Main symptoms

More or less large and regular white galls characterize the presence of nematodes belonging to the genus Meloidogyne spp. on the root system of melon (Figures 1 and 2). These gradually turn brown and suberise as they evolve, and their number and shape depend on the species prevailing and the rate of inoculum in the soil.

The two most reported species on melon, M. incognita and M. javanica , cause large galls sometimes covering the entire root system (Figures 3 and 4). Longitudinal swellings more or less tortuous and extensive are also observed (figure 5).

A cross section of the galls makes it possible to highlight the mature females (figure 6), thus confirming the parasitism of these nematodes.

These root alterations disrupt the absorption of water and mineral elements, and therefore the development of plants which exhibit more or less reduced growth. The foliage can be chlorotic, and wilting (Figures 7 and 8) sometimes occurs during the hottest hours of the day. The lower leaves of severely affected plants show early senescence.

Size Fruit and yields are reduced.