Botrytis on Pansies

Identification of Gray mold or botrytis blight on pansy (Botrytis cinerea).
      

APPEARANCE:

Gray to tan spots appear on pansy flower petals following infection. Periods of wet weather and stressful conditions (extreme cold or heat) favor disease development. Leaves and stems of young shoots wilt and die, turning brown to black color. Gray-brown, fuzzy patches (masses of spore) appear, a sign that the gray mold is spreading.

HOSTS:

Pansy, peony, petunia and geranium are susceptible.

SEASON:

Winter, during wet periods and unfavorable growing conditions.

DAMAGE:

Gray mold is an airborne fungus that attacks flowers and damaged or dying tissue. Pansy flower petals discolor and rot. Stems and leaves yellow, then darken, turning slimy. If allowed to spread, the disease will damage the plant.
IPM:

Conditions that favor gray mold/botrytis blight are:
high rates of fertilization
death of lower leaves
low light intensity
frequent watering
crowded plants.

If fertilization is done at the time of planting and supplemented once a month, the plant stress will be less. Remove dead lower leaves so the disease has no food source. Be sure the planting bed is in a sunny area. Allow plants to dry out between waterings. As plants mature and fill the flowerbed, remove plants that are too close together. All of these conditions will stimulate healthy pansy growth without disease.

COMMENT: If you think you have gray mold/botrytis blight in your pansies, bring a sample to the Extension office for diagnosis.