0.75 lb ae/a 0 a 100 a 100 a 95 a 100 a HERB WeatherMAX B 0.75 lb ae/a 3 HERB WeatherMAX A 1.5 lb ae/a 0 a 100 a 100 a 98 a 100 a HERB WeatherMAX B 1.5 lb ae/a 4 HERB Raptor A 5 oz/a 0 a 95 b 80 b 58 b 40 B

6 HE RB Se lect B 8 o z/a 5 HERB Butoxone 200 A 4 pt/a 0 a 97 b 79 b 95 a 94 A HERB Butoxone 200 B 4 pt/a HE RB Se lect B 8 o z/a LSD (P=.05) Standard Deviation TABLE 3: ALFALFA INJURY AND WEED CONTROL RATINGS - PAGE 4 Pest Type W Weed W Weed W Weed W Weed Pest Code ECHCG AMARE CHEAL KCHSC Barnyard Redroot Pest Name grass pigweed Lambsquarters Kochia Crop Code MEDSA BBCH Scale Crop Name Alfalfa Rating Date 8/9/2006 8/9/2006 8/9/2006 8/9/2006 8/9/2006 Rating Data Type INJURY control control control control Rating Unit Days After Last Applic Trt-Eval Interval No. Type Name Timing Rate Unit CHK 0 b 0 b 0 c 0 c 0 c 2 HERB WeatherMAX A 0.75 lb ae/a 0 b 100 a 100 a 97 a 100 a HERB WeatherMAX B 0.75 lb ae/a 3 HERB WeatherMAX A 1.5 lb ae/a 0 b 100 a 100 a 98 a 100 a HERB WeatherMAX B 1.5 lb ae/a 4 HERB Raptor A 5 oz/a 0 b 98 a 74 b 59 b 31 b

7 HERB Select B 8 oz/a 5 HERB Butoxone 200 A 4 pt/a 11 a 100 a 92 a 93 a 94 a HERB Butoxone 200 B 4 pt/a HERB Select B 8 oz/a LSD (P=.05) Standard Deviation TABLE 3: ALFALFA INJURY AND WEED CONTROL RATINGS - PAGE 5 Pest Type W Weed W Weed W Weed W Weed Pest Code ECHCG AMARE CHEAL KCHSC Pest Name Barnyard grass Redroot pigweed Lambsquarter Kochia Crop Code BBCH Scale Crop Name Rating Date 9/13/2006 9/13/2006 9/13/2006 9/13/2006 9/13/2006 Rating Data Type injury control control control control Days After Last Applic Trt-Eval Interval No. Type Name Timing Rate Unit CHK 0 a 0 b 0 c 0 c 0 c 2 HERB WeatherMAX A 0.75 lb ae/a 0 a 100 a 100 a 99 a 100 a HERB WeatherMAX B 0.75 lb ae/a 3 HERB WeatherMAX A 1.5 lb ae/a 0 a 100 a 100 a 100 a 100 a HERB WeatherMAX B 1.5 lb ae/a 4 HERB Raptor A 5 oz/a 0 a 100 a 88 b 75 b 55 b

8 HERB Select B 8 o z/a 5 HERB Butoxone 200 A 4 pt/a 0 a 100 a 98 a 95 a 95 a HERB Butoxone 200 B 4 pt/a HERB Select B 8 o z/a LSD (P=.05) Standard Deviation