Limbus glazing

This harmless physiological condition is at the origin of oily and translucent spots , delimited by the veins, appearing on the lamina of lettuce (figure 1). These macules are observed in greenhouses where the humidity of the air is excessive and / or the water content of the plants is too high. In this context, the evaporation of the plants is insufficient and the leaf tissues saturated with water are more conducive to this manifestation. Similar symptoms can be observed after harvest when the storage temperature is too abruptly lowered.

In greenhouse, the symptoms of "Limb vitrescence" are reversible as soon as the climate of the shelter is changed by ventilating and heating it. Differences in sensitivity between varieties and types of salads are observed in the field.