Know more

Our use of cookies

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:

Cookie type

Means of blocking

Analytical and performance cookies

Google Analytics

Targeted advertising cookies


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

Mandatory cookies

Functional cookies

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

Menu Logo Principal

Encyclop'Aphid : l'encyclopédie des pucerons


Damage caused

Different kinds and extents of damage can be attributed to aphids. The harm can be caused at any stage in the growth of the plants, whatever the size of the surface area of the crop

The aphids feed by phloem feeding, taking the sap elaborated by the plants, diverting for their own profit part of the nutrient elements essential for plant growth This strategy induces damage, whose severity depends on the host’s stage of development and its level of sensitivity.

Traditionally, two categories of damage are recognized:

Whether the economic losses due to aphids are caused by direct or indirect damage, it is difficult or even impossible to give an accurate assessment. They fluctuate enormously depending on weather conditions, the aphids’ population density and the variety of the crop plants grown. Some surveys give average percentages of yield loss due to the direct effect of aphids at about 10-20% in peas, 10% for wheat or 5% for potatoes. Yield reduction is very much greater when viruses produce the damage: losses of up to 85% for barley infected by yellow dwarf viruses for example.

The control strategy should be guided by the type of damage. Overall the direct damage is proportional to the population size of aphids hosted by the plant, whereas viral damage depends mainly on the number of plants infected and much less on the number of aphids per plant. Hence the core principles governing the control method will be different in each case.