ripe strawberry ready to be picked
Updated: March 10, 2021

1) Gray Mold (Botrytis Rot)

close up of gray mold on a strawberry

Gray mold
Photo: Jonas Janner Hamann, Universidade Federal de Santa Maria,
Bugwood.org
gray mold on a group of strawberries
Photo: Jonas Janner Hamann, Universidade Federal de Santa Maria,
Bugwood.org
  • Gray mold also known as botrytis rot is the major fungus disease affecting strawberries.
  • The pathogen is ubiquitous, it exists wherever vegetative matter is decaying, where weeds prevent rapid drying of fruit, where frost damages blossoms, where insects damage fruit, and where the fruit is allowed to contact or be splashed by soil.
  • Losses tend to be more severe in wet seasons. 
  • Early infections may first appear as a firm brown rot developing from the stem end. This brown rot quickly becomes covered with a dusty, gray coating of fungal spores and mycelium.
  • Most fruit rot, however, develops just as the berries begin to ripen. No resistant varieties are available.
  • Thorough sanitation (removal of weeds, dead plant material, and old or rotting fruit), straw mulch to reduce berry contact with soil, and fungicide treatments are necessary for control. 

2) Strawberry Leaf Spot, (Mycosphaerella fragariae)
 

small spots caused by strawberry leaf spot disease on foliage
Early stages of strawberry leaf spot
Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org
 
  • Leaf spot is caused by a fungus and appears as small, circular purple spots with white or gray centers on leaves and petioles.
  • When severe, this disease can cause leaf drop and reduced yields.