Final diagnosis


Mirafiori lettuce big-vein virus (MLBVV)

The <i> <b> Mirafiori lettuce big-vein virus </b> </i> (MLBVV, lettuce large vein virus), which causes deformation of the leaves of the heart, significantly changes the appearance and the wearing of affected lettuce.
Affected plants have a rather tormented habit which contrasts with that of neighboring healthy plants. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce fat vein virus)
A closer look at lettuce affected by <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce large vein virus) reveals that the veins of some of its leaves appear thicker.
The wider appearance and thickening of the veins induced by <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce fat vein virus) are partly responsible for the strongly blistered appearance of the lettuce leaf located on the left.
On the diseased leaf (left), we can clearly see a thickening of certain veins and deformation of the blade, compared to the control leaf on the right. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce big vein virus)
A closer observation shows that the ribs and adjoining tissues gradually thin out. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce big vein virus)
The effects of <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce fat vein virus) on "oak leaf" lettuce are quite amazing. On virus-infected plants, many leaves are narrower and their blade curls at the edge. They give the plants a particular habit which contrasts with that of neighboring healthy plants.
The growth of salads is not affected in all cases. Leaf deformations may be enough to change the appearance of plants. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce big vein virus)
Several leaves of this salad show veins appearing wider than usual. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce fat vein virus)
Yellowing of the veins and adjoining tissue of a batavia lettuce leaf. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce fat vein virus)
Eventually, large bands of tissue bordering the veins are affected, giving the blade its "large veins" appearance. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce fat vein virus)
These lettuces have deformed leaves, characteristic of the disease commonly called big vein and the cause of which is attributed to <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, the lettuce).
The symptoms of big vein are identical on red oak leaf lettuce. <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce big vein virus)
The particles of <b> <i> Mirafiori lettuce big-vein virus </i> </b> (MLBVV, lettuce large vein virus) are difficult to observe under electron microscopy.