Main symptoms

Pratylenchus spp. cause numerous lesions of varying size appear on the roots. Their coloration varies from yellowish to reddish brown (Figure 1). This latter coloration is linked to the formation of phenolic compounds in the tissues.

Eventually, larger or smaller portions of the cortex break down (Figure 2).

When the attacks are severe, a large proportion of the root system may disappear (Figure 3).

Placed in this situation, the plants do not grow very vigorously; a variable proportion of leaves can chlorose (Figure 4).

Observation of the roots under a light microscope makes it possible, in a good number of cases, to observe nematodes with a clearly visible stylet (Figure 5) in or near the tissues.