Behavioral sensitivity to microwave irradiation

In "Behavioral sensitivity to microwave irradiation" by N. W. King et al. (23 Apr., p. 398), lines 1 to 8, coltumn 2, page 399, should read " basis of the level of focusing current used to control and monitor the output power of the magnetron (25). A shift from zero to a present level of available power in the exposure cavity was accomplished by applying 5 kv of 60-hz a-c voltage to the anode of the magnetron."     

Invloed van de bemesting op de kurkvorming van de aardappelknol

(with a summary in English) Instituut voor Phytopathologie Laboratorium voor Mycologie en Aardappelonderzoek     

Resistance of wheat pathogen Zymoseptoria tritici to DMI and QoI fungicides in the Nordic-Baltic region - a status

Septoria tritici blotch (STB) caused by the ascomycete Zymoseptoria tritici (Z. tritici) is currently the most prevalent foliar disease in wheat in the Nordic-Baltic region. Fungicide availability in this region differs greatly and is generally more limited than in other European regions. Monitoring of fungicide sensitivity is an essential tool to survey changes in fungal populations in order to react and be able to adapt recommendations for fungicide use. In this study the authors give an overview of the current situation of 14α-demethylation inhibitor (DMI) and quinone outside inhibitor (QoI) sensitivity of Z. tritici from Scandinavia and the Baltic countries. A total of 985 isolates from the Nordic-Baltic region were investigated for EC₅₀ of DMI epoxiconazole and prothioconazole. Fungicide sensitivity remains at a high level with values ranging from 0.07 to 0.48 mg L^?1 for epoxiconazole and 1.17 to 9.47 mg L^?1 for prothioconazole. Point mutation I381V in the DMI target gene CYP51 was dominant throughout the region, but mutations D134G, V136A/C and S524T were also detected in the population in 2014. Screening for inserts in the CYP51 promoter region revealed that a ~ 1000 bp insert is predominant in the entire region. Only a single isolate was found in Denmark, harbouring the 120 bp insert, known to reduce fungicide sensitivity. Two Danish isolates which had elevated resistance levels were associated with an enhanced efflux. Significant differences were found across the area for the presence of G143A, conferring QoI resistance. As there is only limited access to results from this area, these findings can serve as reference for future fungicide sensitivity investigations and for evaluation of changes in the Northern European Z. tritici population.     

Population structure and frequency differences of CYP51 mutations in <Emphasis Type="Italic">Zymoseptoria tritici</Emphasis> populations in the Nordic and Baltic regions

Septoria tritici blotch caused by the fungus Zymoseptoria tritici (formerly Mycosphaerella graminicola) is one of the most yield-reducing diseases worldwide. Effective disease management involves the use of resistant cultivars and application of fungicides. In this study, the population structure and genetic diversity of 183 Z. tritici isolates from Denmark, Sweden, Finland and the Baltic countries were analysed by molecular markers. In population structure analysis, isolates from Denmark and Sweden were grouped together, whereas isolates from the Baltics and Finland were grouped together. Analysis of genetic diversity and ?-values confirmed the division of Nordic and Baltic regions. Danish isolates sampled from different regions and different varieties were not genetically different. However, significant genetic differences were detected between isolates sampled from different years in Denmark and for isolates sampled from specific cultivars in different years. Additionally, the frequency of several known point mutations in the gene cyp51, conferring decreased sensitivity to DMI fungicides, was investigated. Several of the examined mutations were detected at a lower frequency in Baltic isolates compared to Danish and Swedish isolates. Analysis of the Danish population revealed a significant increase in specific mutations over the years. Lastly, some mutations were significantly more frequent in isolates derived from certain varieties. By using different resistance sources in breeding programmes and application of a wide range of fungicides, a sustainable and efficient disease management can be obtained.     

Mantle discontinuity structure beneath the southern east pacific rise from P-to-S converted phases

Receiver functions derived from teleseismic body waves recorded by ocean-bottom seismometers on the southern East Pacific Rise reveal shear waves converted from compressional waves at the mantle discontinuities near 410- and 660-kilometer depth. The thickness of the mantle transition zone between the two discontinuities is normal relative to the global average and indicates that upwelling beneath the southern East Pacific Rise is not associated with an excess temperature in the mantle transition zone.     

