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 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.