Yellow bristle grass (Setaria pumila) is a summer growing annual grass with a C4 photosynthetic pathway. It is now becoming a serious weed in pasture where it is highly competitive with perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) and is avoided by stock when at the seed head stage. On severely infested farms, it is estimated to cause production losses in the order of $100 000/100 ha unit, mostly due to stock not grazing areas where the yellow bristle grass is seeding. Keywords: yellow bristle grass, Setaria pumila, pasture, grass weed

The wild type of broom corn millet (Panicum miliaceum) is a serious emerging weed currently prevalent in New Zealand sweet corn (Zea mays) crops This study shows its seed is nearly twice the weight of other common grass weeds and can germinate in the temperature range 1634C with 50 germination at 26C and greatest germination occurring at 31C At 15C it took 8 days for seedlings to emerge but required only 4 days at 25C Seed was able to emerge from depths of up to 170 mm in a range of soils Experiments showed that broom corn millet seed can persist in the soil for longer than 2 years in the field but is killed in silage stack and bales Immersion in stock effluent for up to three months reduced seed germination to less than 40 These characteristics are discussed in relation to herbicide and management control options for this weed

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Field horsetail is a perennial rhizomatous weed with summergrowing fernlike foliage and sporelating stems It likes moist freedraining sandy soils and gravel riverbeds and flood plains Glasshouse experiments on 10month old potted field horsetail plants showed excellent efficacy of imazapyr amitrole metsulfuron picloram and combinations of picloram with metsulfuron or triclopyr all at highest recommended rates However in the field trial single applications of these herbicides did not provide effective longterm control with significant regrowth 2 months after treatment This suggests that most of the herbicide treatments did not damage the extensive root system sufficiently to stop considerable regrowth with herbicides such as triclopyrpicloram glyphosate and metsulfuron failing to give adequate control of this weed in the field Further applications of amitrole or triclopyrmetsulfuron 2 months after the initial treatment gave better results but also killed all other vegetation

Tutsan (Hypericum androsaemum) is a highly invasive semievergreen shrubby weed found throughout New Zealand Described as a serious pasture weed in 1937 it has been held in check for many years by tutsan rust Recently it has spread rapidly into pasture forestry and conservation areas Present methods available for managing tutsan are proving inadequate and unsustainable This review paper provides an overview of tutsans biology ecology habitat and its current distribution in New Zealand It details possible management strategies and control options with emphasis on control by herbicides The paper identifies a number of potential herbicides which although not currently registered for control of tutsan have shown good efficacy on this weed and could be developed for use on agricultural land through further research Herbicides currently registered for control of tutsan in Australia as well as the current recommendations in Victoria and Western Australia are also summarised