Evaluation of foramsulfuron for poverty oat grass [Danthonia spicata (L.) P. Beauv. ex Roem. & Schult.] and rough bentgrass (Agrostis scabra Willd.) management in lowbush blueberry (Vaccinium angustifolium Ait.)

Abstract

The susceptibility of poverty oat grass and rough bentgrass to foramsulfuron was assessed in greenhouse and field experiments. A dose response study was conducted in a greenhouse with treatments consisting of 0, 4.4, 8.8, 17.5, 35, 70, 140, and 280 g foramsulfuron ha−1. Field experiments were conducted using a similar dose response and also included industry standard fluazifop-P-butyl and sethoxydim applications. Foramsulfuron application rates of 4.04 ± 0.73 and 6.6 ± 1.3 g a.i. ha−1 reduced poverty oat grass biomass by 50% in the greenhouse. In contrast, 4.4 g a.i. ha−1 foramsulfuron caused >70% reduction in rough bentgrass biomass in the greenhouse. In the field, 280 g a.i. ha−1 of foramsulfuron was required to reduce poverty oat grass total and flowering tuft density and >35 g a.i. ha−1 (registered foramsulfuron rate) was required to reduce flowering tuft inflorescence number by 50%. In contrast, rough bentgrass was injured by 4.4 and 8.8 g a.i. ha−1 of foramsulfuron and total and flowering tuft density and flowering tuft inflorescence number were reduced by all other foramsulfuron rates evaluated. Foramsulfuron application rates of 13.1 ± 2.4, 10.3 ± 1.2, and 5.4 ± 0.9 g a.i. ha−1 reduced rough bentgrass total tuft density, flowering tuft density, and tuft inflorescence number, respectively, by 50%. Lowbush blueberry growers can consider foramsulfuron for postemergence management of rough bentgrass, but additional research is required to identify new herbicides for postemergence poverty oat grass management.