The ability to spread underground through rhizomes, retention of a strong tap-root and a reputation for pest and disease tolerance, make caucasian clover (Trifolium ambiguum Bieb.) (CC) an attractive possibility for improving legume performance in coastal Bay of Plenty dryland dairying pasture. Large plots (0.125 ha) of Grasslands Kopu white clover (T. repens) (WC) and Endura CC were sown in spring (September 1994) as pure species swards following maize cropping and all but one 7 m wide strip undersown with ryegrass (Lolium perenne) in the following winter (July 1995). From September 1995, subplots within pure clover and undersown areas were treated with nematicide (oxamyl, fenamifos) and fungicide (metalaxyl, prochloraz) and mown to coincide with dairy cow grazing for determination of herbage yield. By the second spring, growth rates of CC matched those of WC and were superior by up to 60% through the second summer resulting in 9% greater total yield for CC pastures. Accumulated yield of CC pasture from September 1995 to June 1996 was significantly greater than WC (11.8 and 10.9 t DM/ha respectively). Caucasian clover was less responsive than WC to nematicide and fungicide treatment. With the methods used, CC can be established and perform well by the second year under dairy grazing in warm northern regions, and may provide for better summer production than WC. No difference was observed between the clover species in acceptability or pasture utilisation by dairy cows. Keywords: dryland dairying, northern New Zealand, pasture establishment, pasture growth, pesticide responses, Trifolium ambiguum, Trifolium repens

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In a year of spring-summer drought on a sandy volcanic ash soil, ryegrass/caucasian clover (RG/ CC) and RG/white clover (RG/WC) pastures had similar rapid increases in pasture growth rates during September. Growth rates peaked around 25 October (65-70 kg DM/ha/day) for RG/CC and around 14 October (50-60 kg DM/ha/day) for RG/ WC. As drought intensified the declines in pasture growth rates were similar, but delayed by up to 3 weeks for RG/CC. Both pastures reached minimum summer growth rates of

Caucasian clover (CC) and white clover (WC) pastures were established on a Bay of Plenty dairy farm in September 1994 and undersown with ryegrass (RG) in July 1995. Yields of mown RG- CC plots surpassed those of RG-WC plots from December to April in the second year after establishment (1995/96), producing 1362 kg (26%) extra DM/ha during this period. In 1996/97 yields of RG-CC plots surpassed those of RG-WC from October to April, producing 1531 kg (43%) extra DM/ha in December-April. In grazed RG-CC plots during December-May 1996/97, RG yields were slightly reduced (371 kg/ha, -12%) in comparison with RG-WC plots, and extra production resulted from greatly increased total legume yield (2155 kg/ha, 187%). Pasture legume content during summer-autumn averaged 24% for RG-WC and 54% for the RG-CC pastures. The superior performance of CC over WC appeared to relate to its protected underground growing points, and taproot retention, facilitating better pasture cover during summer, and greater tolerance of pests including grass grub and clover cyst nematode. Caucasian clover shows promise as a perennial legume which may offer improved availability of high quality forage at a time of year when clover growth is often insufficient for good animal performance. Caucasian clover clearly has potential in northern as well as southern regions of New Zealand. Keywords: dairy pasture, Lolium perenne, northern New Zealand, pasture pests, Trifolium ambiguum, Trifolium repens

Pasture plots containing white and Caucasian clover were established on a summer-dry coastal Bay of Plenty farm and maintained under dairy grazing into a second year. Of soil dwelling pests, grass grub and Tasmanian grass grub populations increased most rapidly, with fewer present under Caucasian clover. Foliar insect feeding, with up to 26% loss of leaf area in white clover, was caused by lepidopteran larvae of Zizina labradus and indigenous species of Epyaxa. Epyaxa rosearia was the most significant defoliating insect on Caucasian clover. This is the first time that Epyaxa has been implicated as a pest of pasture legumes.