البياض الزغبي في العنب : دراسة مرجعية

الملخص EN

The grapevine (Vitis spp.) has been cultivated all over the world and viticulture is one of the major horticultural industries of the world.

Downy mildew is one of the most severe diseases of all cultivars of grapes in the species Vitis vinifera and many Vitis intraspecific hybrid cultivars.

The disease is highly destructive of grapevines in all grape-growing areas of the world where there is spring and summer rainfall at temperatures above 11°C.

When the weather is favorable and no protection against the disease is provided, downy mildew can easily destroy 50 to 75% of the crop in one season.

The pathogen, Plasmopara viticola, was first collected and studied in the north-eastern USA in 1834.

It is a heterothallic oomycete, obligate parasite and its mycelium is aseptate.

Asexual reproduction occurs by the formation of sporangia which are produced through the stomata of infected organs.

Sporangia release zoospores, which can penetrate the healthy tissues via the stomata.

As the leaves senesce, sexual reproduction occurs through the fusion of antheridia and oogonia within the host tissue.

The resulting sexual spore is an oospore, which is the survival and resting stage of the pathogen.

Wrong agricultural practices have led to catastrophic dispersal of P.

viticola, which is native to northeastern America, and it is generally accepted that the pathogen spread to Europe and other different countries on American grapes imported for use as rootstocks resistant to phylloxera.

This article review traces and demonstrates the current and historical knowledge of the disease origin, symptoms, means of dispersal as well as disease cycle and epidemiology.

Also, current and historical knowledge of disease management includes cultural practices, genetic resistance and chemical control in detail have been discussed.