gray mold on carnations

Gray mold (Botrytis cinerea) on carnations. Photo: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

Updated: June 14, 2021

When a plant or part of the plant (leaf, flower, fruit) rapidly collapses and dies this is called blight. The blight fungus Botrytis cinerea attacks plants in landscapes, especially under cool, wet, overcast or very humid conditions, which cause plant parts to remain wet for extended periods. In all species of Botrytis, the first symptom is a small tan spot or spots that may rapidly enlarge. If the stem is infected, girdling the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray mold produced on blighted plant parts under moist conditions. Botrytis can rapidly blight flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback. Other species of the Botrytis fungus are specialized to attack a more narrow range of plants. B. elliptica attacks lilies, causing leaf spotting that progresses up the plant, blighting leaves, stems, and flowers. B. paeoniae causes bud and shoot blight of herbaceous and tree peonies. B. tulipae causes the disease "tulip fire", characterized by a rapid spotting and blighting of tulip petals and foliage.

botrytis on impatiens flowers
Impatiens flowers showing symptoms of botrytis
botrytis on tulip
Tulip petals showing symptoms of botrytis

Management 

botrytis on pansy

Deadhead and dispose of old spent and diseased blossoms.

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