摘要:

Leaf rust of barley(Hordeum vulgareL.), caused byPuccinia hordeiOtth. is common in New Zealand. It is particularly prevalent in the Canterbury region of the South Island. In a virulence survey carried out between 1990 and 1993 to determine the extent of pathogenic variation in the population ofP. hordeiin New Zealand, four virulence patterns were detected amongst 187 isolates from barley. All isolates were virulent on the genesPa, Pa2, Pa4, Pa6, Pa9,andPa12,and avirulent onPa7.Eighteen, 10, and 99% of isolates were virulent on the genesPa3Pa5, and Pa8respectively. No isolates were virulent on the combination ofPa3andPa5It is postulated that the barley cultivar ‘Liberty’ relies on the genePa3for its resistance to leaf rust. This is the first record of virulence onPa3andPa12in New Zealand. The cultivars ‘Liberty’ and ‘Triumph’ (which containsPa12) provided selection pressure for the spread of pathotypes with these two virulences respectively.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513877

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The demethylation inhibiting (DMI) fungicides, tebuconazole and triadimenol, both of the triazole group, were evaluated for the control of white rot (Sclerotium cepivorumBerk.) on onion(Allium cepaL). Both fungicides, applied as foliar sprays, gave a high degree of white rot control, effecting reductions in disease of up to 85% ofthat in untreated plots. When applied as a soil surface spray immediately after sowing, tebuconazole provided a high level of protection all season. The greatest degree of control was obtained from a combination of seed treatment with procymidone (a dicarboximide fungicide), followed by foliar sprays of either procymidone, tebuconazole, or triadimenol. Tebuconazole was unsuitable for seed treatment, causing high seed and seedling mortality. For maximum control of white rot, a combination of seed treatment and foliar sprays should be used. The triazoles—tebuconazole and triadimenol are suitable alternatives to procymidone for foliar sprays.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513878

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Mating disruption of lightbrown apple moth (Epiphyas postvittana(Walker))was assessed in combination with reduced insecticide programmes covering 321 ha of trials in commercial Nelson apple (Malus domesticaBorkh.) orchards from 1990/91 to 1993/94. The aim was to compare insect control and insecticide residues under a combination of reduced insecticide plus pheromone, compared to the standard insecticide programme alone, on a commercial scale. The combination of the pheromone and two fewer spray applications post‐Christmas, including the omission of the final application 2 weeks before harvest, provided an equivalent level of leafroller control to the standard insecticide programme in 3 of the 4 years. Reduced insecticide use in the absence of pheromone had increased fruit damage. Individual sites where poor control was obtained with pheromone were characterised by a small treated area or poor application technique, indicated by trap catch inside the treated area. High rate pheromone (2000 dispensers/ha), yielded significantly less fruit damage at harvest than the standard pheromone rate (1000/ha). Azinphos‐methyl residues were reduced on fruit at harvest in the pheromone treatments, and the incidence of fruit with low or non‐detectable residues was increased. Prospects for managing leafrollers using pheromones in combination with reduced insecticide programmes are promising, although further work is needed to make this alternative more cost‐effective.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513879

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

An “eye‐spotted” beach ball and a commercially available deterrent eye‐spot ball significantly reduced the number of house sparrows(Passer domesticus)visiting a bird table to feed. The commercial ball had a greater deterrent effect than the beach ball at all four distances tested (10, 20, 30, and 40 m). The deterrent effect of both balls decreased with distance from the table, and was neglible at c. 40 m. Deterrence was increased 10% by illuminating the eyes with a rotating halogen light and by reinforcing the visual stimulus with alarm calls of blackbirds(Turdus merula),house sparrows, and starlings(Sturnus vulgaris),but declined with continuous use, and disappeared altogether after 9 days. Eye‐spot beach balls in a vineyard significantly reduced landings by song thrushes(Turdus philomelos)for 2 weeks, and landings by blackbirds, house sparrows, and starlings for 3 weeks. They failed, however, in the fourth week when the grapes were fully ripe and most in need of protection. Eye‐spot balls are environmentally friendly, so could be especially useful bird scarers in organic vineyards and near residential areas.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513880

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The increase in soluble solids concentration (SSC) during maturation of kiwifruit(Actinidia deliciosa(A. Chev.) C.F. Liang et A.R. Ferguson ‘Hayward') in 16 orchards of the eastern coastal plain of Corsica was analysed in relation to soil characteristics and climate data for 2 years (1987 and 1988). Even if time was expressed in degree days, a year‐to‐year difference in SSC evolution with time was observed. A smooth decrease in SSC in early October 1987 was noticed and may be the result of the high rainfall which occurred during that period. Using the 1988 data set, SSC increase was estimated as a function of time (under a quadratic form), total soil sand level, and the inverse of soil crude silt level, meaning that soil retention capacity probably influenced SSC increase. The derivative with respect to time of this function was also an acceptable estimate of observed rate of increase in SSC (RI). Observed RI, as well as calculated daily RI, increased as mean air temperature decreased, as reported in other papers. These equations were then tested on the 1987 data set and were also good estimates of SSC and RI except during the high rainfall period. However, the relation between RI and mean temperature was not consistent in 1987 since, in late October, increasing RI were observed with increasing temperature. This suggests that increasing SSC during maturation may not only be the result of starch hydrolysis but more probably the balance between complex physiological processes.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513881

