Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie


Shelf life

CAS and PHP session cookies

Login credentials, session security



Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie


Shelf life


Trace the visitor's route in order to establish visit statistics.

13 months


Store the anonymous ID of the visitor who starts the first time he visits the site

13 months


Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at or by post at :


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

Last update: May 2021

Menu Logo Principal Plant pathology unit - INRA AVIGNON

Pathologie vegetale

Zone de texte éditable et éditée et rééditée

Biological control

Durability of efficacy of biological control agents against Botrytis cinerea

Estimate of potential resistance of Botrytis cinerea to biofungicides

The potential resistance of Botrytis cinerea to biofungicides was studied during a thesis defended in 2009

  • Ajouz, S. 2009. Estimation du potentiel de résistance de Botrytis cinerea à des biofongicides. Thesis supervised by Bardin, M. (MISTRAL team) and El Maataoui, M. (University of Avignon). The pdf file of the thesis can be downloaded on the website "TEL", multidisciplinary theses server. Some chapters are written in English.

Striking result of this study:

  • This study provides evidence that a fungal plant pathogen is able to gradually build-up resistance to an antibiotic (pyrrolnitrin) produced by a biocontrol agent. However, the high level of resistance to pyrrolnitrin has resulted in a high fitness cost.

The loss of efficacy of biocontrol agents may result from:

  • the selection of isolates of the pathogen existing in natural populations and with reduced susceptibility to the biological agent protection
  • the ability of the pathogen to produce mutants with reduced susceptibility to the agent of biological protection under the selection pressure exerted by the continuous use of the product.

The study has been focused on the antibiotic pyrrolnitrin produced by various bacteria described as potential biological control agents against B. cinerea. The results on this topic concern:

  • frequency and mechanisms of resistance in B. cinerea
  • future of "overcoming" strains of B. cinerea

Frequency and mechanisms of resistance in B. cinerea

  • evidence in natural populations of B. cinerea of isolates with less sensitivity to the pyrrolnitrin antibiotic produced by biological control agents
  • relationship between the slightest sensitivity to pyrrolnitrin and multidrug resistance of B. cinerea isolates
  • rapid development of mutants with high levels of resistance to the pyrrolnitrin for some isolates in experimental conditions in vitro
  • relation between the high resistance to pyrrolnitrin and resistance to botryticides
    • Ajouz, S., Nicot, P. C. Bardin, M. 2010. Adaptation to pyrrolnitrin in Botrytis cinerea and cost of resistance. Plant Pathology, 59, 556-566.
    • Ajouz, S., Walker, A. S., Fabre, F. , Leroux, P.,  Nicot, P. C. and Bardin, M. 2011. Variability of Botrytis cinerea sensitivity to pyrrolnitrin, an antibiotic produced by biological control agents. BioControl, 56, 353-363.
    • Fillinger-David, S. H., Ajouz, S., Nicot, P., Leroux, P., Bardin, M. 2012. Functional and structural comparison of pyrrolnitrin- and iprodione-induced modifications in the class III histidine-kinase Bos1 of Botrytis cinerea. Plos One, 7, e42520.

Click on the figures to enlarge



Future of "overcoming" strains

  • high fitness cost for the resistant isolates in absence of antibiotic pressure compared to sensitive isolates: evidence of a decrease of the mycelial growth  and sporulation in vitro and reduced aggressiveness on plant tissues (tomato and apple)
  • comparison of the cytohistological development of resistant and sensitive isolates to the antibiotic in planta: no spread of the mycelium throughout the petiole and changes of mycelial structures for the resistant isolate
    • Ajouz, S., Bardin, M., Nicot, P.C., and El Maataoui, M. 2011. Comparison of the development in planta of a pyrrolnitrin-resistant mutant of Botrytis cinerea and its sensitive wild-type parent isolate. European Journal of Plant Pathology, 129, 31-42.

Click on the figures to enlarge


Ajouz, S., Bardin, M., Nicot, P.C., and El Maataoui, M. 2011. Comparison of the development in planta of a pyrrolnitrin-resistant mutant of Botrytis cinerea and its sensitive wild-type parent isolate. European Journal of Plant Pathology, 129, 31-42

© Ajouz  - INRA PACA Avignon

Development of biocontrol agents against B. cinerea

  • Selection of bacteria and fungi efficent against B. cinerea
  • Development of strain-specific markers for the detection of the biocontrol agent Microdochium dimerumL13
    • Bardin, M., Bourgeay, J.-F., Pascal, M., Nicot, P. C. (2018). Effect of drench application of biocontrol preparations on tomato plants against Botrytis cinerea and Oidium neolycopersici. IOBC WPRS Bulletin, 135, 5-6.
    • Bardin, M., Comby, M., Lenaerts, R., Nicot, P. 2013. Diversity in susceptibility of Botrytis cinerea to biocontrol products inducing plant defence mechanisms. IOBC WPRS Bulletin, 88, 45-49.
    • Bardin, M., Comby, M., Troulet, C., Nicot, P. 2013. Relationship between the aggressiveness of Botrytis cinerea on tomato and the efficacy of biocontrol. IOBC WPRS Bulletin, 86, 163-168.
    • Bardin, M., Fargues, J., Nicot, P. (2008). Compatibility between biopesticides used to control grey mould, powdery mildew and whitefly on tomato. Biological Control, 46, 476-483. DOI : 10.1016/j.biocontrol.2008.05.012PANIST
    • Bouaoud, Y., Troulet, C., Foughalia, A., Berge, O., Aissat, K., Bardin, M.  (2018). A multi-criteria approach for the selection of efficient biocontrol agents against Botrytis cinerea on tomato in Algeria. BioControl, 63, 299-311. DOI : 10.1007/s10526-017-9851-7
    • Bouaoud, Y., Troulet, C., Berge, O., Aissat, K., Bardin, M. (2018). Diversity in the susceptibility of Botrytis cinerea strains to the biological control agent Pseudomonas helmanticensis. IOBC WPRS Bulletin, 133, 100-104.
    • Boukaew, S., Prasertsan, P., Troulet, C., Bardin, M.  (2017). Biological control of tomato gray mold caused by Botrytis cinerea by using Streptomyces spp. BioControl, 62, 793-803. DOI : 10.1007/s10526-017-9825-9
    • Nicot, P. C., Stewart, A., Bardin, M., Elad, Y. 2016. Biological control and biopesticide suppression of Botrytis-incited diseases. In: Sabine Fillinger, Yigal Elad (Eds), Botrytis – the fungus, the pathogen and its management in agricultural systems (p. 165-187). Switzerland: Springer International Publishing. DOI : 10.1007/978-3-319-23371-0_9
    • Sadfi-Zouaoui, N., Hannachi, I., Andurand, D., Essghaier, B., Boudabous, A., and Nicot, P. 2008. Biological control of Botrytis cinerea on stem wounds with moderately halophilic bacteria. World Journal of Microbiology & Biotechnology 24, 2871-2877.