Potato

• Fusarium dry rot
• Bacterial soft rot
• Late blight
• Pink rot
• Leak

• Early blight
• Black dot
• Silver scruf
• Rhizoctonia
• Common scab

• Powdery scab
• Potato tuberworm
• Flea beetles
• Wireworms
• Root knot nematode

• Leafroll net necrosis
• Thumbnail cracks
• Shatter bruise
• Blackspot bruise

Fusarium dry rot
Identification tip: Dry, wrinkled lesions on the tuber surface; white or pink mold often develops; underlying rotted tissue dry, unless invaded by bacteria.

Bacterial soft rot
Identification tip: Lesions with distinct, dark margins; rotted tissue tan or cream colored and soft.

Late blight
Identification tip: Brownish purple areas with black margins on tuber surface; underlying rotted tissue coppery brown, granular, lacking distinct margins.

Pink rot
Identification tip: Rotted tissue with distinct, dark margins; decayed tissue firm, turns pink then black when exposed to air.

Leak
Identification tip: Rotted areas with distinct, dark margins; decayed tissue spongy, wet, may turn pink; eventually turns dark gray.

Early blight
Identification tip: Tuber lesions dark brown and sunken; underlying tissue brown, corky, and dry.

Black dot
Identification tip: Gray patches on the tuber surface similar to silver scurf; tiny black dots within lesions distinguish black dot from silver scurf.

Silver scurf
Identification tip: Light brown or grayish, leathery, shiny patches on tuber surface; lesions may turn dark and sooty.

Rhizoctonia (black scurf)
Identification tip: Hard, irregularly shaped black flecks in the surface that do not penetrate the skin and are not easily rubbed off.

Common scab
Identification tip: Irregularly shaped lesions in patches with dark brown, corky tissue; may appear raised above the tuber surface or as sunken pits.

Powdery scab
Identification tip: Dark, pimple- or wart-like pustules about 1/8 to 1/4 inch in diameter.

Potato tuberworm
Identification tip: Holes in tuber surface and tunnels in tuber flesh filled with dark excrement.

Flea beetles
Identification tip: Pimples on tuber surface; small, brown tunnels penetrating up to ¼ inch into tuber flesh.

Wireworms
Identification tip: Shallow to deep holes in tubers lined with skin; excrement not present.

Root knot nematodes
Identification tip: Irregular bumps or warts on tuber surface sometimes present; brown spots in tuber flesh, mostly in the outer 1/4 inch.

Blackspot bruise
Identification tip: Small to large, dark discolored areas underneath tuber skin; damage usually not visible unless potato peeled.