Cotton Root Rot (Phymatotrichum omnivorum)
in the Low Desert

HOST: Only monocots (palms, grasses, bamboos, etc.) are immune, native plants seem to be more resistant.

SYMPTOMS:

• Infected plants suddenly wilt and die in the heat of the summer and the dead leaves remain attached to the plant.

• Infected roots have a distinctive fungal growth pattern which can be seen under a microscope as a cruciform pattern.

• Cortex pulls off easily (sloughing)

• Pancake batter-like spore mats (often confused with other harmless fungi) may appear on soil surface of infested areas, but do not spread the fungus.

CAUSE:

The fungus lives in the soil and infects roots via wounds or natural openings.

MANAGEMENT:

Plant desert natives which are tolerant of the fungus or monocots (bamboos, grasses, palms) which are immune . There is no effective treatment. By the time symptoms are noticed the roots have already been destroyed.

 

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