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Acetyl-coenzyme A carboxylase (ACCase) inhibitors such as haloxyfop, pinoxaden and clethodim selectively control grass weed species in many types of crop. Here, we characterised two populations of ...

Intensive winter forage grazing systems have a high risk of environmental impact due to nitrate leaching from urine deposition on cool, wet, fallow soils. We investigated the effect of sowing two catch crops after simulated winter forage grazing on kale to potentially reduce N leaching losses from a winter application of labelled 15N-urine (350 and 700 kg N ha−1) using field lysimeters. The experiment measured the capture of N by the sowing at recommended dates of either oats (Avena sativa) or Italian (It.) ryegrass (Lolium multiflorum) and the resulting 15N balance. Results showed that the sowing of an oats catch crop reduced nitrate leaching by 25% over the critical winter–spring drainage period compared with It. ryegrass. Relatively small amounts of the labelled 1⁵N-urine (3–4%) were captured in the catch crops of urine treatments so the reduced nitrate leaching under the oats crop was attributed to lower drainage over the period.

The contamination of a perennial ryegrass (Lolium perenne) dairy pasture infected with a novel endophyte with other ryegrass/endophyte associations was studied over 2 years in Hamilton, New Zealand. Five management treatments (turnip crop, usual rotational grazing, usual rotational grazing followed by topping, silage making, hay making) were applied to produce a range of natural reseeding levels, and then three establishment methods (spray/cultivation, double‐spray/fallow, hard‐grazing) were used before drilling AR1 endophyte‐infected perennial ryegrass (no lolitrem B or ergovaline production). Contamination from wild endophyte (Neotyphodium lolii)‐infected perennial ryegrass, endophyte‐free perennial ryegrass, wild endophyte‐infected hybrid (L. boucheanum syn. L. hybridum)/Italian ryegrass (L. multiflorum), N. occultans endophyte‐infected hybrid/Italian ryegrass and endophyte‐free hybrid/Italian ryegrass tillers was determined. Contamination was assessed in the two summers following the autumn (...

In certified organic cropping systems, the supply of nitrogen (N) to crops is limited by restrictions on fertiliser inputs, although green manure crops can be used to improve N retention and supply. This study involved a comparison between three green manure crops (oats (Avena sativa), lupins (Lupinus angustifolius), and oats‐lupins mix) and a fallow for their ability to conserve N over winter and influence N availability to a subsequent crop. Intact soil monolith lysimeters (19 cm diameter × 30 cm deep) were taken from an established organic farm and the experiment included four replicates of the three green manure crops and a fallow treatment. Nitrate‐N leaching losses from the various treatments were measured over a 150‐day period (March‐October). The green manure crops reduced the amount of N that was leached over winter. Cumulative N leaching losses were similar from the three green manure treatments (4.1–4.9 kg N ha‐1), and these were significantly lower than N loss from the fallow treatmen...

Two trials were performed to study the effect of nitrogen fertilisation on prairie grass (Bromus catharticus) sward characteristics, and to compare the agronomic performance of this species with that of Italian ryegrass (Lolium multiflorum). Both trials were carried out in the Humid Pampa in Argentina. In both trials, annual herbage accumulation depicted a linear model with increasing nitrogen levels. Increases in tiller population densities due to nitrogen fertilisation were more evident in late winter. Tiller categories and sward components were relatively unaffected by nitrogen fertilisation. Until mid spring, prairie grass and Italian ryegrass accumulated similar total herbage masses, but Italian ryegrass exhibited earlier growth than prairie grass and the latter was superior from late spring onwards. Dry matter digestibility was higher in Italian ryegrass than in prairie grass from early to mid spring. It was concluded that prairie grass could be a complementary annual crop in the Humid Pamp...

Milk production from cows grazing existing perennial ryegrass pastures or those direct‐drilled with Italian ryegrass (Lolium multiflorum Lam. cv. Concord) or with new perennial ryegrasses (Lolium perenne L.) was measured over the 1991/ 92 and 1992/93 lactations (July‐April), on intensively managed farmlets. This trial complemented large‐plot grazing experiments, and incorporated similar renovation methods of direct‐drilling (undersowing) and herbicide application before direct‐drilling of grass seed. Twenty Friesian cows rotationally grazed each of the three treatment farmlets; they were milked from July/August until April/May. Average herbage accumulation in late winter/early spring on the Concord farmlet was only slightly greater (+100 kg DM/ha), but in summer/autumn was inferior (‐350 kg DM/ha) to herbage accumulation on the unrenovated perennial ryegrass‐based farmlet (Control). In winter/spring (July‐December) 1991 and 1992, cows on the Concord farmlet produced similar milk yields (about 280...