Black-hair follicular dysplasia in a New Zealand Huntaway dog

CASE HISTORY: A 6-year-old intact male New Zealand Huntaway dog had slowly progressive alopecia that was first observed at 12 weeks of age.

CLINICAL FINDINGS: Patchy alopecia was confined to the black-haired areas of the body, and was most evident on the head and dorsum of the body; tan-haired areas of skin appeared normal. Histological examination of black-haired skin revealed distended melanocytes and large aggregates of melanin within, and surrounding, the hair follicles and the epidermis. Macrophages distended with melanin were also visible within the perifollicular and superficial dermis, and follicular lumina were often plugged by keratin that contained aggregates of melanin. The follicles were dysplastic and few hair shafts were visible emerging from follicular infundibula within the sections.

DIAGNOSIS: The clinical and histological findings were consistent with black-hair follicular dysplasia (BHFD).

CLINICAL RELEVANCE: This is the first report of BHFD in a dog in New Zealand, and is the first report in a Huntaway. The most significant effect of BHFD is a predisposition to follicular plugging and secondary bacterial skin infections. Due to the hereditary nature of the follicular dysplasias, breeding from affected dogs should be discouraged. Histological examination of the skin is required to differentiate between the different follicular dysplasias as well as differentiating between follicular dysplasia and follicular atrophy due to endocrinopathy.     

‘Progressive ataxia’ in a Charolais steer in New Zealand

Extract

Signs of progressive central nervous system disease in cattle aged 2 years and older should alert farmers and veterinarians to consider the possibility of bovine spongiform encephalopathy (BSE). Government veterinarians routinely assess all livestock slaughtered in meat plants in New Zealand for signs of any nervous disorder, including abnormalities of behaviour and mental state and abnormalities of posture and gait.     

Clonality and long-distance migration of Puccinia striiformis f.sp. tritici in north-west Europe

The biotrophic fungus Puccinia striiformis f.sp. tritici , a basidiomycete that causes yellow rust on wheat, is spread by wind-dispersed spores. Analysis of amplified fragment length polymorphism (AFLP) variation showed that the fungus frequently migrates between the UK, Germany, France and Denmark. There is no biological evidence for sexual or parasexual reproduction under natural conditions, and this was supported by the lack of recombination, as revealed by AFLP, over the time and area represented by the samples in this study. A phylogeographic analysis revealed that there was effectively a single, clonal population in the four countries, up to 1700 km apart, consistent with a 'continent-island' model in which Denmark is the recipient of migrants from other countries. In five cases, specific pathogen clones were dispersed between the UK and Denmark, and on at least two recent occasions clones were also spread from the UK to Germany and France, causing outbreaks of yellow rust on wheat cultivars that were previously resistant to the disease in these countries. The agronomic consequences of migration were enhanced because of the limited genetic diversity for yellow rust resistance in wheat cultivars in the area. These results demonstrate that long-distance migration of pathogen clones, coupled with low diversity in the host species, may cause previously useful resistance genes to become ineffective for disease control on a continental scale.     

A national programme for mastitis control in Australia: Countdown Downunder

In 1998, Countdown Downunder, Australia's national mastitis and cell count control programme, was created. With funding from the country's leading dairy organisation, Dairy Australia, this programme was originally intended to run for three years but is now in its tenth year. As it was the first time Australia had attempted a national approach to mastitis control on the farm, the first three years of the programme were largely concerned with the development of resources to be used by farmers and service providers. The second three years were devoted to training with both groups. Since that time, Countdown Downunder has entered into a second resource development phase. The goal of the programme was to achieve a reduction in the bulk milk somatic cell count from the Australian dairy herd. To achieve this, the programme had to develop resources with clear and consistent messages around mastitis and somatic cell count control on farms. It was determined that progress toward the goals would be made more rapidly if service providers were trained in the use of these resources prior to farmers. This paper reviews the Countdown Downunder programme from 1998 to 2007.