WSU Extension

Hortsense

Common Cultural : Oedema
(revision date: 4/30/2013)


Biology
Oedema usually appears first on the lower leaf surface as watery blisters. As they age they become brown, yellow, or rust-colored and may resemble disease symptoms. It is very common on geranium but also occurs on many types of plants, particularly those having fleshy leaves. High soil moisture, high humidity, and soil temperature warmer than air temperature favor symptom development.
Management Options

Non-Chemical Management
  • Do not overwater.
  • Keep greenhouse humidity low, by heating if necessary.
  • Maintain higher greenhouse temperature.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images
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Caption: Oedema on hosta
Photo by: R.S. Byther
Caption: Oedema on geranium
Photo by: R.S. Byther
Caption: Oedema on geranium
Photo by: R.S. Byther
Caption: Oedema on camellia
Photo by: B.M. Johnson