Identification of herbicides for use in native forb seed production Shock, Feibert, Saunders, & Shaw OSU Malheur Experiment Station, Ontario Identification of post-emergence herbicides for use in native forb seed production E. umbellatum, Sulfur-flower buckwheat P. acuminatus, Sand penstemon P. deustus, Hot rock penstemon P. speciosus, Showy penstemon L. dissectum, Fernleaf biscuitroot L. triternatum, Nineleaf biscuitroot Lomatium grayi, Gray biscuitroot Identification of post-emergence herbicides for use in native forb seed production Post-emergence treatment Rate lb ai/acre Untreated Buctril 2.0 EC Goal 2XC Select 2.0 EC + Herbimax Prowl H2O 3.8 C Caparol FL 4.0 Outlook 6.0 EC Lorox 50 DF 0.125 0.125 0.094 + 1% v/v 1 0.8 0.656 0.5 Identification of post-emergence herbicides for use in native forb seed production 2006 seven post-emergence treatments and a check A. 5-ft-wide plots perpendicular to the forb rows B. 4 reps, randomized complete block design C. Applied May 24 at 30 psi, 2.63 mph, in 20 gal/acre using 8002 nozzles, three nozzles spaced 20 inches apart D. Plant injury rated visually on May 31, June 15 and 30. 2007 A. Same treatments, rates, methods, plots, and rates B. Applied on April 24 C. Plant injury rated visually on May 1, 11, 25, and June 12 D. Seed of three species harvested as it matured. Identification of post-emergence herbicides for use in native forb seed production 2008 A. Same treatments, rates, methods, plots, and rates B. Applied on March 12 C. Irrigated April 5-June 24, 1 inch every 2 weeks D. Plant injury rated visually several times. Seed of five species harvested as it matured. 2009 A. Same treatments, rates, methods, plots, and rates B. Applied on March 20 C. Irrigated 1 inch every 2 weeks D. Plant injury rated visually several times. E. Seed of two species harvested as it matured. Seed yield response in 2008 to repeated annual postemergence herbicides applied 2006, 2007, and 2008. Sh o w y P. Sh a r p l e a f Su l f u r - F . Ni n e l e a f Ho t r o c k 1200 Seed yield , lb /acre 1000 800 600 400 200 0 Hand Buct r i l G oal Sel ect Pr ow l Capar ol O ut l ook Lor oxLSD ( 0. 05) He rb ic i d e tre a tm e n t Identification of post-emergence herbicide mixtures for use in native forb seed production Four species had been planted in the fall of 2006 for more extensive herbicide screenings. 2008 and 2009: • Tested rates and combinations of Prowl and Outlook applied on March 12 (‘08) or March 20 (’09) plus Select applied later. • Irrigated 1 inch every 2 weeks • Plant injury rated visually several times. • Seed was harvested as it matured. Treatment Rate (lbs ai/acre) Weed free, untreated control Select 2.0 EC 0.094 Prowl 0.95 Prowl 1.19 Prowl 1.43 Outlook 0.84 Outlook 0.98 Prowl + Outlook 0.95 + 0.66 Prowl + Outlook 0.95 + 0.84 Prowl + Outlook 0.95 + 0.98 Prowl + Outlook 1.19 + 0.66 Prowl + Outlook 1.19 + 0.84 Prowl + Outlook 1.19 + 0.98 Forb seed yield response to post-emergence herbicides applied March 2008, Sh o wy P. Sh a rp le a f P. Su lfu r-F . B. 1400 Seed yield , lb /acre 1200 1000 800 600 400 200 0 Ha n d S e l e c tP r o w lP r o w lP r o w Ol u t l oOo ku t l o oPk + O P + O P + O P + O P + O P + O He rb ic i d e tre a tm e n t Identification of post-emergence herbicides for use in native forb seed production Preliminary conclusions from 2007: Conclusions from 2008 and 2009. A. In general there tended to be less observed foliar injury with the use of Prowl, Outlook, and Select in 2006 and 2007. With early application, no foliar symptoms in 2008 or 2009. B. Lomatium grayi and L. dissectum flowered in 2009. C. P. specious and P. deustus resisted Prowl, Outlook, and Select. P. deustus showed good seed yield. P. acuminatus resisted Prowl and Outlook and demonstrated good seed yield. Identification of post-emergence herbicides for use in native forb seed production Preliminary conclusions from 2007: Conclusions from 2008 and 2009. D. All species had foliar tolerance with no obvious symptoms following early herbicide applications. E. Five species had good seed yield and only Lomatium triternatum had reduced seed yield when treated with Buctril. F. The rates and combinations of Prowl and Outlook were applied on 4 species. They produced no foliar damage systems and did not reduce seed yields for the three species that had seed production.