Management of ventenata with indaziflam on conservation reserve program land

Jared A. Beuschlein

doi:10.7273/000004083

Ventenata dubia (Leers) Coss, an invasive annual grass in Eastern Washington and Northern Idaho, is a major threat to non-cropland areas of the Palouse. Threats to native prairie and land enrolled in the conservation reserve program (CRP) arise in the form of invasive species like ventenata and require active management. Indaziflam is a new herbicide that can control ventenata. However, there is limited knowledge on how application timing impacts ventenata control. A study was conducted to test the effect of indaziflam on ventenata and desirable native perennial grasses. Two CRP sites, one near Kendrick, ID and one near Albion, WA were chosen to assess indaziflam with or without rimsulfuron at different rates and ventenata timings (2-months PRE, 1-month PRE, early POST). Treatments included indaziflam (73 g ai ha-1, 102 g ai ha-1), indaziflam plus rimsulfuron (35.2 g ai ha1 + 71.5 g ai ha-1 ,53.3 g ai ha-1 + 71.5 g ai ha-1, 71.5 g ai ha-1 + 71.5 g ai ha-1 ), and imazapic (123 g ai ha-1). Visual assessment and biomass data from 2018 and 2019 validated the hypothesis that indaziflam caused a significant reduction in V. dubia density , regardless of timing of application or rate of indaziflam. Total mean biomass of perennial bunchgrasses did not decrease in treatments where ventenata biomass was reduced. The second study evaluated the tolerance native and introduced perennial grasses have to indaziflam. There is limited knowledge on how native grasses tolerate indaziflam. Desirable grasses assessed were bluebunch [Pseudoroegneria spicata (Pursh) Á Löve.], slender [Elymus trachycaulus (Link) Gould ex Shinners], and intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey]; Idaho (Festuca idahoensis Elmer) and sheep's fescue (Festuca ovina L); and prairie junegrass [Koeleria macrantha (Ledeb.) J.A. Schultes]. Treatments included indaziflam (44 g ai ha-1, 73 g ai ha-1, 102 g ai ha-1), rimsulfuron (52.5 g ai ha-1), propoxycarbazone (59 g ai ha-1), imazapic (123 g ai ha-1) and imazamox (44 g ai ha-1). Total perennial grass biomass was 57% greater when treated with indaziflam plus propoxycarbazone, indaziflam plus imazapic or indaziflam plus imazamox when compared to the nontreated. Perennial grass cover increased 88% when applied with indaziflam plus imazamox compared to the nontreated. The perennial grasses treated with indaziflam were larger than perennial grasses not treated with indaziflam suggesting no negative effect to application of indaziflam to these perennial grass species.

Management of ventenata with indaziflam on conservation reserve program land

Files and links (1)

Abstract

Metrics

Details