scholarly journals Lesion development and conidial production of Neonectria ditissima on apple trees in four New Zealand regions

2019 ◽  
Vol 72 ◽  
pp. 123-134 ◽  
Author(s):  
Reiny W.A. Scheper ◽  
Lizelle Vorster ◽  
Lauren Turner ◽  
Rebecca E. Campbell ◽  
Kate Colhoun ◽  
...  
Keyword(s):  
New Zealand ◽  
Incubation Period ◽  
Climatic Factors ◽  
Lesion Length ◽  
Rain Event ◽  
Symptom Development ◽  
Conidial Production ◽  
Rainfall Frequency ◽  
Main Driver ◽  
Positive Controls

This study examined incubation period, lesion length and conidial release in Neonectria ditissima (European canker) in four New Zealand regions in relation to climatic factors. Incubation period was studied on potted ‘Royal Gala’ trees inoculated with N. ditissima. One week after inoculation, symptomless trees were dispatched to Waikato, Hawke’s Bay, Tasman, Otago and positive controls remained in a glasshouse. Conidial release was studied in trees with lesions that were dispatched to the same regions. Rain traps were placed under each lesion and conidia quantified after each rain event. Disease progress and conidial production were examined in relation to weather. Lesions developed significantly slower in Otago and faster in Waikato and the glasshouse, compared with Tasman and Hawke’s Bay. Symptom development accelerated with increasing daily hours of 11–16°C and humidity (74.6–87.2% RH). The highest conidium counts occurred in Waikato and the lowest in Otago, while conidial production started earlier in Tasman than elsewhere. Temperature is the main driver for symptom development during the incubation period and rainfall is not required. Rainfall frequency drives conidial production.

scholarly journals LETHAL ENCEPHALITOZOONOSIS IN CYCLOPHOSPHAMIDE-TREATED RABBITS

1999 ◽  
Vol 47 (1) ◽  
pp. 85-93 ◽  
Author(s):  
L'. Leng ◽  
M. Štefkovič ◽  
Viera Révajová ◽  
Halanová ◽  
M. Horváth
Keyword(s):  
New Zealand ◽  
Clinical Signs ◽  
Experimental Period ◽  
Peripheral Blood Cell ◽  
Negative Control ◽  
Blood Cell Count ◽  
Clinical Form ◽  
Experimental Animals ◽  
New Zealand Rabbits ◽  
Positive Controls

Encephalitozoonosis is an opportunistic infection in animals and humans. Its clinical form is observed in immunosuppressed hosts. We studied the occurrence of the manifest form of rabbit microsporidiosis under cyclophosphamide immunomodulation in 40 New Zealand rabbits. The experimental animals were intraperitoneally infected with 5 Ã 107Encephalitozoon cuniculispores. Two weeks after infection the animals were treated intraperitoneally with cyclophosphamide, first with 50 mg/kg and then with 15 mg/kg weekly during the 12-week experimental period. Positive controls were eitherE. cuniculi-infected or cyclophosphamide-immunosuppressed animals. The negative control rabbits remained untreated. Both clinical signs of encephalitozoonosis and depression of peripheral blood cell count developed between weeks 4 and 6 in the experimental animals which died during week 6 of the experiment. No clinical signs compatible with encephalitozoonosis were observed in any of the controls. The results suggest that immunosuppression induced by cyclophosphamide can give rise to a lethal form of encephalitozoonosis.

Climatic factors influencing New Zealand pasture resilience under scenarios of future climate change

2021 ◽  
Vol 17 ◽  
Author(s):  
Elizabeth Keller ◽  
Mark Lieffering ◽  
Jing Guo ◽  
W Troy Baisden ◽  
Anne-Gaelle Ausseil
Keyword(s):  
Climate Change ◽  
New Zealand ◽  
Climatic Factors ◽  
Early Spring ◽  
Future Climate ◽  
Future Climate Change ◽  
Fertilization Effect ◽  
Intensively Managed ◽  
Growing Conditions ◽  
Grazing Livestock

New Zealand’s intensively managed pastoral agricultural systems are vulnerable to climate change because of their dependence on grazing livestock and pasture as the primary feed supply. Drawing from recent modelling results, annual pasture yields in New Zealand are projected to be robust to a changing climate due to more favourable growing conditions in winter and early spring and increased plant efficiencies from the CO2 fertilization effect. However, growth is also expected to become more variable and unpredictable, particularly in water-limited regions. A combination of short-term, incremental changes (already part of current practice) and longer-term strategic interventions will be necessary to maintain consistent feed supply under future climate change.

scholarly journals Conidial production by Botryosphaeriaceae species from grapevine shoot lesions in Marlborough vineyards

2017 ◽  
Vol 70 ◽  
pp. 295-300 ◽  
Author(s):  
A. Shafi ◽  
H.J. Ridgway ◽  
M.V. Jaspers ◽  
E.E. Jones
Keyword(s):  
New Zealand ◽  
Environmental Conditions ◽  
Microscopic Observation ◽  
Dna Analysis ◽  
Sauvignon Blanc ◽  
Conidial Production ◽  
Air Temperatures ◽  
Botryosphaeriaceae Species

