Main symptoms

Thielaviopsis basicola is a soil fungus which causes damage mainly to the roots of melon. It gradually colonizes them, initially causing discreet small alterations of light brown color. Subsequently, they expand and take on a darker shade (Figures 1 to 3).

Arthroconidia (chlamydospores) (figures 4 and 5), typical of Thielaviopsis basicola , are visible on and in the root tissues; they allow it to be identified with certainty.

Affected plants are often poorly developed and chlorotic. They sometimes wilt on hot days.