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Meloidogyne spp. (Root-knot nematodes)


The species of Meloidogyne , nematodes ( root-knot nematodes ) , affect many vegetable crops grown in rotation with tomato (salad, eggplant, melon ); it is therefore not surprising to observe their effects in many crops, mainly in soil.

The root symptoms caused by these nematodes, galls (figures 1 and 2) and swellings (figures 3 and 4) are very characteristic and easily identifiable. To confirm your diagnosis, you can cut galls in half. One to several round, whitish masses, corresponding to swollen adult females , are easily visible (Figures 5 to 8). These root alterations greatly disrupt the functioning of plants, all the more so as the population level in the soil is high. Also, they can be the cause of reduced plant growth, wilting and / or sometimes yellowing, as well as dieback.

Several species of Meloidogyne have been reported on tomato: M. incognita , M. javanica , M. arenaria , M. hapla (the galls of this last species are said to be smaller and rounder than those of the other species)

In France, several species are rife on tomato. In general, nematodes, like other soil-borne pathogens, are observed in tired soils that have repeatedly borne sensitive plants, and in particular tomatoes. It is therefore not surprising to observe on the ground parasitic root complexes involving, in addition to root-knot nematodes, R. solani , C. coccodes , P. lycopersici  ...

It should be noted that root-knot nematodes have been implicated in the release of certain resistances in tomatoes, such as that to vascular fusarium, for example. In addition to rootstocks, some tomato varieties are resistant to several species of Meloidogyne . This resistance is not absolute, and some galls can still be observed on the roots of resistant plants.

Finally, it should be noted that the discontinuation of the use of methyl bromide and the use of less efficient alternative methods largely explain the resurgence of soil-borne pests, in particular root-knot nematodes.

For further information on this nematode, you can consult the Meloidogyne spp. .
Last change : 05/10/21
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Figure 1
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Figure 2
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Figure 3
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Figure 4
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Figure 5
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Figure 6
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Figure 7
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Figure 8