Main symptoms

Infection of melon by Rhizobium radiobacter (Agrobacterium tumefasciens) results in the appearance of small growths distributed over the entire root system (Figure 1). This is the first manifestation of this bacteriosis on many plants, including melon.

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 (Figure 2). They have an irregular shape and a variable size (figure 3), some reach several centimeters in diameter. 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 too much.