Kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferguson var. deliciosa) plants were subjected to controlled advective frosts in the autumn, winter, or spring and injury symptoms were recorded. The plants naturally hardened in autumn and early winter and rapidly dehardened in spring; temperatures lower than -5, -7, -6.5, and -OSC respectively in May, June, July, and September caused injury to plants of 'Hayward' cultivar, and all plants in the test population were killed at temperatures below -9°C in May and 67% were killed at -13°C in June. With respect to damage incidence and subsequent bud break, plants of'Bruno' cultivar appeared to be slightly less frost tolerant than 'Hayward' plants in May and in June but these cultivar differences were minor.

Seed yields of ryegrass and tall fescue have increased rapidly over the last seven years; the best farm yields are now reaching 3000 kg/ha, up from 2000 kg/ha. These increases are largely due to the adoption of technologies developed from research funded from grower crop levies and effective technology transfer programmes. The key technologies are (1) the adoption of trinexapac ethyl (TE), a plant growth regulator that blocks gibberellic acid biosynthesis and reduces lodging; and (2) new generation triazole and strobilurin fungicides that give improved disease control and extend the period that green leaf area is maintained on crops. Seed yield data from 10 ryegrass and 6 tall fescue trials with TE, and from 13 fungicide trials are presented. The average seed yield increase in tall fescue treated with 200 g TE/ha and ryegrass with 400 g TE/ha was 67% and 50% respectively. In fungicide trials, seed yields in forage perennial ryegrass were increased by 20% and in turf ryegrass by 42%. A survey of growers indicated 95% of ryegrass growers and 100% of tall fescue growers had adopted the use of TE three years after the commercial release of the product. Keywords: fungicides, plant growth regulators, ryegrass, seed yield, strobilurin, tall fescue, triazole, trinexapac

Context Bird damage to horticultural crops causes significant economic losses for growers around the globe. However, bird damage is unpredictable and pest-bird movements and abundance patterns are poorly understood. Aims To assess whether habitat management is likely to be an effective approach for controlling two pest-bird species (house sparrow, Passer domesticus, and greenfinch, Carduelis chloris) in New Zealand’s arable landscape. Methods Breeding- and winter-bird and habitat surveys were carried out over a 3-year period (2003–05) on 19 1-km × 1-km squares with arable crops on the Canterbury Plains, New Zealand. Bird abundance and/or distribution were analysed with respect to both temporal and spatial (crop- and boundary-habitat composition) variables. Results Estimated breeding-season densities for house sparrow were higher but more stable than those for greenfinch (which increased by 70% over a 3-year period), and for individual farms were more predictable across years than were winter densities. Boundary habitat was the best predictor of bird densities and distribution in the breeding season; features associated with enhanced seed abundance or access were important in the winter. However, habitat composition alone could not account for temporal and spatial variation in bird densities on farms. Conclusions Either habitat management or the reduction of key seed resources could potentially control pest-bird numbers. However, habitat management is likely to have adverse consequences for other important functions (such as the shelter and biodiversity benefits of shelterbelts), and any form of bird control applied at the farm scale is unlikely to be effective. Implications To make control actions both effective and economically viable, a coordinated program involving multiple farms is likely to be needed. We recommend investigating the effectiveness of an experimental manipulation of key food resources at the landscape scale.

No abstract

Fish-tail oxalis (Oxalis latifolia) and pink bindweed (Calystegia sepium) are problem perennial weeds in maize crops. Four field trials were conducted over two growing seasons to evaluate both cultural and chemical control methods. The post-emergence application of nicosulfuron provided good control of fish-tail oxalis, as did imazethapyr/imazapyr in imidazolinone-tolerant maize. Use of maize cultivars with strong early season growth or long "staygreen" attributes did not provide the expected reduction in oxalis bulb production. Two trials with pink bindweed showed that the post-emergence herbicides, nicosulfuron, dicamba and imazethapyr/imazapyr gave good control of this weed. Post-harvest crop management with stubble mulching, cultivation or glyphosate treatment had little effect on pink bindweed but use of glyphosate as close as possible to maize planting significantly reduced the bindweed population.