Oospores of Phytphthora infestans in soil provide an important new source of primary inoculum in Finland

Lehtinen, Ari; Hannukkala, Asko

doi:10.2137/1239099043633332

Cited by 42 publications

(44 citation statements)

References 18 publications

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“…Oospores have the ability to survive for at least 18 months (Andersson, 2007) outside the host plant and will result in late blight becoming a soil-borne disease. Early symptoms of late blight, presumably originating from oospores, have been reported in the Nordic countries (Andersson et al 1998;Lehtinen and Hannukkala 2004;Widmark et al 2007).…”

Section: Nordic Countriesmentioning

confidence: 99%

Epidemiology and Integrated Control of Potato Late Blight in Europe

et al. 2011

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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.

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Section: Nordic Countriesmentioning

confidence: 99%

Epidemiology and Integrated Control of Potato Late Blight in Europe

et al. 2011

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“…There are however, some characteristics of epidemics that indicate that oospores serve as primary inoculum of P. infestans. Such indications are that the spatial distribution of infection foci in a field corresponds with infections in the previous potato crop ( Andersson et al, 1998;Turkensteen et al, 2000), both mating types are present within a field early in the epidemic (Drenth, 1995) or first lesions appear low in the crop, particularly on leaves touching the soil (Lehtinen and Hannukkala, 2004).…”

Section: Oospores As Soil Borne Inoculum Of P Infestansmentioning

confidence: 99%

“…After incubation, oospore formation was observed in the leaf samples. In some of the stem samples oospores were present without incubation showing that formation could take place also under field conditions (Lehtinen and Hannukkala, 2004). A Dutch field survey of oospore formation was done in 2001 in a similar way.…”

Section: Oospore Formation Under Field Conditionsmentioning

confidence: 99%

“…Samples taken after 18 month yielded no isolates (unpublished data). Lehtinen and Hannukkala (2004) used the baiting method to determine oospore occurrence in Finnish soil samples. Of samples taken in 16 infection foci only 3 gave infection on the baiting leaves, but the results indicated that oospores could survive in the soil at least to the next growing season.…”

Section: Oospore Survival Under Field Conditionsmentioning

confidence: 99%

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The Role of Oospores in the Epidemiology of Potato Late Blight

Andersson¹,

Widmark²,

Yuen³

et al. 2009

Acta Hortic.

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Potato late blight (Phytophthora infestans) is a plant disease feared globally by farmers and the potato industry. P. infestans is a heterothallic oomycete with two mating types. Until recently the pathogen was limited to surviving between seasons as living mycelia in its host plant in most parts of the world. This was due to the fact that populations of P. infestans consisted of only one mating type (A1) in all parts of the world except Mexico, the putative centre of origin of the pathogen. Migration of new genotypes from Mexico, including genotypes of the second mating type (A2) has resulted in that now both mating types can be found worldwide. The formation of oospores is only possible if both mating types coexist. Oospores will give the pathogen the ability of surviving for extended periods of time outside its host, for example in the soil. There are reports of oospore formation under field conditions from many parts of the world. Also, in some places oospores are considered as a new, additional inoculum source and as a consequence the onset of late blight epidemics have become earlier. Oospores are formed through sexual recombination. If they act as a source of inoculum, this will increase the genotypic variation in populations of P. infestans leading to an enhanced adaptability of the pathogen. As a consequence, an earlier start of epidemics caused by oospores in the soil and a more aggressive behaviour of the pathogen due to new sexually formed genotypes could make potato late blight even more difficult to control in the future.

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“…Moreover, indiscriminate use of systemic fungicides especially metalaxyl (ridomil) provides chance to develop resistant strain of the fungus has been reported from home and abroad (Singh, 2000). A new sexually reproducing potato late blight (P. infestans) population characterised by early oospore-derived epidemics is one of the most severe threats to organic potato production (Lehtinen and Hannukkala, 2004). Innovative and effective control measures are needed if fungicide use is to be reduced or eliminated as in case of organic potato production.…”

Section: Introductionmentioning

confidence: 99%

Eco-friendly management of late blight of potato– A review

Shailbala

Kumar

2017

JANS

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Late blight of potato caused by fungus Phytophthora infestans responsible for Irish famine in the year 1845, is one of the most dramatic episode caused by plant pathogen in human history. One million people died due to famine in Ireland. So eco-friendly management of potato late blight disease is a necessary goal to be accomplished. During last many years, management strategies solely relied upon the application of fungicides due to rapid development of late blight epidemics. However, indiscriminate use of fungicide posesses a serious threat to the environment and human health. It is also responsible for built up of resistance in the pathogen and have adverse effect on beneficial organisms such as nitrogen fixers, resident antagonism and mycorrhizal fungi. So to minimize the fungicide use, eco-friendly means for late blight management are required on a priority basis. In recent years, significant changes in isolates of late blight fungus have been recorded including changes in aggressiveness to the crop also. Since, late blight is a community disease so, effective eco-friendly management must be adopted by the all producers, farmers, gardeners and growers with the help of government agencies, extension specialist and crop consultants etc. The strategy to control late blight is the prevention of establishment of Phytophthora infestans in potato crop. In this context, disease management by cultural practices is the first line of defense while forecasting system, physiological strategies, biological control, host plant resistance and bio-technological approach are essential for efficient, effective and eco-friendly management of late blight of potato.

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Oospores of Phytphthora infestans in soil provide an important new source of primary inoculum in Finland

Cited by 42 publications

References 18 publications

Epidemiology and Integrated Control of Potato Late Blight in Europe

Epidemiology and Integrated Control of Potato Late Blight in Europe

The Role of Oospores in the Epidemiology of Potato Late Blight

Eco-friendly management of late blight of potato– A review

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