Published online by Cambridge University Press: 12 June 2017
Optimal rates and time of application of glyphosate for control of the native perennial bluejoint reedgrass [Calamagrostis canadensis (Michx.) Nutt.] were determined from 1986 to 1989 near Delta Junction, AK. Applications were made 2 wk apart from late May or early June to September. Glyphosate did not provide control before June 15 or after September 1. Bluejoint reedgrass was controlled best when glyphosate was applied from late July to mid-August. Ammonium sulfate (2.2 kg ha-1) or nonionic surfactant (0.5% v/v) increased control except on the earliest and latest application dates. Control was consistently better with 1.1 than 0.6 kg ha-1 (ai) of the isopropylamine salt of glyphosate.