Plasmopara viticola the Causal Agent of Downy Mildew of Grapevine: From Its Taxonomy to Disease Management

Abstract

Plasmopara viticola (P. viticola, Berk. & M. A. Curtis; Berl. & De Toni) causing grapevine downy mildew is one of the most damaging pathogens to viticulture worldwide. Since its recognition in the middle of nineteenth century, this disease has spread from America to Europe and then to all grapevine-growing countries, leading to significant economic losses due to the lack of efficient disease control. In 1885 copper was found to suppress many pathogens, and is still the most effective way to control downy mildews. During the twentieth century, contact and penetrating single-site fungicides have been developed for use against plant pathogens including downy mildews, but wide application has led to the appearance of pathogenic strains resistant to these treatments. Additionally, due to the negative environmental impact of chemical pesticides, the European Union restricted their use, triggering a rush to develop alternative tools such as resistant cultivars breeding, creation of new active ingredients, search for natural products and biocontrol agents that can be applied alone or in combination to kill the pathogen or mitigate its effect. This review summarizes data about the history, distribution, epidemiology, taxonomy, morphology, reproduction and infection mechanisms, symptoms, host-pathogen interactions, host resistance and control of the P. viticola, with a focus on sustainable methods, especially the use of biocontrol agents.

Croatian Native Grapevine Varieties’ VOCs Responses upon Plasmopara viticola Inoculation

“…Due to the plasticity of the plants in response to the pathogen and the establishment of either a compatible or incompatible interaction, the modulation of several classes of primary and secondary metabolites alters. During the initial phases of the infection, plant reactions to oomycetes are identical, albeit less effective and slower in susceptible plants [ 4 ].…”

“…Due to the detrimental effects of chemical pesticides on the environment, and human and animal health, as well as the emergence of pathogens resistant to these treatments [ 20 , 21 , 22 ], the European Union has restricted their usage through the Farm to Fork Strategy [ 23 ]. Today, the focus lies on the development of alternative tools, such as the breeding of resistant cultivars, the development of new active substances, and the search for natural compounds and biocontrol agents that can be applied individually or in combination to eradicate the pathogen or mitigate its effects [ 4 ].…”

Spatial–Spectral Analysis of Hyperspectral Images Reveals Early Detection of Downy Mildew on Grapevine Leaves

“…Downy mildew, caused by the obligate oomycete Plasmopara viticola , is a highly destructive disease of grapevine Vitis vinifera L. [ 1 , 2 ]. The infection cycle of P. viticola begins during the spring with the germination of oospores (resting stage of the pathogen resulting from sexual reproduction) with the help of the warm and humid weather [ 1 , 2 ]. The sporangia disperse onto the vegetation by rainfall and release zoospores.…”

“…The sporangia disperse onto the vegetation by rainfall and release zoospores. The gem tube of zoospores enters the plant through the leaf stomata, grows into the plant tissue and produce new sporangia [ 1 , 2 ]. The infection is characterized by oil spots on the adaxial leaf surface and whitish downy covers on the abaxial surface, which are tufts of sporangia [ 1 , 2 , 3 , 4 ].…”

“…The gem tube of zoospores enters the plant through the leaf stomata, grows into the plant tissue and produce new sporangia [ 1 , 2 ]. The infection is characterized by oil spots on the adaxial leaf surface and whitish downy covers on the abaxial surface, which are tufts of sporangia [ 1 , 2 , 3 , 4 ]. With favourable conditions, downy mildew can quickly infect the entire crop.…”