Bacterial Blight of Geranium

Disease Information

Bacterial Blight (Bacterial Leaf Spot, Stem Rot or Wilt)

Xanthomonascampestrispv. Pelargonii

Symptoms

Leaves: Infected leaves typically develop two types of symptoms: small, discrete, water-soaked or brown spots and V- or pie-shaped angular lesions; some leaves develop distinctly darkened veins and wilt at leaf margins .

Stems: When infection is systemic, the entire plant develops typical wilt symptoms, often first appearing in the lower leaves; leaves become flaccid and branches wilt and dieback; stems can blacken and shrivel into a dry rot; infected cuttings fail to root and slowly rot from the base upward; stems become dull black-brown and are drier than Pythium root rot; plants with systemic infection collapse and die; systemically infected ivy geraniums don`t wilt but develop symptoms that can be confused with nutritional or insect problems;

Management

- Start with a clean house and equipment and a sterile, well-drained medium

- Isolate stock plants from propagation area

- Use disease-free cuttings

- Keep geraniums from different suppliers separate

- Separate seedling geraniums from cutting types

- Avoid growing perennial geraniums (Geranium spp.) near Pelargonium spp.

 - Avoid placing ivys in hanging baskets above seedling or cutting geraniums

- Use drip irrigation if possible

- Rogue and remove symptomatic plants

- Minimize traffic flow in house

CHEMICAL CONTROL

 - Among the compounds registered for use is copper sulfate pentahydrate



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