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ID Gallery: Phacidiopycnis Rot – Speck Rot

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five fruits in various stage of decay - image rotates to show each fruit

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showing multiple images of the external disease symptoms.

Phacidiopycnis rots are emerging postharvest diseases of apple and pear in the U.S. Pacific Northwest. These diseases have previously been reported in Europe and India and most recently in Chile. In Washington State and Oregon, Phacidiopycnis rot is common on pears, whereas speck rot is more common on apples in Washington State. Recent surveys have confirmed that these rots continue to be an emerging threat in the PNW and will require future management attention.

For more information about Phacidiopycnis rot and Speck rot and their management visit our page Postharvest Diseases: Phacidipycnis Rot.

Speck Rot in Apple

This rot of apples is primarily caused by P. washingtonensis and is referred to as Speck rot. Speck rot presents with two symptoms. Flesh infections are spongy to firm, not separable from healthy tissue, and is sometimes visually similar to gray mold. The color of the decayed area is light to dark brown, and black in advanced stages. A second symptom of infection starts at lenticels. Symptoms are brown to black specks with a white to light tan center around the lenticels. Both symptoms appear more often on the calyx and stem end of the fruit.

yellow apple covered in brown patches

Speck rot symptoms on a Golden Delicious apple. Photo: TJ Mullinex, The good Fruit Grower.

bright red apple with small brown spots on the skin

Stem-end Speck rot symptoms on a Red Delicious apple after storage. Photo: CL Xiao, USDA-ARS.

red apple, more than half covered with small brown spots

Calyx-end Speckrot symptoms on a Red Delicious apple after storage. Photo: CL Xiao, USDA-ARS.

green apple with a large brown area with white spots

Early speck rot infection developing on Granny Smith under high humidity. Photo: A. Amiri, WSU TFREC.

half apple with more than half the interior brown

Internal view of a rare speck rot infection of Fuji in an orchard in the Pacific Northwest after heavy rain. Photo: A. Amiri, WSU TFREC.

half an apple, mostly dark gray

Cross section of a speck rot lesion showing black coloration f the internal flesh of Granny Smith. Photo: A. Amiri, WSU TFREC.

an apple, entirely black and covered with small gray spots

Advanced symptoms of speck rot on Granny Smith under high humidity; note abundant pycnidia. Photo: CL Xiao, USDA-ARS.

Phacidiopycnis rot in Pear

This infection in pears is primarily caused by P. pyri and is referred to as Phacidiopycnis rot.

a pear with the upper half brown

Early-stage stem-end Phacidiopycnis rot on a d’Anjou pear. Note the water-soaked appearance. Photo: CL Xiao, USDA-ARS.

a pear, mostly brown with some white spots and black around the stem

The color of decayed area varies with age. Water-soaked at the margin. Black pycnidia at aged area near stem. Photo: A. Amiri, WSU TFREC.

a completely damaged pear with brown and black patches

Advanced stage of P. pyri infection showing black coloration of the decayed area. Photo: A. Amiri, WSU TFREC.

bottom of a pear with damage that is just turning brown

Early-stage of calyx-end Phacidiopycnis rot. Note the water-soaked appearance. Photo: CL Xiao, USDA-ARS.

a pear with damage on the upper portion around the stem

Early stage of stem-end Phacidiopycnis rot on a d’Anjou fruit; watersoaked appearance. Photo: CL Xiao, USDA-ARS.

a damaged pear with color graduating from brown to dark gray

Advanced stage of stem-end rot showing the change in color across the decayed area. Photo: CL Xiao, USDA-ARS.

end of a pear with discolored area around the calyx

As the decay advances, the aging decayed area turns brown to black. Photo: CL Xiao, USDA-ARS.

almost entirely damaged pear, brown and black around the calyx

Advanced stage of calyx-end rot; black at the calyx-end area; pycnidia may form. Photo: CL Xiao, USDA-ARS.

a increasingly brown toward the center spot of damage on a pear

Early stage of wound infection commonly associated with limb rubs or punctures on the fruit created at harvest. Photo: CL Xiao, USDA-ARS.

damage on a pear with a black spot in the center

Phacidiopycnis rot from wound infection; the infection site turns brown to black as the decay advances. Photo: CL Xiao, USDA-ARS.

a pear, green on top and light brown on the bottom with a large chunk of flesh removed

Internal decayed flesh translucent, clear at the margin. Photo: CL Xiao, USDA-ARS.

Washington State University