Infection by Rhizobium radiobacter (Agrobacterium tumefasciens) gives rise to the appearance of small growths on certain roots (figure 1), particularly close to the surface of the soil or the substrate (figure 2) are the first manifestations of this bacteriosis on many plants, including tomato. At the start of development, these young tumors are smooth, whitish and rather spherical. As they age, they suberise on the surface and gradually take on a more or less marked brown tint. They have an irregular shape and a variable size, some reaching several centimeters in diameter (figure 3). They can become spongy and break down later.

The presence of these tumors on the roots does not appear to affect plant growth and fruit production.