Titre du document / Document title

First report of Peronospora lamii, downy mildew on basil (Ocimum basilicum) in Belgium

Auteur(s) / Author(s)

COOSEMANS J. ;

Résumé / Abstract

The leaves of basil (Ocimum basilicum), commercially available in small pots, are commonly used as a kitchen herb to flavor many dishes. These plants are produced in greenhouses as biological products, without pesticide treatments. In 2004, a leaf disease occurred in a production greenhouse, originally in some parts of the greenhouse, and the expression of the symptoms was different related to different varieties of basil. Initially the leaves were slightly chlorotic, later the leaves became necrotic resulting in a complete loss of the crop. The first diagnoses concentrated on the nutrient medium of the plants, and on a contamination in the air (e.g. ethylene, CO/CO₂) and the fungus observed on the leaves was considered as a secondary infection on dead leaves. However, microscopic observation of the grayish mass at the lower surface of the leaves showed branching conidiophores ending in sterigmata bearing single elliptical conidia (15-25 x 20-35 μm). The fungus was identified as Peronospora lamii. Inoculation tests proved that the fungus was the primary and not the secondary reason for the leaf pathogetiicity. A similar fungal disease was reported in Italy in 2003. The fungus infects Lamium and Salvia and possibly a few other plants of the mint family. Special attention should be given to the fungus because there is a potential risk that it becomes distributed all over the country on contaminated kitchen herb and because no pesticide control measures can be taken for these biologically produced herbs. It would be interesting to focus future research on the development of biological and cultural control systems.

Revue / Journal Title

Parasitica   ISSN 0031-1812   CODEN PARGAW 

Source / Source

2004, vol. 60, n^o1-2, pp. 27-27 [1 page(s) (article)]

Langue / Language

Anglais
Revue : Français

Editeur / Publisher

Association pour les études et recherches de zoologie appliquée et de phytopathologie, Gembloux, BELGIQUE  (1945-2006) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 7689, 35400013541405.0070