Mildiou de la pomme de terre : une approche systémique

Une présentation réalisée à l’occasion d’un séminaire organisé le 25 novembre 2014 à Courtrai par le CRAw et la FIWAP avec le soutien de l’APAQw.

Systemic analysis of the mildew issue in the Belgian potato system

Mémoire de  Simon Yzerbyt

Potato late blight caused by the oomycete Phtyophthora infestans (Mont.) de Bary may be the best known, longest studied and still amongst the most destructive of all plant diseases. Today, late blight is mostly controlled by the preventive use of fungicides, which has serious ecological consequences. As resistance against these fungicides increases in P. infestans populations, the number of necessary applications to fight the plague grows over time, reinforcing these ecological effects. At the same time, public opinion and societal pressure creates an additional pressure on the production system and the European agricultural policies tend to reduce the use of fungicides and pesticides.

Our objective is to explore a series of alternatives that meet the requirement of rendering the management of potato late blight more sustainable in a near future. The study relies on a systemic and qualitative approach, based on twenty-two semi-directed interviews with various types of actors of the system. The emphasis is on the point of view of the actors with respect to current and future management of potato late blight in the Belgian potato system. The collected data provide a clear view of the different ways of struggle that the actors know and/or use against late blight and offer a critical comparison of their different visions regarding the solutions to the issue and the barriers that prevent their implementation.

The study reveals the complexity of the issue and confirms the existence of a lock-in. It suggests that three main strategies for the introduction of a positive change are available, namely the adoption and/or creation of resistant varieties, a more reasoned and better regulated use of fungicides, and the capitalization on IPM methods. The majority of the actors identified the consumers and their preferences as the main obstacle for change. The fact that this so-called ‘external’ reason is given for the lock-in has direct consequences on the willingness of the actors ‘inside’ the system to modify the current situation. This means that consumers have to be included in the system, so as to weigh on the decision process and change the current posture of the actors inside the system. Turning to fungicides, the lock-in is maintained due to the efficiency and dependency of the current system on their use. A change at this level will be likely to take place if authorities more decisively enter the picture and change the regulations or if sensitized consumers succeed in changing the actors’ habit concerning the broad adoption of the fungicide-dependent Bintje and ‘Bintje-alike’ varieties. Regarding the scaling-up of IPM methods, the organic sector can play a major role in the knowledge transfer process towards the conventional sector. This would however come along with a source of inoculum.

For each of these various solutions, the feasibility and temporality differ and has to be taken into account so as to ensure a transition towards a more sustainable management of potato late blight. In conclusion, this study shows that alternatives exist concerning the use of fungicides in order to manage potato late blight but, that in order to exit the existing lock-in currently characterizing the Belgian potato system, various actions need to be undertaken in order to modify the way the actors currently see their relations with the other actors and the options available to them.


Version pdf (anglais) : Mémoire Simon Yzerbyt fini

1 Commentaire

  1. : Les gens ayant réussi à remplir 160 Go uniquement avec de la musique doivent être très rares… l&isluo;utrqité d’un ipod d’une telle capacité doit forcément être de mettre d’autres choses dessus…

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