New Grass and Broadleaf Weed Management Options in Coastal Bermudagrass Pastures

Transcription

1 New Grass and Broadleaf Weed Management Options in Coastal Bermudagrass Pastures L. Warren, F. Yelverton and T. Gannon North Carolina State University

2 Introduction Grass Weeds Interfere when striving for pure stands (horse owners, hog waste producers) Interfere with hay drying Generally not a health concern except johnsongrass Broadleaf Weeds Numerous, noxious, toxic, prickly (animals will not graze)

3 Common and / or Troublesome Weeds Large crabgrass Pigweed species Chickweed species Goosegrass* Blackberry Henbit Foxtail species Horsenettle Wild radish / mustard Sandbur species Buttercup species Paspalum species Curly dock Johnsongrass Italian ryegrass* *Possible 2012 additions 2008 Weed Survey Southern States (North Carolina)

4 Introduction Pastora (nicosulfuron + metsulfuron) Registered in 2010 for bermudagrass pastures Broadleaf as well as grass herbicide Perspective (aminocyclopyrachlor + chlorsulfuron) 2013 target registration date Broadleaf herbicide

5 Research Objectives To evaluate efficacy of Pastora and Perspective applied at various timings for postemergence control of important summer and winter pasture weeds To evaluate growth response of Coastal bermudagrass when treated at various timings

6 Plot sizes (4 reps) 6 x 15 to 8 x 25 ft plots Spray information Procedures Treatments applied with 18 in spacing 4-nozzle boom containing XR VS nozzles delivering 20 gpa at psi and 3 mph Evaluation parameters Control, bermuda stand reduction and chlorosis 0-100% scale; data subjected to ANOVA p=.05

7 Treatment List Pastora + NIS* 1 oz/a % Pastora + NIS 1.5 oz/a % Pastora + COC** 1 oz/a + 1% Pastora + COC 1.5 oz/a + 1% Perspective + NIS 1.19 to 4.76 oz/a % (2 to 2.5 oz/a) *NIS = Induce **COC = Agridex

8 % Control Large Crabgrass Control in Coastal Bermudagrass using Pastora 100 c a a c c c 80 Treated Apr 15 Rated Jul Treated Jun 8 Rated Jul oz/a Pastora % NIS Check 2009: Wake County Treated Jun 15 Rated Jul 8

9 2009 Wake County Trial Discussion Apr 15 application date: Italian ryegrass was 8 to 12 inches tall with density of 3 plants per ft2 Little barley was 3 to 5 inches and 1 plant per ft2 Large crabgrass had not germinated due to heavy winter weed infestations (0% control) Jun 3: 1 st harvest date Jun 8 application date: Large crabgrass just germinating at 1 to 2 leaves and 1 inch tall Jun 15 application date: Large crabgrass 3 to 4 leaves and 1 to 2 inches tall

10 Large Crabgrass Control and Coastal Bermudagrass Stand Reduction LSD (P=.05) Pastora 1 oz/a Apr 21 Pastora 1.5 oz/a Apr Pastora 1 oz/a Apr 21 and Jun Digsa Sep 3 Stand Stand May 7 Jun : Bladen County Stand Jul 21 Panoramic 0.25 pt/a Apr 21 Check 0.25% NIS added to all trts

11 2009 Bladen County Trial Discussion Winter weed infestation extremely light Apr 21: Trial initiated Large crabgrass 1 to 3 leaves and 0.75 inch tall and not heavily populated Panoramic bermuda effects observed through Jul Jun 4: 1 st harvest date Jun 25: 1 oz/a Pastora applied Jun 11 slightly stunted bermudagrass growth with peak symptoms at 2 WAT and full recovery by 4 WAT

12 Pastora 1 oz/a % NIS May 20, 2009 (4 WAIT)

13 Panoramic 0.25 pt/a % NIS May 20, 2009 (4 WAIT)

14 Goosegrass Control and Coastal Bermudagrass Stand Effects 7 19 lsd p=.05 Pastora + NIS 1 oz/a % Roundup Powermax + NIS 6 fl oz/a % ELEIN Jul 8 % COVER Jul : Bladen County Pastora + Roundup Powermax + NIS 1 oz/a + 6 fl oz/a % Check Jun 9, 2010 Application date

15 2010 Bladen County Trial Discussion Test area heavily infested with Italian ryegrass and other winter weeds Jun 4: 1 st cutting to remove mainly ryegrass Jun 9 application date: Heavy infestation of goosegrass ranging from 2 leaves to 2+ tillers and 2 to 6 inches tall (1 tiller and 4 inch tall avg.)

