{"id":7747,"date":"2018-11-02T14:22:00","date_gmt":"2018-11-02T12:22:00","guid":{"rendered":"https:\/\/www.torosidis.gr\/?p=7747"},"modified":"2026-09-27T20:41:06","modified_gmt":"2026-09-27T17:41:06","slug":"%cf%80%ce%b5%cf%81%ce%bf%ce%bd%cf%8c%cf%83%cf%80%ce%bf%cf%81%ce%bf%cf%82-%cf%83%cf%84%ce%bf-%ce%b1%ce%bc%cf%80%ce%ad%ce%bb%ce%b9-plasmopara-viticola","status":"publish","type":"post","link":"https:\/\/www.torosidis.gr\/en\/%cf%80%ce%b5%cf%81%ce%bf%ce%bd%cf%8c%cf%83%cf%80%ce%bf%cf%81%ce%bf%cf%82-%cf%83%cf%84%ce%bf-%ce%b1%ce%bc%cf%80%ce%ad%ce%bb%ce%b9-plasmopara-viticola\/","title":{"rendered":"Downy Mildew of grapes \u2013 Plasmopara viticola"},"content":{"rendered":"

Downy mildew is the most serious disease in , vine, especially in areas with warm and humid climates. The first symptoms of the disease in varieties of the European vine (Vitis vinifera) were recognized in the Bordeaux region around 1878. <\/p>\n\n\n\n

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Today the disease is endemic in all wine-producing regions of the world with a warm and humid climate during the period of vegetative growth of the vine. The absence of rain in spring and summer in some areas limits the spread of the disease (eg. Australia , California , Chile).<\/p>\n\n\n\n

The disease affects all green parts of the plant, especially , leaves, inflorescences and young grapes.<\/p>\n\n\n\n

The pathogen belongs to the Oomycetes , and according to the recent classification is a member of the family Peronsporomycetes (Dick 2002). This family is different from that of fungi (Mycota) and is part of the Chromista , a kingdom which includes heterogeneous microorganisms.<\/p>\n\n\n\n

In cases where the infestation with the disease is severe , the leaves fall prematurely , the production and sugar content of the grape is reduced , while the grapes are at risk of sunburn. <\/p>\n\n\n\n

Severe , infestations especially during the flowering period that are not treated , can lead to a total loss of production.<\/p>\n\n\n\n

In addition, early defoliation due to severe infestations of , downy mildew puts the next year's , production at risk as plants fail to form sufficient reserves.<\/p>\n\n\n\n

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Grape Downy Mildew | Plasmopara viticola<\/p>\n<\/div><\/div>\n\n\n\n

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All varieties of Vitis vinifera are susceptible to downy mildew infestation. Vitis vinifera , hybrids Vitis aestivalis and Vitis labrusca are less sensitive , while Vitis rupestris , Vitis cordifolia and Vitis rodundifolia are generally resistant<\/strong><\/p>\n\n\n\n

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Downy mildew is a mandatory parasite. It needs living tissues to grow. So it can grow on all green parts of the plant.<\/p>\n\n\n\n

Oospores (brooding organs) form late summer and autumn on the affected , leaves on the vine or rails. With autumn defoliation they drift into , soil where they overwinter on infected leaves. There they can remain from 3 to 5 years (many times up to 10 years).<\/p>\n\n\n\n

Oospores are the intrinsic reproductive organs of downy mildew. Their durable walls make them less susceptible to fungicides and extreme weather conditions than zoospores and spores.<\/p>\n\n\n\n

At least 10 mm of rain (and\/or irrigation ) , 10 \u00b0C or more , for at least 24 hours favor the primary infections of the disease.<\/strong><\/p>\n\n\n\n

These conditions do not always ensure the progression of , disease, but they should mobilize the wine producers.<\/p>\n\n\n\n

In particular, in order for oospores to germinate, they require:<\/p>\n\n\n\n