IDENTIFICATION OF HERBICIDES FOR USE IN NATIVE FORB SEED PRODUCTION. Corey Ransom and Kim Edvarchuk

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1 IDENTIFICATION OF HERBICIDES FOR USE IN NATIVE FORB SEED PRODUCTION Corey Ransom and Kim Edvarchuk

2 Objective Identify herbicides for weed management in forb seed production. - Astragalus filipies - Dalea ornata - Dalea searlsiae -Crepisacuminata

3 Preliminary Response of Astragalus filipies Prowl H 2 O Outlook Olympus Treflan Sencor Kerb

4 Preemergence Herbicide Screening Difficulty in achieving uniform germination has prevented the generation of additional information on preemergence herbicides. With larger seed quantities, preemergence testing will be done in field trials. Research results for 2008 are from field evaluations of postemergence herbicide tolerance in Astragalus filipies and Dalea ornata.

5 Postemergence Herbicide Screening, 2008 Conducted on fields established in 2005 as transplants from conetainers. Plants were spaced 0.5 m. Herbicide treatments applied May 13, Applications made with a shielded bicycle sprayer at 20 gpa and 30 psi. To account for variability, initial height and width were measured for every plant.

6 Herbicide Treatments on Astragalus filipies Herbicide Rates lb ai/a product Prowl H 2 O pt Outlook oz Goal pt Chateau + NIS oz Sencor + NIS lb Buctril pt NIS at 0.25% v/v 2,4-DB pt MSO at 1.0% v/v Transline pt Paramount + MSO lb Raptor + MSO oz Around 15 cm tall at application. Injury evaluated May 23 (10 DAT) and July 25. Heights measured May 17 (initial) and June 19.

7 Astragalus Injury on May 23 in Response to Herbicides Visual injury (%) 20 Prowl H2O Outlook Goal Chateau + NIS Sencor + NIS Buctril 2,4-DB Transline Paramount + MSO Raptor + MSO 0 Transline injury high initially

8 Astragalus Injury on July 11 in Response to Herbicides Visual injury (%) 20 Prowl H2O Outlook Goal Chateau + NIS Sencor + NIS Buctril 2,4-DB Transline Paramount + MSO Raptor + MSO 0 Transline injury maintained and Goal increased 2,4-DB, Paramount, and Raptor increased

9 Astragalus Plant Height in Response to Herbicides Plant height (cm) 5 Untreated Prowl H2O Outlook Goal Chateau + NIS Sencor + NIS Buctril 2,4-DB Transline Paramount + MSO Raptor + MSO 0 Transline reduced plant height

10 Astragalus Plant Width in Response to Herbicides Plant width (cm) 4 2 Untreated Prowl H2O Outlook Goal Chateau + NIS Sencor + NIS Buctril 2,4-DB Transline Paramount + MSO Raptor + MSO 0 Transline reduced plant width

11 Relationship of Visual Ratings and Plant Height and Width Change in plant height (cm) P > R 2 = 0.47 Change in plant width (cm) P > R 2 = Injury (%) Injury (%)

12 Herbicide Injury in Astragalus filipies Transline Paramount

13 Herbicide Treatments on Dalea ornata Herbicide Rates lb ai/a product Sencor + NIS lb Buctril pt Paramount + MSO lb Raptor + MSO oz NIS at 0.25% v/v MSO at 1.0% v/v Very little re-growth at the time of application. Injury evaluated May 23 (10 DAT) and July 11. Heights measured May 17 (initial) and June 19.

14 Herbicide Treatments on Dalea ornata No visual injury observed for any herbicide treatment on either evaluation date.

15 Dalea Plant Height in Response to Herbicides Plant height (cm) 10 Untreated Sencor + NIS Buctril Paramount + MSO Raptor + MSO 0 No differences in plant height

16 Dalea Plant Width in Response to Herbicides Plant width (cm) 10 Untreated Sencor + NIS Buctril Paramount + MSO Raptor + MSO 0 No differences in plant width

17 Conclusions 1. Once established, Astragalus filipies appears to tolerate several herbicides. 2. Established Dalea ornata was not injured by postemergence herbicide, but this may be due to delayed breaking of dormancy. 3. There may be great potential to utilize herbicides when plants are dormant. 4. Additional research will focus on the effects on seed production following treatment with herbicides. 5. Another project will evaluate establishment following Plateau applications.

18 Research support from: USDI BLM Great Basin Restoration Initiative, GBNPSIP, and USDA FS Rocky Mountain Research Station