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Net photosynthetic rate, adaptation, compensating and saturating irradiances, mitochondrial respiration rate in the dark, photo‐respiration rate, CO2‐compensation concentration, assimilation number, and quantum yield were evaluated on both male and female kiwifruit (Actinidia deliciosa(A. Chev) C.F. Liang et A.R. Ferguson) leaves. Specific leaf mass, specific leaf area, and chlorophyll content were also estimated. Statistically higher values of the net photosynthetic rate, saturating irradiance, and photosynthetic productivity were observed in the leaves of generative shoots of the female plants.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513882

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The afternoon decline in the collection of kiwifruit (Actinidia deliciosa(A. Chev.) C.F. Liang et A.R. Ferguson var.deliciosa) pollen by honey bees (Apis melliferaL.) was investigated. Most staminate and pistillate flowers open before the time of anther dehiscence. Flowers of both sexes partially close again in the late afternoon of the day that they first open and make more pollen available after anther dehiscence. Staminate flowers make most of their pollen available in the morning and early afternoon. Most of the bees that stopped collecting kiwifruit pollen in the early afternoon remained in the hive without being recruited to other food sources. Pollen availability from staminate flowers in an orchard with normal numbers of foraging bees reached a peak between 1000 and 1100 h, and then dropped sharply until 1300 h after which time it remained constant. The availability of pollen from staminate flowers in an orchard with few foraging bees continued to increase from the time of anther dehiscence until the late afternoon. This suggests that the decline in pollen collection is the result of the pollen supply becoming depleted and not because it becomes dry and difficult to collect.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513883

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Matching crops to climate is an important activity for planning production. Three important climatic factors were identified as being important determinants of kiwifruit(Actinidia deliciosa’Hayward’ (A. Chev) C.F. Liang et A.R. Ferguson) distribution: winter chilling; growing season thermal time; and annual rainfall. Indices for each of these factors were developed to enable mapping of the most suitable areas for kiwifruit production. These were May‐July temperatures of 11°C or less as the optimal winter chilling requirement, a thermal time accumulation of 1100 degree‐days above 10°C from October to April, and an annual rainfall of 1250 mm or more. Apart from Northland, all the traditional areas of kiwifruit production have a suitable climate. However, there are substantial areas of inland Bay of Plenty to Rotorua, the Waikato, north Taranaki, and northern Hawke's Bay where the climatic requirements are also satisfied. A high frequency of extreme winds may be an additional limiting factor in some of these regions, such as Taranaki. The total area of suitability is enlarged if irrigation is available, particularly in the southern North Island and central Marlborough. Within this climatic range the estimated dates for the average end of dormancy and 50% flowering are spread over 4 weeks, and estimated budburst dates over 11 days. Although use of average climate data to describe kiwifruit distribution provides a valuable first‐order assessment, it would be desirable to incorporate analyses of climate variability in future studies of this kind.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513884

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The incidence and severity of bud loss as a result of the floral bud disorders collectively called “budjump”, were investigated from 1986 to 1991 throughout the Waikato region of New Zealand. Large variation was found in levels of bud loss from year to year. Most bud loss was found in the cultivar ‘Hosui’, with high levels of bud loss significantly reducing fruit production in some years. In the cultivars ‘Kosui’, ‘Shinsui’, ‘Nijisseiki’, and ‘Shinseiki’ bud loss was much less severe. On ‘Hosui’ most bud loss was found on young trees, and on young wood on older trees. Least bud loss was found at branch tips and on spur buds on older wood. High levels of bud loss were also associated with reduced flower numbers in remaining flower clusters. The type of rootstock and training system used had no effect on the incidence of budjump.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513885

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The influence of wood age on floral bud distribution was investigated on the nashi (Pyrus serotinaRehder var.cultaRehder) cultivars ‘Hosui’, ‘Kosui’, ‘Nijisseiki’, and ‘Shinsui’ at 3, 6, and 9 years of age. Comparisons were made between each cultivar grown on either pergola, Y‐frame, or centre‐leader training systems. Floral bud numbers were noted for both spur and lateral sites, and at shoot tips. In all cultivars, most floral buds were produced on young wood. This was especially marked for the lateral‐bearing cultivars ‘Hosui’, ‘Kosui’, and ‘Shinsui’. Bud development on ‘Nijisseiki’ was more evenly distributed over all wood ages, with a significantly higher proportion of spurs. Spur production was lowest in ‘Kosui’. Tree growth was most vigorous on Y‐frame and least vigorous on pergola systems, but training systems did not consistently affect the mix of wood ages or bud development. All cultivar/training system combinations showed a changing pattern of wood age and floral bud distribution over time. From 6–9 years of age the proportion of 1–2‐year‐old wood declined especially rapidly on ‘Hosui’ and ‘Kosui’, placing increased reliance on bud development from older wood and on spurs.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513886

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor