摘要:

Mated pairs ofEpiphyas postvittanaandPlanotortrix octowere marked and released at a point source in a young, 40 ha orchard. Port wine bait traps and pheromone traps along eight radiating transects were checked daily. In 1988, recapture ofE. postvittanawas 0.24% of females in bait traps, 0.23% of males in bait traps, with 3.4% of males in pheromone traps. In 1990, recapture of both male and femaleE. postvittanawas more successful (12.2% of females in bait traps, 4.4% of males in bait traps, and 12.4% of males in pheromone traps). No marked males and only one marked femaleP. octowere recaptured in bait traps, although 5.1% of males were recaptured in pheromone traps. The maximum dispersal distance recorded forE. postvittanamales was 600 m, but 80% of released males were recaptured within 100 m. For femaleE. postvittana, the maximum distance recorded was 275 m, with 99% dispersing 100 m or less. MaleP. octoexhibited similar dispersal capability to maleE. postvittana, with a maximum of 400 m recorded. Wild male and femaleE. postvittanawere very abundant, with 4629 males caught in pheromone traps and 615 males caught in bait traps, with 948 females caught in bait traps.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513831

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Ancistrocerus gazella(Panzer 1798) was found to prey almost exclusively on caterpillars of the lepidopterous family Tortricidae. This family includes New Zealand's most damaging pests of fruit crops—the leafroller mothsPlanotortrix octo, P. excessana, Ctenopseustis obliquana, C. herana, andEpiphyas postvittana. In Central Otago, A.gazellais limited primarily by an absence of nesting sites. When artificial trap nests consisting of small holes bored through blocks of straight‐grained wood taped together in bundles of 4–64 traps, and larger compound nests consisting of blocks of wood through which 64 evenly‐spaced holes were drilled, were placed at a height of 1.5 m in orchards, fields, and open places where A.gazellaoccurred, the trap nests were filled with P.octo, P. excessana, C. obliquana, and E.postvittana(> 90% of prey) and much lower numbers of other Tortricidae. A 64‐hole nest was set up in the wild where A.gazellawas plentiful until all holes were filled, 18 days later, as indicated by plugs of mud across the nest entrances. At that stage, the nest was removed to an abandoned orchard in another locality. After the second generation A.gazellafemales emerged and mated, they filled a new nest placed beside the one in which they were raised with leafrollers from the fruit trees. Their old nest also was reused. It is suggested that A.gazellacan be used to control all pest leafroller species in New Zealand berry crops in integrated management systems, with reduced use of insecticides and in conjunction with sex phermone mating disruption techniques.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513832

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

To compete in world markets, New Zealand's horticultural industries must meet increasingly stringent quality standards and market preferences, and continue to offer new and innovative products. Their ability to do this depends on the continual transfer of new orchard management technologies from discipline‐based research programmes. “Orchard 2000” is a computerised decision support system designed to provide a standard framework for the encapsulation of horticultural science into decision support “tools” for orchardists. These decision support tools provide information which helps decision makers with specific management decisions. The framework incorporates an orchard database which stores details of orchard layout, weather, production, operation, and finances. The decision support tools share this database rather than having their own files, so data are stored in an easily accessible and non‐redundant form. These tools also have a consistent graphical user interface, reducing the learning time for new tools. Prototype decision supporttools for orchardists have been tested by trial groups of apple and kiwifruit growers, consultants, and agribusiness. The prototyping approach for tool development implies continued iterative refinement. An “open” software standard has been adopted to encourage third party development of decision support tools.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513833

