All about potatoes.pdf - Vegetableipmasia.org

10.
MAJOR POTATO DISEASES
Management
Management should be carried out when this disease is discovered in the vegetative
growth or tuber initiation stages. Infection in the tuber bulking stage does not affect
harvest quality or yield; therefore, it is not economical to manage the disease during
this stage.
Management techniques for this disease include:
• Removing sources of infection, using healthy seed, destroying contaminated
plants and crop rotation.
• Using good irrigation systems to prevent the disease spreading through water.
• Balanced use of fertilizer to produce healthy plants more resistant to infection from
this disease.
• Cutting back stems at 80 DAP, to prevent the disease spreading to tubers.
10.2.3 Fusarium wilt
As with early blight, this disease, causes by the fungus Fusarium spp, is not a major
problem in potato cultivation in the tropical highlands. Attention should be paid when
planting in warm temperatures or in the dry season.
Symptoms
Fusarium wilt affects potatoes in the field and in storage. Affected plants display
spots and yellowing of leaves. It is more of a problem when it infects tubers in
storage. They become dry and hollow, and concentric circles appear on their skins.
Source and spread
The sources of this disease are contaminated soil and other infected tubers. It
spreads via soil, wind or water.
Management
This disease is generally managed in the storage area, where infection is more
damaging than it is in the field. You can control this disease effectively by sorting and
destroying infected tubers in the storage area.
10.3 Viral diseases
A common problem when cultivating potatoes is reduced yield from one generation to
the next. Farmers often consider the cause to be old and degenerated seed
potatoes.
In fact, this yield reduction is caused by viral infections residing in the seed tubers.
These diseases are very varied and display a multitude of symptoms. It is difficult for
farmers to gain an understanding of viral diseases because:
• Their causal agents are tiny and invisible to the eye.
• Viral infections rarely cause plants to become damaged or die. The symptoms
visible, if any at all, are changes in the shape of plants. Consequently, most
farmers consider viral diseases harmless.
• It is difficult to differentiate between symptoms of one virus and another, as they
are all very similar. Thorough testing calls for equipment and expense well beyond
farmers’ reach.
A HANDBOOK TO THE ECOLOGY AND INTEGRATED MANAGEMENT OF POTATO 67