A spaced plant trial, a small plot trial, and a field trial evaluated an endophyte (Acremonium spp.) (AR6) which does not produce lolitrem B in the tetraploid cultivars Grasslands Moata (Lolium multiflorum) and Grasslands Greenstone (L. multiflorum × perenne), and in the perennial cultivars (L. perenne) Grasslands Pacific and Grasslands Nui. The endophyte was compared to three lolitrem‐producing isolates viz. AR41, Waiau, and the wildtype. In all trials Argentine stem weevil (ASW) (Listronotus bonariensis) adult feeding, oviposition, and larval damage were recorded at regular intervals between October and March. ASW attack was highest on the tetraploid cultivars, Greenstone and Moata. In most instances, all endophytes reduced adult ASW feeding and oviposition in the different cultivars compared with their respective endophyte‐free (E‐) controls. Feeding and oviposition on endophyte‐infected (E+) Moata and Greenstone was in some instances similar to, or higher than, that on E‐ Nui or Pacific. All ...

Three Italian and four hybrid ryegrass cultivars (Lolium multiflorum and L. boucheanum Syn. L. hybridum) sown with the white clover cultivar Grasslands Huia (Trifolium repens), were evaluated under frequent/hard grazing or infrequent/ lax grazing. Dry matter (DM) yields and species composition were assessed for 5½ years. Ryegrass tiller and white clover growing point population densities were determined annually, and leafrstem ratios every spring and autumn. Ryegrass tillers were assessed for infection with an Acremonium‐like endophytic fungus and bacterial wilt disease (Xanthomonas campestris pv. graminis). The Italian ryegrass cultivars Moata and Concord had total yields 33% greater than the mean of the other cultivars (1800 kg DM/ha) over the first autumn and winter. The Italian cultivars persisted well for 3 years, except Concord which had a high incidence (34%) of bacterial wilt. Of the hybrid ryegrasses, cultivar Corvette had high ryegrass yields in the first year (9800 kg DM/ha), similar t...

The susceptibility of Italian ryegrasses (Lolium multiflorum Lam.) to Argentine stem weevil (Listronotus bonariensis (Kuschel)) was investigated in laboratory feeding and oviposition experiments, and in a field trial. Some Italian ryegrasses (for example, ‘Concord’, ‘Corvette’, ‘Progrow’) are infected with an Acremonium-like endophytic fungus. The presence of Acremonium-like endophyte did not deter or reduce adult Argentine stem weevil feeding or oviposition. The introduction of Acremoniun lolii Latch, Christensen&Samuels endophyte isolated from perennial ryegrass (L. perenne L.) into L. multiflorum conferred resistance to L. multiflorum from Argentine stem weevil feeding. Lolitrem B (a tremorgenic mycotoxin) concentrations ranged from 0.2 to 4.50 μμ/g and from 0.01 to 0.09 μμ/g dry weight of grass in A. lolii-infected and Acremonium-like infected L. multiflorum, respectively. This indicates that the level of insect and animal feeding deterrents and toxins are dependent on the species of endophyt...

Ryegrass mosaic potyvirus was identified, using immune serum electron microscopy, at one site near Dunedin, New Zealand. A mite infesting the infected Lolium multiflorum Lam. plants was identified as Abacarus hystrix (Nal.), the vector of RyMV. A commercially available monoclonal antibody which detects a group-specific epitope on aphid-transmitted potyvirus capsids was used successfully to detect RyMV in immunoblots using polyvinylidene difluoride (but not nitrocellulose) membranes.

Carbohydrate was measured in tissues of‘Grasslands Tama’ Westerwolds ryegrass (Lolium multiflorum Lam.) at weekly intervals during winter in Canterbury. Percentage of soluble carbohydrate in herbage was high (to 33% of DM); it was higher in stubble (to 47% of DM) than in leaf (to 27% of DM) and was low in roots (less than 11% of DM). Concentrations of soluble carbohydrate fluctuated more in stubble than in leaf tissue and roots. Most of the soluble carbohydrate in leaves was simple sugars, but was fructosan or fructosan-like compounds in the stubble and roots. In a generally dull, cold period in August, the soluble carbohydrate content of stubble, principally the simple sugars, fell markedly.

415 ryegrass genotypes, collected from pastures on soils of different exchangeable magnesium concentration, together with 160 genotypes from 8 commercial cultivars were examined for variation in herbage magnesium concentration. There was no evidence for ecotypic or cultivar differences in magnesium concentration, but there was substantial variation within all populations. Magnesium concentrations up to 0.552% of DM were found. When a high magnesium selection of perennial ryegrass was tested further, indications of genetic control of herbage magnesium concentrations were obtained. Within this selection there were positive correlations between cOl1centrations of magnesium and potassium, calcium, iron, copper, manganese, and zinc, but a significant negative correlation with sodium. It is concluded that there is scope for selection of high-magnesium ryegrass, but sodium content would have to be monitored.

