Biology, epidemiology

Pseudomonas marginalis pv. marginalis is a bacterium which behaves quite similar to that of Pseudomonas cichorii and Xanthomonas campestris pv. vitians .


- Conservation

It persists from year to year on salad plant debris in the soil and also on several other cultivated alternative hosts such as onion, cucumber, cabbage.


- Penetration

Contamination takes place during wet periods, following splashing following rains or sprinkling irrigations. Once on the leaf surface, Pseudomonas marginalis pv. marginalis penetrates the leaf blade through wounds and through natural means: the stomata, but especially the hydatodes frequently located at the edge of the leaves.


- Dissemination

Once the tissues are invaded, many bacteria exude from the spoilage and are dispersed to other healthy leaves or plants by splashing that occurs during rain or sprinkler irrigation.


- Conditions favorable to its development

The onset of symptoms is always preceded and accompanied by wet periods. Morning dews, rainy periods, copious sprinkler irrigation are particularly conducive to Pseudomonas marginalis pv. marginalis , especially the presence of free water on the leaf blade.