FORB RESPONSE TO HERBICIDES FOR SEED PRODUCTION AND RANGELAND RESTORATION Corey Ransom Objective – Seed Production Identify herbicides for weed management in forb seed production. - Astragalus filipies - Dalea ornata - Dalea searlsiae Herbicide Tolerance Trials, 2011 Field trials at USU research farm Planted: 8 lb PLS/acre Acid scarified and mixed with corn hulls Planter: Hege coneseeder Plots size: 5 ft by 30 ft replicated 4 times Applications: CO2backpack sprayer, 20 GPA at 30 psi Astragalus filipies -Basalt Milkvetch Dry River germplasm Dalea ornata - Western Prairie Clover Aridlands germplasm Postemergence Herbicides – Astragalus filipies Herbicide Rates lb ai/A product 2,4-DB 0.25 1.0 pt 2,4-DB 0.5 2.0 pt Basagran + COC 0.5 1.0 pt Buctril 0.25 1.0 pt 0.25 + 0.125 1.0 + 0.5 pt Paramount + COC 0.248 5.3 oz Pursuit + COC 0.047 3.0 oz Raptor + COC 0.063 4.0 oz 2,4-DB + Buctril Raptor + Basagran + COC COC at 1.0 pt/acre 0.063 + 0.25 4.0 oz + 0.5 pt • Planted October 18, 2010. • Treated June 21, 2011. • Evaluated 36 days after treatment. Astragalus filipies injury and density change in response to postemergence herbicides. Treatment Untreated 2,4-DB 2,4-DB Bentazon + COC Bromoxynil 2,4-DB + bromoxynil Quinclorac + MSO Imazethapyr + COC Imazamox + COC Imazamox + bentazon + COC LSD (0.05) COC at 1.0 pt/acre Rate lb ae/or ai/A 0.25 0.5 0.5 0.25 0.25 + 0.125 0.25 0.047 0.063 0.063 + 0.25 Evaluations 36 DAT Density Injury reduction _______________%_______________ 0 21 1 29 9 29 8 29 30 36 14 37 19 42 8 19 7 28 13 26 14.7 NS Challenges of plant persistence appear to be independent of herbicide treatment! Need to better understand seedling survival. Postemergence Herbicides –Dalea ornata Herbicide Rates lb ai/A product 2,4-DB 0.25 1.0 pt Basagran + COC 0.25 1.0 pt Buctril 0.25 1.0 pt 2,4-DB + Buctril 0.25 + 0.125 1.0 + 0.5 pt Pursuit + COC 0.047 3.0 oz Raptor + COC 0.063 4.0 oz Raptor + Basagran + COC 0.63 + 0.25 4.0 oz + 0.5 pt COC at 1.0 pt/acre • Planted June 15, 2011. • Application made August 19. • Injury evaluated 22 days after treatment. Dalea ornata injury, plant density increase, and flowering in response to postemergence herbicides. Treatment Untreated 2,4-DB Bentazon + COC Bromoxynil 2,4-DB + bromoxynil Imazethapyr + COC Imazamox + COC Imazamox + bentazon + COC LSD (0.05) COC at 1.0 pt/acre Rate lb ae/or ai/A 0.25 0.5 0.25 0.25 + 0.125 0.047 0.063 0.063 + 0.25 Evaluations 22 DAT Density Injury increase _______________%_______________ 0 22 5 22 11 31 10 15 18 14 6 14 4 3 9 21 NS NS Flowers no/plot 169 188 200 136 148 173 162 185 NS Preemergence Treatments on Dalea ornata Herbicide Rates lb ai/A Product Prowl H2O 0.5 1.1 pt Prowl H2O 1.0 2.1 pt Prowl H2O 1.5 3.2 lb Outlook 0.75 1.0 pt Nortron 1.0 2.0 pt Several plots treated with Prowl H2O at 2.1 pt for combination with postemergence treatments • Planted August 26, 2011. • Sprayed August 27, 2011. • Densities counted October 13, 2011. Dalea ornata plant densities in response to preemergence applied herbicides following August 26, 2011 planting. Treatment Untreated Pendimathalin Pendimathalin Pendimathalin Pendimathalin Pendimathalin Pendimathalin Dimethenamid-p Ethofumesate LSD (0.05) Rate lb ai/A 0.5 1.0 1.5 1.0 1.0 1.0 0.75 1.0 Plant density no/plot 137 181 182 172 173 200 188 171 179 NS Preemergence Herbicide Effects on Weed Pressure, August 26, 2011 planting. Untreated Pendimethalin 1.5 lb ai/acre Dimethenamid-p 0.75 lb ai/acre Ethofumesate 1.0 lb ai/acre Visible Injury from Preemergence Herbicides on October 10, 2011. Untreated Pendimethalin 1.5 lb ai/acre Dimethenamid-p 0.75 lb ai/acre Ethofumesate 1.0 lb ai/acre Conclusions of Herbicide Trials • Astragalus filipies and Dalea ornata appear to be tolerant to several postemergence herbicides. • All preemergence treatments caused visible injury. • No herbicide treatments reduced stand. • Seed yield and viability needs to be evaluated to demonstrate herbicide utility. Objective – Rangeland Restoration Evaluate native species response to herbicides applied to control downy brome. How will they handle exposure to these herbicides after seeding? Initiation of Field Establishment Trial, 2009 Nephi, UT Application timings: Spring and Fall 2009 Herbicides: Plateau 1, 2, 4, 6, 8, 10, and 12 fl oz Olympus, Outrider, Matrix, Oust Planting timings: Fall 2009 Initiation of Field Establishment Trials, 2009 Species planted at Nephi: Lupinus sericeus Globe mallow Sphaeralcea Sulfur flower BW Eriogonum umbellatum Big blue penstemon Penstemon cyaneus Prairie clover Dalea ornata Searle’s Prairie Clover Dalea searlsie Utah sweetvetch Astragalus filipies Silky lupine Anatone Bluebunch wheatgrass Sherman Big bluegrass Basalt Milkvetch Establishment 8 Spring Fall Plants (no/plot) 6 4 2 0 16 .031 .063 0.94 .125 0.16 0.19 US DER RIX UST 0 . P 0 0 0 0 O T T T M TRI AT T T T T A A A Y M A A A A L L L L U P P P O O PL PL PL PL R T UN Herbicide Basalt Milkvetch Establishment 8 7 Plants (no/plot) 6 Spring Fall 5 4 3 2 1 -0.05 0.00 0.05 0.10 0.15 Imazapic rate (lb ai/acre) 0.20 0.25 Conclusions • Limited data demonstrates that germination will be influenced by herbicides applied to control downy brome • A greater understanding of individual species tolerance and herbicide dissipation rated in different soils are needed Support: Great Basin Native Plant Selection and Increase Project Silky Lupine Establishment 5 Spring Fall Plants (no/plot) 4 3 2 1 0 16 .031 .063 0.94 .125 0.16 0.19 US DER RIX UST 0 . P I 0 0 0 0 O AT T T T AT AT AT LAT LYM TR M A A A L L U L L L L P P P O O P P P P R T UN Herbicide Grass ?? Establishment 25 Spring Fall Plants (no/plot) 20 15 10 5 0 16 .031 .063 0.94 .125 0.16 0.19 US DER RIX UST 0 . P I 0 0 0 0 O AT T T T AT AT AT LAT LYM TR M A A A L L U L L L L P P P O O P P P P R T UN Herbicide