Investigations into glufosinate efficacy against Raphanus raphanistrum and Lolium rigidum / byAnuja Ruwanthi Kumaratilake.

Bibliography: leaves 125-141.xiii, 141 leaves : ill. ; 30 cm.Addresses the poor control of major weed species under southern Australian winter conditions by the non-selective post-emergence herbicide, glufosinate in order to determine the best way to use it. Dose response experiments were performed under simulated southern Australian winter conditions, and demonstrated a variable glufosinate efficacy between Lollium rigidum and Avis sterilis. Glutamine synthetase assays showed that target site sensitivity did not influence these results. Spray retention experiments showed no influence from plant size or morphological features, while metabolic studies showed that only a small proportion of glufosinate was metabolised in both species. Tests of several populations of Raphanus raphanistrum showed that all populations, despite geographical origin, were poorly controlled by glufosinate, in both field and simulated conditions. Experiments conducted at higher temperatures showed enhanced glufosinate efficiency. Experiments with the use of co-herbicides, chelating agents, fertilizer salts and hormones were also carried out. Studies on the effect of the pH of the herbicide solution on cell uptake showed that uptake into the cell wall only was enhanced by reducing the buffer pH. Shows that the poor efficacy of glufosinate against these species is mainly due to poor translocation of the herbicide.Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 200