Diseases of Potatoes: Non-Infectious

Blackheart
Low oxygen

What to look for?
Tuber discoloration occurs when the soil becomes waterlogged in the growing season or the tubers are deprived of oxygen in storage.

Photo: Evans

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Brownheart
Low oxygen

What to look for?
A variation of blackheart, again generally caused by oxygen deprivation in storage.

Photo: Evans

Growth Cracks

What to look for?
Extreme moisture changes causes malformed tubers. Potatoes grown under very dry conditions may liquify when boiled in water, forming a clear translucent yellow liquid. Additionally growth cracks may be induced by soil persistent herbicides or infection by Rhizoctonia solani.

Photo: Ormrod

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Hollow Heart

Photo: Evans

Picture description
Rapid tuber enlargement forming a star-shaped cavity. Ideal growing conditions.

Photo: Howard

Picture description
Necrotic and hollow tubers as a consequence of an irregular water supply.

Herbicide Damage

What to look for?
Amitrol can cause tuber malformation as a consequence of soil-borne residues.

Fiddle heads form in response to soil-borne residues of this phenoxy herbicide. Potatoes are extremely sensitive to this herbicide at concentrations below 1 part per billion. Spot weed treatments around farmsteads using Picloram over 30 years ago show up clearly in potatoes planted in the contaminated soil.

Photo: Evans

Picture description
Tuber malformations (Amitrol)

Photo: Evans

Picture description
Fiddle heads (Picloram) can be carried in healthy appearing tubers grown in contaminated soil

Secondary Tubers
Cold, dry soil

What to look for?
Tubers formed from sprouts in Russet Burbank under very cold soil conditions close to freezing. Tuber will then go dormant and no shoots will appear.

Photo: Evans

Picture description
Tubers formed from sprouts in Russet Burbank

Photo: Evans

Picture description
Tubers may also be formed in clusters under very cold soil conditions eg. Norland. No shoots will appear above ground.

Pigmentation
Physiological

What to look for?
Remember potatoes can be white yellow, pink, red or purple fleshed as well as having the aforementioned skin colors.

Photo: Evans

Picture description
Internal coloration that can occur in some cultivars such as White Rose.

Photographs and information assembled and prepared for ARD by Dr. Ieaun R. Evans Agri-Trend Agrology Ltd.

For more information about the content of this document, contact Robert Spencer.
This information published to the web on December 1, 2003.
Last Reviewed/Revised on April 7, 2014.