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Blue Mold Gallery

View the 360 Rotator showing multiple images of the external disease symptoms.

View the 360 Rotator showing multiple images of the internal disease symptoms.


Blue Mold on Apples

Blue mold (primarily Penicillium expansum) is a very common postharvest fungal disease on apples worldwide. This disease is of economic concern  to both the fresh-fruit industry and the fruit-processing industry because some strains produce the mycotoxin patulin, which can rise to unacceptable levels affecting the quality of apple juice.

For full description of Blue mold and management visit our Blue Mold Postharvest Disease page.

Click on images below to see full size.

Red Delicious apple with blue mold side infection showing blue-green spore masses.

Blue mold originating from infection of wound on fruit; decayed area brown, soft and watery, with a sharp margin; blue-green spore masses visible. Photo: CL Xiao, USDA-ARS.

Internal view of a red delicious apple with blue mold infection showing that the decayed tissue is completely separable from the healthy tissue.

Blue mold decayed tissue completely separable from the healthy tissue. Photo: CL Xiao, USDA-ARS.

Granny Smith apple with a side wound infected with Blue mold showing spore masses.

Blue mold originating from infection of wound on a Granny Smith fruit; spore masses formed at the infection site. Photo: CL Xiao, USDA-ARS.

Fuji apple infected at the calyx end with blue mold, often associated with drenching.

Calyx-end blue mold on a Fuji fruit; usually associated with drenched fruit.Photo: CL Xiao, USDA-ARS.

Blue mold on Fuji apple. Brown, soft and watery lesion with sharp margin. Originating from a wound. Notice white & green spore masses. Photo: A. Amir, WSU Plant Pathology.

Blue mold originating from wound infection on Granny Smith apple. Spore masses formed along the infection site. Photo: CL Xiao. USDA-ARS.

Cross section of blue mold lesion on Granny Smith apple. Sharp margin between decayed and healthy tissue. Photo: A. Amiri, WSU Plant Pathology.

Decayed tissue completely seperated from the healthy tissue, leaving a “bowl-like”cavity. Photo: CL Xiao, USDA-ARS.

Advanced blue mold . Conidia are very light and easily dispersed to neighboring fruit with the slightest movement. Photo: A. Amiri, WSU PLant Patholgy.

Honeycrips apple showing the brown, soft, watery lession with a definative edge. Photo: TJ Mullinex, Good Fruit Grower.

Internal view of a Honeycrisp apple with blu mold infection. The decayed tissue was esily separated from the remaining healthy tissue. Photo: TJ Mullinex, Good Fruit Grower.

View looking straight into a Honeycrisp apple with blue mold infection originating from a side puncture. The decayed tisses was easily separable from the healthy flesh. Photo: TJ Mullinex, Good Fruit Grower.


Blue Mold on Pear

Click on images below to see full size.

Blue mold on a Bosc fruit; watery decay lesion with white mycelium and blue spore masses. Photo: CL Xiao, USDA-ARS.

Stem-end blue mold on a Bosc pear fruit after an extended period of storage. Photo: CL Xiao, USDA-ARS.

White mycelium and blue spore masses at the decayed area of a d’Anjou fruit. Photo: CL Xiao, USDA-ARS.

Stem-end blue mold commonly seen on d’Anjou pears, particularly after an extended period of storage. Photo: CL Xiao, USDA-ARS.

Washington State University