Plots in a grazed trial in which 4 ryegrass cultivars received regular insecticidal applications of oxamyl were sampled at about 2-month intervals from September 1981 to May 1983 and generic nematode populations assessed. Significant treatment, sampling time, block, and cultivar effects were found. Oxamyl reduced most nematode populations, including Heterodera, Meloidogyne, Heticotylenchus, Paratylenchus, and Pungentus, possibly contributing to increased herbage production and influencing sward composition. The greatest cultivar effect was depression qf Paratylenchus beneath the low-yielding ‘Grasslands Manawa’. There was no evidence of nematodes developing tolerance to oxamyl, and population reduction occurred to 90 cm depth.

The banding pattern of seed storage proteins resulting from sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) of extracts from bulked seed samples has been used to distinguish species and cultivars within the genera Lotium and Festuca. Perennial (L. perenne L.) and Italian (L. multiflorum Lam.) ryegrasses were readily differentiated, and distinctive banding patterns were obtained for seed proteins from a range of cultivars and varieties of each, some very closely related. These patterns were independent of site, year, or generation of seed production. Fescue species differentiated were F. pratensis Huds. (meadow fescue), F. arundinacea Schreb. (tall fescue), and F. rubra L. (creeping red and Chewings fescues). The 2 types within F. rubra could be distinguished. SDS-PAGE of bulked seed samples offers a rapid method for distinguishing cultivars of Lotium and Festuca during seed certification, for checking for genetic shift or contamination in cultivars d.u~ng seed multiplication,...

The effect of seedling density and cutting intensity on components of floret production in Manawa ryegrass was investigated. Correlations between floret production, pre-flowering tillering, aftermath tillering, and awning were examined in relation to the hypothesis that genotypes tending towards L. multiflorum are increased during seed multiplication. Decreasing density markedly increased inflorescence number/plant and increased florets/spikelet, but decreased spikelets/inflorescence. Lenient cutting increased inflorescence number/plant and spikelets/ inflorescence, but produced a compensatory decrease in florets/spikelet. Plants producing the greatest number of florets were those with the greatest number of tillers in the pre-flowering stage, but which showed the greatest decline of tillering after floret harvest. This implied that genotypes with growth patterns tending towards L. multiflorum would have increased in the seed population, but the observation that strongly awned plants produced few...

Ramularia pusilla Ung. was recorded on the following grasses in New Zealand:—Agrostis gigantea L., Agrostis stolonifera L., Agrostis tenuis Sibth., Anthoxanthum odoratum L., Bromus catharticus Vahl., Lolium multiflorum Lam., Lolium perenne L., Lolium perenne L. × Lolium multiflorum Lam., Lolium multiflorum Lam. × Festuca gigantea Vill., Lolium perenne L. × Festuca arundinacea Schreb., Festuca rubra L. subsp. commutata Gaud., and Poa annua L. Leaf symptoms were of the eyespot type and the dimensions of conidia in these lesions varied according to the host. Growth of all isolates on agar media was of the staling type but varied greatly in the amount of growth, colour of colony, and in the pigments secreted. Cross-inoculation studies showed that many of the isolates were capable of varying degrees of cross-infection. Isolates from the Agrostis spp. had closely related host ranges, as also did isolates from the Lolium spp. and Lolium × Festuca hybrids. Lesions caused by R. pusilla were found througho...

Established plots of 10 different pasture species were trodden at different rates nine times between December 1958 and October 1959, with mature Romney sheep. Treading generally reduced measured herbage yield, the heaviest treading causing the greatest reduction. Reduction in tiller number appeared to be the main cause of the reductions in yield. Under heavy treading, plant tolerance order, from most to least, was: perennial ryegrass (Lolium perenne L.), Poa pratensis L., Poa trivialis L., short-rotation ryegrass (Lolium perenne L. × Lolium multiflorum Lam.), browntop (Agrostis tenuis), white clover (Trifolium repens L.), timothy (Phleum pratense L.), cocksfoot (Dactylis glomerata L.), red clover (Trifolium pratense L.), and Yorkshire fog (Holcus lanatus L.). Under moderate treading the order was P. trivialis, perennial ryegrass, P. pratensis, short-rotation ryegrass, white clover, timothy, browntop, cocksfoot, red clover, and Yorkshire fog.

The new herbage cultivarCeresProgrow is described. It is a diploid Westerwolds ryegrass, selected from a pasture in Marlborough, containing the annual ryegrass endophyte.