Root abnormalities

One can observe various abnormalities such as cysts, tumors or galls on tobacco roots. These different root deformities can be caused either by pests such as nematodes belonging to the genera Globodera spp. ("cyst nematodes") or Meloidogyne spp. ("root-knot nematodes", figure 1), or parasitic plants such as Orobanche ("broomrape").

Figure 1	Figure 2

Remember that some non-parasitic causes, such as "false broomrape" or the presence of hardpan can also be the cause of such symptoms. 

The bacterium Agrobacterium tumefaciens, responsible for root tumors ("crown gall) of many plant species, was observed on tobacco in Italy. To our knowledge, these tumors forming on the roots are first white, then turn brown and suberous (figure 2)., they have never been observed on tobacco in France.