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The incidence of apple scab (Venturia inaequalis) on apple fruit was estimated from December to March in orchards with different levels of leaf and fruit scab and under different fungicide programs. Twenty orchards were monitored at Batlow, NSW, Australia from 1990 to 1993. Moderate levels of primary infection in the 1990/91 season resulted in levels of leaf scab in December/ January, which varied from 0 to 6.2% (mean 0.8%), and fruit scab in December from 0 to 7.1% (mean 0.9%). Fruit scab incidence measured in March was 0.4% (after the normal practice of removal of fruit to increase remaining fruit size). A mean of 1.6 fungicide sprays were applied from January to March, with a range of 0–7 sprays. It is likely that infection criteria would have been met on three occasions during December‐March. No significant increase of scab occurred in seven orchards where no fungicides were applied over this period. In the 1991/92 season, a dry spring resulted in five infection periods, four of which were low severity. No leaf scab was detected in December. A mean of 0.02% fruit infection (range 0–0.2%) was detected in December. The mean level of fruit infection was 0.03 % in March. No fungicides were applied during January‐March in 12 orchards (mean 0.6, range 0–4 sprays) without any increase in scab. Infection criteria were met on only one occasion over this period. The spring of 1992/93 was wet, resulting in 13 primary infection periods from mid September to the end of November. A mean fruit scab incidence (after excluding three orchards with management problems) of 0.1% was recorded in December although leaf scab was only present in trace amounts. The mean fruit scab level in March was 0.2%. During January‐March a mean of 2.8 fungicide sprays were applied (range 0–7). No significant scab increase occurred in 17 orchards where fruit scab levels were low in December. In the two orchards where management problems resulted in failure to apply fungicides and one orchard where fungicide resistance occurred, fruit infection levels increased from December through the season, in the worst instance from 12.3 to 23.1%. Infection criteria were met on three occasions during December‐March. A combination of low levels of inoculum in December, arrived at by effective primary infection control, together with increasing fruit resistance reduces the risk of disease incidence increase during the second half of the season in districts where rainfall is low. Our results suggest that in orchards with low levels of inoculum, careful disease incidence monitoring should enable protective spraying for apple scab control to cease at the end of the primary infection season, with the benefit of reducing the amount of fungicide applied to apples.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513834

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Measurements of the timing and amount of budbreak and flowering in ‘Hayward’ kiwifruit were made over 4 years in six regions of New Zealand. There was a large variation in the vine attributes measured. The number of flowers produced/winter bud varied 5‐fold between the worst site‐year combination and the best. The time of 50% budbreak varied by 32 days and the time of 50% flowering by 25 days. The proportion of flowers on the distal (tip) two buds ranged in a single year from a low of 10% at one site to > 65% at another on canes which had an average of 21 buds. The number of flowers/winter bud is considered to be made up of four components: the proportion of budbreak, the proportion of floral buds, the number of inflorescences/floral bud, and the number of flowers/ inflorescence. The proportion of budbreak and the proportion of floral buds were found to be most important in determining the number of flowers produced/winter bud, and both of these components were significantly higher at the cooler, southern, sites. The vines measured in this survey were all chosen from a single block in a single orchard within each region, so between‐vine variation was minimised. Despite this, total between‐vine variation accounted for nearly 40% of the observed variance in the proportion of budbreak and about a quarter of the observed variance in the number of flowers/ winter bud and the proportion of floral buds. Differences between regions were significant for all vine attributes measured except the number of inflorescences/floral bud, with cooler sites generally breaking bud earlier and producing more flowers. When averaged over all 4 years, the number of flowers/winter bud was over twice as high at the coolest site than at the warmest, and budbreak occurred more than 3 weeks earlier. The proportion of flowers on the tip two buds varied from an average of < 17% at one site to > 50% at the warmest site. Year‐to‐year differences were generally not significant when averaged over all regions, except that flowering tended to be early or late at all sites in the same years. Year‐to‐year variation was however very important within each region. Over 50% of the variance in the number of inflorescences/ floral bud was the result of year‐to‐year variation, and over a third of the variance of the number of flowers/winter bud. At the warmest site, both the number of flowers/winter bud and the proportion of flowers borne by the tip two buds varied more than 2‐fold in consecutive years. It is this between‐season variation that is of major significance in orchard management. It is also important for the industry at large because of the need to organise transport, storage, and marketing on a region‐by‐region basis.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513835

