Cole Crop Diseases
Cole Crop Diseases
Wirestem, Bottom Rot, Head Rot
All 3 names apply to the same fungus. The symptoms are darkened and girdled stems near the soil line. The plants are weak and only produce small heads or may wilt and die. Bottom rot develops when the plants are in the field. Dark, slightly sunken spots form on bottom leaves near the soil. Head rot is a progressive state of bottom rot in which the rot spreads to nearby leaves during moist weather or in storage. The causal fungus is soil borne. The disease is worse in moist conditions. No chemical controls are listed.
The early symptoms of black leg are dark sunken cankers at the stem base or light brown circular spots on the leaves. Plants wilt when the canker girdles the stem. Black specks form in the cankers and spots. The disease is easily spread and overwinters in diseased crop residues. No chemical controls are listed.
Alternaria Leaf Spot
Spots with dark concentric circles form on the lower leaves. A dusty fungal growth occurs on the spots in moist weather. When the crop is stored, the spots enlarge. Soft rot may get started in dead leaf spots. Wet conditions increase disease development. The disease overwinters in seed and diseased crop residues. Use Copper(1) or Sulfur(7) on Broccoli, Brussels Sprouts, Cabbage and Cauliflower.
Downy mildew begins as small, yellow leaf spots. Later the spots turn brown with blue/black, lace-like markings. During periods of moist weather a mold forms on the underside of the spots. The vascular tissue discolors. The disease is worse in cool wet weather in spring and fall. Downy mildew can predispose plants to bacterial soft rot. The disease overwinters on seed and on crucifer weeds. Use Copper(1) or Chlorothalonil(0) on Broccoli, Brussels Sprouts, Cabbage and Cauliflower.
Infected seedlings turn yellow and die. Yellow, wedge shaped areas form at the leaf margins and expand inward, toward the center of the leaf, on mature plants. The affected areas later turn black and die. The vascular tissue in affected areas is black. The heads are dwarfed and one sided. The lower leaves fall off and soft rot often develops. The bacteria overwinters on seed and in diseased crop residues and is easily spread. No chemical control is listed.
Infected plants are yellow, dwarfed, and infected leaves often have purple edges and brown bases. The vascular tissue darkens, starting from the plant base and moving toward the leaf margins. The fungus persists in the soil for many years. The disease is favored by high soil temperatures. No chemical controls are listed.
Above ground symptoms of clubroot are wilting and leaf yellowing. Below ground, the roots are greatly enlarged. The fungus can remain in the soil at least 7 years.
|Visual title - Visual size||Visual title - Visual size|
|Black rot on savoy cabbage - 42K||Black rot on savoy cabbage - 42K|
|Black rot on cabbage, internal symptoms - 25K||Club root on chinese cabbage - 34K|
|White rust on mustard greens - 57K|