RUST-INFECTED QUACKGRASS (ELYTRIGIA-REPENS) GROWTH AND RHIZOME BUD DEATH AFTER GLYPHOSATE APPLICATION

Photosynthesis decreased 32% in quackgrass infected with rust. Photoas similate transport in rust-infected quackgrass, assessed by autoradiog raphy, was less than that of control (no rust) leaves 35 min after exp osure to (CO2)-C-14. Greenhouse-grown quackgrass height, foliar and rh izome dry weights, rhizome length, and bud numbers decreased 11, 25, 2 8, 19, and 21% in rust-infected plants, respectively, compared to cont rol plants. Foliar and rhizome biomass decreased 31 and 39%, respectiv ely, in field-grown rust-infected plants. Rhizome bud death 48 h after treatment (HAT) in both control and rust-infected plants increased as glyphosate rate increased from 0.13 to 1 kg ae ha-1; however, control plant bud death was significantly greater than that of rust-infected plants.