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

One‐year‐old apple (Malus domesticaBorkh.) nursery trees of several cultivars on MM 106 and M 9a rootstock were sprayed once in early summer with benzyladenine (B A) followed by one, two, or three applications of gibberellin (GA4+7) either in 1989 or in 1990. In both years GA4+7applied at the same time or 2 weeks after a B A spray produced more branches and more total growth than controls. In 1990, but not 1989, GA4+7applied 2 weeks after BA stimulated more branches and more total branch length than when these chemicals were applied together. In 1990 multiple applications of GA4+7beginning 18 days after B A sprays induced the longest branches, most total branch growth, and greatest branch crotch angles than applications involving a single GA4+7plus B A spray. In addition in 1989, immature leaves were removed immediately beneath the growing tip on the main stem (LR) once in early summer and sprayed with or without GA4+72 weeks later. Leaf removal treatments did not affect branching.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513836

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Calibrated heat balance stem flow gauges were used to study the daily water use by Geraldton wax (Chamelaucium uncinatumSchauer), a plant endemic to the coastal sand plains north of Perth, Western Australia. Sap flow was recorded for the trunk, primary and secondary branches, and partially shaded lower east and sun‐lit upper west branches in order to assess the influence of climatic variables, stem development, and exposure. Irradiance and leaf area strongly influenced diurnal sap flow. Sap flow in primary and secondary branches was comparable when expressed on a unit leaf area basis. Defoliation reduced water use of the secondary branch. Shedding of leaves under water stress, a common phenomenon in Geraldton wax, probably has similar effects. The level of internal shading influenced water use in the crown (1.2 and 1.5 kg/day per m2leaf area for branches with east and west exposure respectively). The difference in water use was prominent during the afternoon when the east branch was shaded. The results demonstrate the value of the heat balance stem flow gauges in measuring shrub water use directly.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513837

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Polysaccharides, sugars, and enzymes involved in starch metabolism were assayed at 14‐day intervals during development and the following 2 months of storage at 9°C for two New Zealand‐bred potato cultivars—'Ilam Hardy’ and ‘Rua’. Despite changes in sugars and activities of enzymes, starch levels remained relatively constant. Glucose and sucrose levels decreased throughout development. Enzymes involved in starch synthesis and degradation were active throughout tuber development. These observations suggest that the developing tuber may act as a dynamic pool of sugars available to the plant. Changes in sugars and enzyme activities between sampling dates reflected variations in soil temperature.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513838

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Postharvest rots and internal disorders of ‘Hass’ avocado (Persea americana) fruit develop during the latter stages of fruit ripening, with symptoms first appearing when fruit are minimally ripe but often becoming quite severe before the fruit are oversoft. Fruit ripened at 20°C and assessed at the same stage of ripeness, just before the flesh becomes oversoft, had fewer postharvest rots if they had been previously stored at 4 or 6°C, than if they had been stored at either lower or higher temperatures. Postharvest disorders increased with increased length of storage. Fruit failed to ripen properly at 30°C. Even at 25°C (a temperature typically experienced by fruit exported from New Zealand), the level of postharvest disorders was greater than in fruit ripened at 20°C. Best final quality was obtained with fruit coolstored at 6°C and then ripened at 15 °C. However, if fruit are to be ripened at c. 25°C, then final quality was better if the fruit were not coolstored but held at a temperature closer to the final ripening temperature. Fruit from a single orchard block, harvested, coolstored, and ripened together, individually reached minimum eating ripeness over an 8‐day period. Fruit which ripened earliest had the fewest disorders, with later ripening fruit typically having high levels of postharvest rots and internal browning.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513839

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The effects of hand pinching above node four on the main stem and the application of the plant growth regulators paclobutrazol and chlormequat chloride on seed production of field grown hybrid dahlia ‘Unwins Mixed’ were investigated over two seasons at the same site. Pinching reduced the spread of flowering and resulted in seed heads at approximately the same height above ground level because of the promotion of lateral branch length, but did not increase seed yield. Seed yield perplant was significantly increased following the application of chlormequat chloride at 1.5 kg a.i./ha at stem elongation in the first season, and by paclobutrazol applied at 1.0 kg a.i./ ha at the appearance of the first visible flower bud in both seasons, the former through the production of more seed heads/plant, and the latter through a significant increase in seeds/seed head in one season and seed heads/plant in the following season. Other seed yield components did not differ among treatments. Plant growth retarding effects were transitory and floral development and flower numbers were not altered by the plant growth regulators. Although results were inconsistent, chemical manipulation of this hybrid dahlia shows promise for seed production and warrants further investigation.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513840

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor