WSU Extension


Tomato : White mold
(revision date: 6/6/2014)

White mold is caused by a fungus. It typically attacks dead flower petals or dead leaves, then spreads into living tissues. The infection often starts in branch crotches or at the base of stems. Initial symptoms may include a rapidly spreading soft rot. Affected tissues turn gray and may be covered with a mass of cottony, white fungal growth. Hard, black fungal structures (measuring 1/4" to 1") are often produced on the cottony growth and inside the affected stems. Infected stems may be tan, then eventually turn a bleached, bone-like white. Disease development is favored by long periods of cool, wet weather.
Management Options

Non-Chemical Management
  • Plant in well-drained soils.
  • Avoid overhead irrigation.
  • Space plantings to improve air circulation, particularly around the base of the plants.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

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Caption: Interior stem showing white fungal growth and black sclerotia
Photo by: R.S. Byther