Context
The three regions (Nord - Pas de Calais, Flanders, Hainaut) concerned by this project constitute a same basin of production for the field crops and share the same problems in term of development of the organic farming. This common project have to contribute to support this sector by the activation of the synergies between the concerned partners and the spreading of common activities.
The organic farming had a fast evolution since the beginning of the nineties. This evolution has not only been encouraged by the setting up of an official regulation that defines the minimal rules of production and protected the consumer of the abuses, but also by the set up of financial grants. The goals of the regional policies was to reach a proportion of 5 to 10% of the agricultural exploitations notified as organic in 2010. However, many problems regarding to the technical practices persist and constitute a limitation to the growth of the production and to the reconversion; thus, the rate of the organic farms represents only 3.8 %.
Regarding the potatoes cropping, late blight constitutes the main restriction for the production according to organic faming rules. Only copper based fungicides are allowed but they have serious toxic effects on the edaphic ecosystems. Consequently, the European regulation (regulation 2091/92) will limit the doses to 6 kg of copper metal per ha and per year from January 2006. In the future, spraying of copper could even be completely proscribed.
Objectives
The objectives of the project are :
- an increase of the exchanges between farmers : writing of a guide on the cultures, organization of visits and transborders exchanges between farmers ;
- an improvement of the durability of the production systems : achieving a diagnosis based on the pluri-annual follow-up of farms ;
- searching for answers to the main common difficulties : setting up of an experimentations program concerning the main crops. Experimentation and structuration of the production chain will be one of the bases of the organization of the visits and transborders exchanges between farmers.
Regarding to the protection against potato late blight, the objective is to propose protection programmes taking into account the necessity to reduce the copper doses. The studied strategies are based on the cultivar resistance, the modulation of the spraying according to the disease risks, the reduction of the doses of cupric fungicides and their total or partial substitution by alternative products.
Description of tasks
The specific tasks that have been assigned to the CRA-W are :
- research and characterization of protective products for complete or partial replacement of copper based fungicides ;
- research and characterization of the commercial cultivars with a sufficient late blight resistance of the foliage and tubers ;
- the validation of integrated protection strategies based on the use of alternative products in association or not with reduced doses of cupric fungicides, the cultivar resistance and the positioning of the treatments according to the warnings systems.
Expected results
Concerning alternatives to the cupric fungicides, 10 products should yet be tested.
Concerning assessment of the cultivar susceptibilities, 20 most resistant cultivars of 2006 field trials will be planted in 2007 in order to confirm their level of resistance.
Results obtained
We performed, in the laboratory, a screening of products and additives in order to reduce or remove copper application in the field, to control late blight disease. We evaluated a wide range of products : formulations with a low level of copper, antagonists suspensions, amino-acid extracts, plants extracts, potassium salts, sulphur formulation, organically stabilised peroxide and rhamnolipides. The product’s suspensions were applied by vaporization on potato plants. Two different application protocols were elaborated. To test fungicide protection action, the product was applied four days before inoculation of the pathogen. To evaluate the defence stimulating effect, the product was applied four times during the plant growing phase. The last vaporization was performed 4 days before inoculation.We also evaluated the resistance of the product to leaching risk.Thereafter, pathogen suspension was applied as droplets of 5x104 spo/ml on detached leaves. The leaves were then incubated (18°C , RH > 90%, 6 days) in order to record symptoms development.The best results were obtained with formulations integrating reduced doses of copper and with potassium salts (phosphates). Rhamnolipides and two additives (H2O2 and amino-acid suspension) presented also interesting results to be confirmed in the field. In conclusion of those lab trials, we concluded that, among the wide range of products and additives proposed on the market, very few has a real efficiency. The efficiency of the most interesting products has also been evaluated in the field. All the promising additives tested in the laboratory didn’t permit a good protection of the plants. However, one potassium phosphite gave good protection results, even better than the copper sulphate (1/4 dose). The rhamnolipides permitted also to reach similar level of field protection than copper sulphate. The protective programs based on the application of cupric fungicides with a dose of 800 gr, per ha and per pulverization, did not prevent the total destruction of foliage by late blight in the conditions of the trial (strong pressure due to artificial inoculation and presence of unprotected rows). However, they permitted to delay the foliage destruction by about 15 days, regarding to the less efficient treatments, and to get an acceptable yield.The spraying program according to the warnings system was statistically better that the systematic weekly spraying program.Cultivars’ sensitivity has also been evaluated in the field. Each year we tested about 30 cultivars among which 15 new cultivars, collected in the market, are inserted yearly. The trials have been performed several years and on different sites (Flanders, Wallonia and France). We get interesting results with the following cultivars: Sarpo Mira, Gasore, Eden, Agnes, Junior, Spirit and Remarka. Finally, we also tested the technological features of those cultivars in order to identify their economical potentialities.
Partners
SRPV at Nord-Pas de Calais (F)
FREDON at Loos-En-Gohelle (F)
CARAH at Ath (B)
PCBT at Beitem (B)
CRAW off coordinator
Sébastien Labrune
Groupement des Agriculteurs Biologiques du Nord (GABNOR) - Pas de Calais
Z.I. Le Paradis
F-59133 Phalempin
France
E-Mail : gabnor@wanadoo.fr
Funding
- CE - Regional politics - FEDER
- DGARNE