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Cookies are a set of data stored on a user’s device when the user browses a web site. The data is in a file containing an ID number, the name of the server which deposited it and, in some cases, an expiry date. We use cookies to record information about your visit, language of preference, and other parameters on the site in order to optimise your next visit and make the site even more useful to you.

To improve your experience, we use cookies to store certain browsing information and provide secure navigation, and to collect statistics with a view to improve the site’s features. For a complete list of the cookies we use, download “Ghostery”, a free plug-in for browsers which can detect, and, in some cases, block cookies.

Ghostery is available here for free:

You can also visit the CNIL web site for instructions on how to configure your browser to manage cookie storage on your device.

In the case of third-party advertising cookies, you can also visit the following site:, offered by digital advertising professionals within the European Digital Advertising Alliance (EDAA). From the site, you can deny or accept the cookies used by advertising professionals who are members.

It is also possible to block certain third-party cookies directly via publishers:

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Means of blocking

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The following types of cookies may be used on our websites:

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Social media and advertising cookies

These cookies are needed to ensure the proper functioning of the site and cannot be disabled. They help ensure a secure connection and the basic availability of our website.

These cookies allow us to analyse site use in order to measure and optimise performance. They allow us to store your sign-in information and display the different components of our website in a more coherent way.

These cookies are used by advertising agencies such as Google and by social media sites such as LinkedIn and Facebook. Among other things, they allow pages to be shared on social media, the posting of comments, and the publication (on our site or elsewhere) of ads that reflect your centres of interest.

Our EZPublish content management system (CMS) uses CAS and PHP session cookies and the New Relic cookie for monitoring purposes (IP, response times).

These cookies are deleted at the end of the browsing session (when you log off or close your browser window)

Our EZPublish content management system (CMS) uses the XiTi cookie to measure traffic. Our service provider is AT Internet. This company stores data (IPs, date and time of access, length of the visit and pages viewed) for six months.

Our EZPublish content management system (CMS) does not use this type of cookie.

For more information about the cookies we use, contact INRA’s Data Protection Officer by email at or by post at:

24, chemin de Borde Rouge –Auzeville – CS52627
31326 Castanet Tolosan CEDEX - France

Dernière mise à jour : Mai 2018

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Potato tuber blemishes: understanding & diagnosis




Colletotrichum coccodes 

Black dot

Helminthosporium solani

Silver scurf

Phytophthora infestans

Phytophthora erythroseptica,

Late blight

Pink rot

Pythium spp.

Leak rot

Polyscytalum pustulans

Skin spot


Violet root rot

Rhizoctonia solani

Black scurf

Rhizoctonia corky lesions

Dry core

Cracks & Deformations

Synchytrium endobioticum


Spongospora subterranea


Powdery scab


Streptomyces spp.

Common scab

Netted  scab

Russet scab

PVYNTN (Necrotic Potato Virus Y )

PMTV (Potato Mop Top Virus)

TRV (Tobacco Rattle Virus)

PSTVd (Potato Spindle Tuber Viroid)


Spraing, cracks & deformation


cracks & deformation

Globodera spp.

PCN pitting

Meloidogyne spp.

RKN galls

Slugs (Arion spp., Deroceras spp.)

Slug holes

Agriotes spp.

Wireworms holes


Tuber moth

Epitrix spp.

Potato Flea beettle

Due to climatic factors 

Cracks and deformations

Enlarged lenticells

Due to phytotoxicity

Cracks and deformation

CIPC toxicity