Corky Root Rot
Characteristic banding pattern of corky root rot (left) and roots with severe case of corky root rot (right). Note the cracked, corky bark-like roots.
Characteristic v-shaped necrosis and yellowing of leaves (left) and vascular discoloration of tomato plants consistent with Fusarium wilt or Verticillium wilt (middle; right).
Tomato plant with Fusarium wilt (left). Note the yellow discoloration on one half of the plant (right).
Root Knot Nematode
Tomato roots with severe root knot nematode galling (left; middle; right).
Black Dot Root Rot
Roots with sclerotia of Colletotrichum coccodes, the causal agent of black dot root rot. The honey-brown discoloration is also characteristic of this disease (left; middle; right).