Yellow toadflax (Linaria vulgaris) management with wiper- and broadcast-applied glyphosate under greenhouse conditions

Abstract

Yellow toadflax [Linaria vulgaris (Mill.)] is an invasive perennial broadleaf weed of the Northern Great Plains region that negatively impacts forage production and wildlife habitat. Few management tactics exist that effectively control the weed species. Glyphosate is a nonselective herbicide that could effectively manage yellow toadflax but is rarely used in pasture/rangeland system due to injury of desirable vegetation. Wiper-applied glyphosate could selectivity control yellow toadflax with minimal injury on desirable vegetation. Greenhouse experiments were conducted to determine the effectiveness of various concentrations and rates of wiper- and broadcast-applied glyphosate on flowering yellow toadflax plants. Plants treated with glyphosate via wiper applicator exhibited injury (63%–80%) and reduced fresh biomass (53%–73%) compared to the nontreated plants. However, the incurred injury and reductions of fresh biomass were not different across the tested glyphosate concentrations. Plants treated with glyphosate via broadcast application(1260 and 2520 g ae ha⁻¹) exhibited injury (48%–62%), but biomass was no different when compared to the nontreated plants. The results of the experiments suggest that labeled glyphosate concentrations (33%–75%) for wiper applications provide similar control of yellow toadflax under greenhouse conditions. Broadcast glyphosate applications caused injury on the treated plants but did not decrease biomass compared to nontreated plants. Therefore, wiper-applied glyphosate may be a more viable option to manage yellow toadflax.