Classic symptoms of Rhizoctonia on Solanaceae

• Organs attacked :

• Symptoms :
  • Damping off , occurring both pre- and post-emergence of seedlings, reddish-brown lesions on all parts of the germinated seed. Brownish weathering encircles more or less the part of the stem located at ground level, leading to the collapse and death of the seedlings.
  • Cankers at the collar of young plants or of more developed plants, reddish-brown in color and of consistency varying with the humidity of the soil (figures 1, 3 to 10).
  • More or less extensive reddish-brown root lesions, rather moist, becoming superficially corky.
  • More or less circular alterations of the part of the green or more or less mature fruits in contact with the ground. Firm at first, they consist of light rings alternating with darker ones, and gradually soften (figure 2).
  • Chlorosis, anthocyanization, wilting, even withering of the leaves (figure 11).

• >>> More pictures

• Signs : several fungal structures make it possible to confirm the presence of R. solani on or near the altered tissues:
  • often discrete whitish to brown filaments  running on germinated seeds, roots, along the stem and on the fruits;
  • more rarely ill-defined, brown masses, visible locally on the damaged tissues (pseudo-sclerotia).

• Confusions possibles : Oomycètes  ( Pythium  et  Phytophthora spp.), Sclerotium rolfsii , etc.

• Affected production areas :