Botryosphaeriaceae species are important pathogens of grapevines so the effect of environmental conditions on sporulation from naturally infected Sauvignon blanc grapevines in two Marlborough vineyards was studied. Shoot lesions characteristic of Botryosphaeriaceae infection were marked on 24 grapevines in each vineyard for observation between September 2014 and April 2015. Pycnidia on the lesions oozed conidia during or soon after rainfall on five occasions at maximum air temperatures of 8.4—19.9˚C and relative humidities of 77—94.7%. Microscopic observation of the ooze showed conidia characteristic of either Neofusicoccum or Diplodia species in 67% and 50% of samples from Vineyard A and B, respectively. Sixty- nine colonies characteristic of Botryosphaeriaeae species were recovered after plating of conidial ooze and identified by DNA analysis as Diplodia mutila (39.1%), Neofusicoccum australe (30.4%), N. parvum (14.5%), N. luteum (5.8%), D. seriata (7.2%) and N. ribis (3.0%). All species have been reported previously as grapevine pathogens in New Zealand.

scholarly journals Documentary evidence of historical floods and extreme rainfall events in Sweden 1400–1800

2014 ◽  
Vol 11 (9) ◽  
pp. 10085-10116 ◽  
Author(s):  
D. Retsö
Keyword(s):  
18Th Century ◽  
Climatic Factors ◽  
Extreme Rainfall ◽  
Flood Frequency ◽  
Ice Age ◽  
Documentary Evidence ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Main Driver ◽  
Instrumental Period

Abstract. This article explores documentary evidence of floods and extreme rainfall events in Sweden in the pre-instrumental period (1400–1800). The survey shows that two subperiods can be considered as flood-rich, 1590–1670 and the early 18th century. The result is related to a low degree of human impact on hydrology during the period, and suggest that climatic factors, such as lower temperatures and increased precipitation connected to the so called Little Ice Age, should be considered as the main driver behind flood frequency and magnitude.

scholarly journals Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies

2012 ◽  
Vol 8 (3) ◽  
pp. 877-887 ◽  
Author(s):  
J. C. Stager ◽  
P. A. Mayewski ◽  
J. White ◽  
B. M. Chase ◽  
F. H. Neumann ◽  
...  
Keyword(s):  
South Africa ◽  
New Zealand ◽  
South America ◽  
Ocean Circulation ◽  
Climatic Factors ◽  
Global Climate Models ◽  
Meridional Overturning Circulation ◽  
Ice Age ◽  
Winter Rainfall ◽  
Future Warming

Abstract. The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ∼1400–1200 cal yr BP, decreased until ∼950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ∼600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming.

scholarly journals Production of Neofusicoccum species conidia and their pathogenicity on wounded and non-wounded blueberry shoots

2017 ◽  
Vol 70 ◽  
pp. 209-214 ◽  
Author(s):  
K.M.S. Tennakoon ◽  
H.J. Ridgway ◽  
M.V. Jaspers ◽  
E.E. Jones
Keyword(s):  
New Zealand ◽  
Relative Humidity ◽  
High Relative Humidity ◽  
Conidial Production

Pycnidial and conidial production by isolates of the four main Neofusicoccum species associated with blueberry in New Zealand was investigated. Pycnidia developed after 8 days on mycelial-inoculated detached green shoots. Conidial ooze was observed after further incubation for 12 h under high relative humidity at 25˚C. Numbers of oozing pycnidia and conidial numbers were generally low, but were significantly affected by isolate and species. Neofusicoccum ribis and N. parvum produced slightly more pycnidia and conidia compared with N. luteum and N. australe. Inoculation of non-wounded and wounded attached green shoots with either N. ribis or N. australe conidia showed that, 14 days after inoculation, lesions developed in wounded shoots only, with N. ribis (58.8 mm) producing longer lesions than N. australe (29.8 mm). Neofusicoccum ribis and N. australe were re-isolated beyond the lesion, with pathogen progression being significantly greater for wounded (47.1 mm) compared with non-wounded shoots (30.4 mm).

scholarly journals Path analysis: application in an epidemiological study of echinococcosis in New Zealand

1977 ◽  
Vol 78 (2) ◽  
pp. 135-149 ◽  
Author(s):  
M. J. Burridge ◽  
C. W. Schwabe ◽  
T. W. Pullum
Keyword(s):  
New Zealand ◽  
Path Analysis ◽  
Epidemiological Study ◽  
Climatic Factors ◽  
Animal Husbandry ◽  
Maximum Temperature ◽  
Causal Relationships ◽  
Analytical Technique ◽  
Additional Tool ◽  
Causal Pathways

SUMMARYThe method of path analysis is described in detail. Application of this analytical technique in the interpretation of causal relationships in complex biological systems is demonstrated using data from an epidemiological study of echinococcosis in New Zealand. The results identified the major causal pathways determining Echinococcus granulosus prevalence in dogs, based on multiple regression analysis of a linear causal model constructed from prior biological and epidemiological knowledge. Only ethnic and sheep husbandry variables had important direct effects on prevalence in the North Island of New Zealand, with some climatic factors (maximum temperature and relative humidity) and soil porosity acting indirectly through animal husbandry practices. It is suggested that path analysis, by permitting interaction between epidemiological theory and statistical analysis, provides a valuable additional tool to epidemiologists for the study of causal relationships among variables in multivariate systems.

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