UBC Theses and Dissertations
The biology and control of some turf weeds. Ho, Lee San
This study of some common turf weeds of the Vancouver area considers some aspects of biology and control. Seed production observations indicated that seeds ranging from 300 to over 260,000 per plant were produced each season by different species. Seeds of Senecio vulgaris L., Sonchus oleraceus L. and Hypochaeris radicata L. germinated immediately after harvest while others required several months. H. radicata showed good germination in light while Cerastium vulgatum L. and Lamium amplexicaule L. germinated best in a shaded or dark environment. Two germination peaks in spring and fall occur in this group of turf weeds. However Stellaria media (L.) Cyrill produced flowers and seed for most of the year. Rumex acetosella L. also had a long flowering period as did Plantago lanceolata L. and P. major L. The three latter species were found to require a long time to mature in the flower head and so were not shedding seed over the considerable period of time characteristic of S. media. Leaf area development did not appear to be associated with root development in the seedling weeds examined, and variations in the relative leaf areas of the different species occurred with time. Marked differences in flowering period and characteristics were apparent in observations on the various weeds made over a 17 month period. Apomictic seeds of Taraxacum officinale L. were found to have a germination rate significantly lower than those produced by artificial pollination. Inhibitory materials present in leaves and stems of weeds were shown to delay germination of bent grass nearly three weeks and to definitely reduce the percentage germination. The species showing the greatest inhibitory properties were Matricaria matricarioides (Less.) Porter, S. media and P. lanceolata in that order. Four turf grasses were shown to differ in their responses to proprietory mixtures of the phenoxy type herbicides, and weed species similarly differed in their responses to the newer herbicides which included Banvel D (dicamba), Tordon, phenoxypropionic materials and mixtures containing two and three chemicals.
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