Studies on metalaxyl‐resistant <i>Phytophthora infestans</i> in potato crops in south‐west Scotland

Holmes, S. J. I.; Channon, A. G.

doi:10.1111/j.1365-3059.1984.tb01329.x

Cited by 26 publications

(13 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other authors found that an in vitro method using agar media gave repeatable and reliable result with fast growing isolates and it was compatible with the leaf disc assay as well as with field experiments (Goodwin et al, 1996;Matuszak et al, 1994). Other authors have used a potato tuber disc method or detached leaf assay (Holmes and Channon, 1984;Kadish and Cohen, 1988b). For us,…”

Section: Discussionmentioning

confidence: 90%

Genetics of Metalaxyl Resistance inPhytophthora infestans

Lee

Mizubuti

Fry

1999

Fungal Genetics and Biology

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 90%

Genetics of Metalaxyl Resistance inPhytophthora infestans

Lee

Mizubuti

Fry

1999

Fungal Genetics and Biology

View full text Add to dashboard Cite

“…Phenylamides have been applied to potato crops in Scotland for more than 20 years and 44–60% of isolates collected in the mid‐ to late 1980s were resistant (Holmes & Channon, 1984; Bain & Holmes, 1990). The virtual absence of resistant A2 isolates was thus unexpected.…”

Section: Discussionmentioning

confidence: 99%

“…The A2 mating type was first reported in 1983 (Malcolmson, 1985) but, between 1985 and 1988, only six out of 145 isolates tested were A2 (SF Carnegie, SASA, Edinburgh, personal communication). Metalaxyl‐resistant isolates were recovered from 44% of crops in south‐west Scotland in 1981 (Holmes & Channon, 1984) and from almost 60% of tuber samples tested in a survey during 1988–89 (Bain & Holmes, 1990).…”

Section: Introductionmentioning

confidence: 99%

Phenotypic and genotypic diversity of Phytophthora infestans populations in Scotland (1995–97)

et al. 2003

View full text Add to dashboard Cite

In a survey of Scottish potato late blight ( Phytophthora infestans ) populations from 1995 to 1997, nearly 500 isolates were collected from over 80 disease outbreaks in commercial potato crops and gardens/allotments. The isolates were characterized by mating type, resistance to the fungicide metalaxyl and almost 300 were examined by DNA-based AFLP fingerprinting. These data were examined alongside cropping details to determine the population structure in the context of existing disease management strategies. A1 and A2 mating type isolates were present in both commercial potato crops and gardens or allotments although they coexisted more frequently in the latter sites. One-fifth of the isolates collected were of the A2 mating type and the frequency was similar over the 3 years and amongst sites. In 1995 the proportions of isolates that were sensitive and resistant to metalaxyl were equal ( ∼ 40%) but, over the following 2 years, the frequency of resistant isolates decreased and that of intermediate isolates increased. The mating type response to metalaxyl differed markedly, with 52% of A1 and only 5% of A2 isolates being resistant. Considerable molecular diversity was observed, with over half of the isolates having unique AFLP patterns. Analysis of the molecular and phenotypic data revealed a broad clustering of the population into three groups. Many factors point to an A2 population restricted by its sensitivity to phenylamides. The majority of the A2 isolates were found in a single AFLP group, but the presence of mixed mating type samples, an increasing frequency of isolates of intermediate metalaxyl resistance and the extent of the AFLP diversity suggest occasional sexual recombination, and thus gene flow, between groups.

show abstract

“…In the UK, the first detection of strains of P. infestans resistant to phenylamides occurred in 1981, 3 years after these fungicides were registered (Cooke 1981;Holmes and Channon 1984). In the UK, phenylamides were only approved for late blight control in mixtures with mancozeb.…”

Section: Ukmentioning

confidence: 99%

Epidemiology and Integrated Control of Potato Late Blight in Europe

et al. 2011

View full text Add to dashboard Cite

Phytophthora infestans, the causal agent of late blight, is a major threat to potato production in northwestern Europe. Before 1980, the worldwide population of P. infestans outside Mexico appeared to be asexual and to consist of a single clonal lineage of A1 mating type characterized by a single genotype. It is widely believed that new strains migrated into Europe in 1976 and that this led to subsequent population changes including the introduction of the A2 mating type. The population characteristics of recently collected isolates in NW Europe show a diverse population including both mating types, sexual reproduction and oospores, although differences are observed between regions. Although it is difficult to find direct evidence that new strains are more aggressive, there are several indications from experiments and field epidemics that the aggressiveness of P. infestans has increased in the past 20 years. The relative importance of the different primary inoculum sources and specific measures for reducing their role, such as covering dumps with plastic and preventing seed tubers from becoming infected, is described for the different regions. In NW Europe, varieties with greater resistance tend not to be grown on a large scale. From the grower's perspective, the savings in fungicide input that can be achieved with these varieties are not compensated by the higher (perceived) risk of blight. Fungicides play a crucial role in the integrated control of late blight. The spray strategies in NW Europe and a table of the specific attributes of the most important fungicides in Europe are presented. The development and use of decision support systems (DSSs) in NW Europe are described. In The Netherlands, it is estimated that almost 40% of potato growers use recommendations based on commercially available DSS. In the Nordic countries, a new DSS concept with a fixed 7-day spray interval and a variable dose rate is being tested. In the UK, commercially available DSSs are used for c. 8% of the area. The validity of Smith Periods for the new population of P. infestans in the UK is currently being evaluated.

show abstract

Studies on metalaxyl‐resistant Phytophthora infestans in potato crops in south‐west Scotland

Cited by 26 publications

References 4 publications

Genetics of Metalaxyl Resistance inPhytophthora infestans

Genetics of Metalaxyl Resistance inPhytophthora infestans

Phenotypic and genotypic diversity of Phytophthora infestans populations in Scotland (1995–97)

Epidemiology and Integrated Control of Potato Late Blight in Europe

Contact Info

Product

Resources

About