Oh dear! It’s Oedema.

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Oedema on the young leaves in this begonia basket.

Oedema, that physiological disorder that appears during periods of low light and high humidity.  There’s been quite a bit of it reported in Ontario greenhouses this spring, and unfortunately it’s related to the long rainy (or snowy!) spring we’ve been having.  If you’ve noticed salt-like crystals, odd tumour-like growths or water-soaked spots on either side of your plant leaves this disorder might be the culprit.

The disorder affects a wide variety of greenhouse ornamentals.  It’s usually noticed in spring crops like sweet potato vine (ipomea), geranium, begonia and/or petunia. Continue reading “Oh dear! It’s Oedema.”

Low Light and High Humidity: Identifying Oedema

Figure one: Typical symptoms of Odema/Intumescence.
Figure 1: Typical symptoms of Odema/Intumescence.

Oedema or edema, also known as intumescence.  This physiological disorder usually appears during periods of low light – from now through the fall, winter and into the spring.  If you’ve noticed salt-like crystals, odd tumour-like growths or water-soaked spots on either side of your plant leaves this disorder could be the culprit (Figure 1). The disorder affects a wide variety of tropical plants and succulents.  It can also affect greenhouse crops such as lilies, cyclamen, sweet potato vine, geranium, begonia, petunia, calibrachoa, ornamental peppers and other Solanaceae family plants. Continue reading “Low Light and High Humidity: Identifying Oedema”