F. Rouxel, D. Breton
Carrot scab represents the most serious problem facing crops grown in the polders of the bay of Mont Saint Michel, where many plots have now become unfit for farming (BRETON and ROUXEL, 1991).

Symptoms, which can be seen on tuberized roots, are small brown spots on the surface. They are often very numerous and can sometimes run together. In this case, the epidermis ultimately takes on a dried, corky appearance, sometimes accompanied by longitudinal splitting, mostly in the lower part of the root. Under certain conditions, these micro-cracks can occur without any other visible alteration of the tissues.

The cause of the disease remains unknowns, despite extensive work devoted to the subject in France in recent years. Soil disinection significantly limits the damage, but no pathogenic agent has yet been identified. The fact that scrabbing occurs mainly in carrots grown in the polders (fine silt,pH 8) appears to indicate that the physical-chemical characteristics of the soil play a role; nonetheless, this hypothesis remains to be confirmed.

Until a precise diagnosis becomes available, recommendations to growers are confined to prescribing the necessary soil preparation measures, respecting the soil structure and growing techniues. A more detailed characterization of the soil in the Mont Saint michel bay is the object of current works, which are based on a plurisdisciplinary approach (pathology, pedology) and involve additional experimental studies in laboratory and in-situ.

Rouxel, F. and Breton, D. (1994). ETAT DES CONNAISSANCES SURL'ORIGINE DE LA TAVELURE DE LA CAROTTE. Acta Hortic. 354, 145-158
DOI: 10.17660/ActaHortic.1994.354.16

Acta Horticulturae