Lutte intégrée contre les agents responsables des altérations externes des tubercules de pomme de terre

Context

To commercialise potato, tubers are to be free of external defaults, for fresh market as well as for industrial use. Such defaults are mainly due to pathogens as Streptomyces spp. (which induce common scab), Rhizoctonia solani, Colletotrichum coccodes and Helminthosporium solani. Control of most of these pathogens is possible through the use of chemicals pesticides. But for common scab, the only way is an integrated control including mainly the use of cropping practices such as irrigation, variety choice, amendments use or management of the intercropping period before potato. The control of common scabs is studied sinds 1994. In Belgian soils, the production of potato tubers free of common scab is now very difficult due to the intensification of the potato in the rotation and to the presence of other crops such as sugar beet or carrots sensitive to Streptomyces spp. and that maintain the inoculum potential in the soils. For these reasons, there is a urgent need to define innovative technical strategy to help producers to control common scabs.

Objectives

Objectives are to test in Belgian soils the potential control of common scabs through specific cropping practices before or during the potato crop.

Description of tasks

From 1994 to 1998, the situation of common scab in Belgian soils has been assessed by our department in collaboration with CORDER asbl (Clinique de Plantes de l'UCL à Louvain-la-Neuve) and the Proef Centrum voor aardappelteelt (PCA in Kruishoutem), in a project funded by promotional organisations (ONDAH and ORPAH) The management of irrigation of the potato crop was identified as an effective way of control, specifically for some Streptomyces species. Recently, trials have started at our department, in concertation with INRA of Rennes (F), on the management of the intercropping period before potato to control common scab.

Expected results

The survey conducted from 1994 to 1998 has supply a mapping of the distribution of common scabs in Belgian soils, together with the state of the hart on the environmental conditions that influence the tubers infection, and on the possible control of the disease. Trials have also indicated that a rational management of irrigation in the early stages of potato crop growth was able to control the appearance of one type of common scab( pitted scab ) due to Streptomyces scabies. Current field trials should give indication on the way the cropping period before potato crop has to be conducted (use of organic amendments, sowing of catch crops) to reduce common scab infection of tubers.

Contribution

Crop Production Department: Organisation and coordination of research, trials management, results analyse and diffusion, reports, scientific and technical publications..