16 Check Pastora + NIS 1 oz/a % Treated Jun 9 Photo Jul 8

17 Italian Ryegrass Control Sampson Co. Rate Appl Date Eval Date Control 1.5 oz oz oz oz oz oz oz oz

18 Italian Ryegrass Trial Discussion Pastora applied at 1 oz/a or 1.5 oz/a provided excellent LOLMU control (>90%) regardless of timing LOLMU was heavily infested and ranged from 4 to 12 inches in height at any application date

19 Mar 8, 2011

20 Discussion Pastora Label Highlights Foxtail and ryegrass spp. (2 ); sandbur spp. (1.5 ) Johnsongrass (up to 18 ) Bahiagrass (before seedhead formation) Large crabgrass and goosegrass (suppression only) No restrictions; no long-term bermuda injury at any timing

21 % Control Buckhorn Plantain Control in Bermudagrass using Perspective lsd p=.05 Perspective 1.19 oz/a 60 Perspective 2.38 oz/a Perspective 4.76 oz/a 0 Mar 10 Spray Jun 3 Spray 2009: Wake County Oct 8 Spray Check 0.25% v/v NIS

22 2 WAT 4 WAT

23 % Chlorosis Effect of Perspective on Bermudagrass lsd p=.05 Perspective 1.19 oz/a Symptoms Jun 15; Recovery Jun 29 Perspective 2.38 oz/a Perspective 4.76 oz/a 0 Mar 10 Spray Jun 3 Spray 2009: Wake County Oct 8 Spray Check 0.25% v/v NIS

24 Perspective Effects on Various Weeds 1.19 oz/a DIORE 100% (Jun); 23% (Oct) oz/a RAPRA 80% and RUMCR 100% (Mar) oz/a RANSA, VERAR and TAROF 100% (Mar) oz/a STEME, CERVU, BRSNI, RANAR, GERCA, RUMCR, ARTVU 100%; CAPBP 98% (Jan) 2011 SOLCA and POLLA 100%; EUPCP 98%; CASOB 85%; CMIRA 60%; PAQIN 0% (May) 2011

25 Discussion Perspective (aminocyclopyrachlor + chlorsulfuron) Horsenettle Buckhorn & bdlf plantain Purple cudweed Curly & bdlf dock Carolina geranium Florida pusley Henbit Facelis White clover Hairy buttercup* Brazilian catsear Wild violet Corn buttercup* Purple deadnettle Goldenrod Common chickweed* Common lespedeza Hop clover Mustard / pigweed Lawn burweed Bdlf pink purslane Horseweed Common dandelion Bracted plantain Virginia buttonweed Lindheimer panicgrass Dichondra Florida betony Annual blue-eyed grass Dogfennel Sicklepod Polygonum spp. Dollarweed

26 Conclusions 1 or 1.5 oz/a Pastora provided excellent (>90%) control of large crabgrass up to 4 leaves, goosegrass up to 1 tiller and Italian ryegrass up to 12 inches in height. 1 oz/a Pastora applied in Jun (1 WA cutting) caused temporary bermudagrass growth reduction and discoloration (16%) by 2 WAT with total recovery by 4 WAT. Timely applications of Perspective up to 2.5 oz/a provided excellent (>90%) control of the common and troublesome NC pasture bdlf weeds tested except for wild radish (80%).

27 Conclusions Perspective also provided >90% control of dichondra, corn speedwell, common dandelion, Carolina geranium, mugwort, hairy bittercress, ladysthumb and dogfennel or 4.76 oz/a Perspective applied in Jun yellowed bermudagrass 11 or 14%, respectively 2 WAT; no injury symptoms were evident at 4 WAT. Pastora is and Perspective should be an excellent herbicide option for NC bermudagrass pasture growers.