Wet root rot diseases of Pittosporum tobira

Disease Information

Wet root rot diseases

(Phytophthora and Pythium spp.)

 Symptoms and damage

 Above-ground symptoms are poor growth, thinning of the foliage, and yellowing of leaves, with the oldest foliage affected first. These symptoms may be one-sided on the plant. Wet rots cause a soft decay of the outer layers of roots, which can be easily stripped off between two fingers, leaving the firm, white stele intact.

COMMENTS on disease

The disease is triggered by periods of excessive soil moisture. Conditions that favor disease development include planting too deep, poor drainage, shallow rooting, and poor water management.


 Check roots of nursery-grown plants before planting into the landscape. Provide adequate drainage, and reduce irrigation. Apply labeled fungicides if problem is diagnosed early and cultural problems corrected.

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