Stem Rot Potato disease « POTATO DISEASES

Stem Rot Potato disease

Thursday, September 10th, 2009

(Sclerotium rolfsii)

Stem rot, southern blight, or Sclerotium rot occurs worldwide and attacks a wide range of potatoes plants, but is a problem for potato only while growing under hot, moist conditions.

Symptoms of Stem Rot

Initially, daytime wilting and yellowing result when brownish lesions girdle the stem base just below the soil line.

A white mycelium grows on potatoes stems, tubers, or soil, often in fan-like mats, which produce small, initially white, but later brown, sclerotia, similar in appearance to mustard seed.

stem-rot In rainy weather, the affected stem sloughs off, leaving only the vascular tissue of the xylem, which leads to stem collapse.
Potato tubers may rot in the field before harvest, in storage, or in transit. They first form a cheesy semi-firm decay, which is often invaded by soft rotting organisms. Seed tubers may decay before plant emergence.

Management

Sclerotia are long-lived and many crops are susceptible to S. rolfsii.
Control of stem rot is difficult when conditions favour disease.

Either plow deeply to bury affected plants and crop residues or remove them from the field and burn or bury them.
Avoid plant debris around potato stems.

The pathogen is highly aerobic; therefore, deep plowing and rotation with paddy rice are effective.
Harvest potatoes during dry weather.
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Tags: management, pathogen, POTATO DISEASE, rotation, Stem Rot, symproms

POTATO DISEASES