All about potatoes.pdf - Vegetableipmasia.org

9.
DISEASE ECOLOGY
• The environment supports the development of the pathogen, for instance:
o Suitable temperature and relative humidity for disease development (often high
temperatures and high humidity).
o The presence of pathogen carriers, such as wind, water, farming tools, insects,
etc.
These three factors are related to each other as depicted in the so-called disease
triangle (see Figure 3).
Disease source
Environment
Host plant
Figure 3: The disease triangle
A disease management strategy can be designed by influencing or changing any one
of these factors of the disease triangle, and hence obstructing disease development,
for instance in the following ways:
Influencing the DISEASE SOURCE by:
• Reducing the presence of diseases in the field by carrying out sanitation,
destroying infected plants, selecting disease-free fields, using clean water for
irrigation and using disease-free seed.
• Breaking the disease chain by rotating crops.
• Using composted organic fertilizer, which increases the quantity and role of living
organisms that can combat diseases, and does not introduce disease causal
agents.
Influencing HOST PLANT health by:
• Using healthy seed to produce a homogeneous, healthy crop.
• Providing balanced fertilization and using composted organic fertilizer to promote
plant health.
• Using resistant varieties where possible.
Influencing and changing ENVIRONMENTAL conditions by:
• Planting potatoes at the end of the rainy season or at the end of the dry season,
so the weather is drier and less suitable for disease agents to develop (note: this
refers to wet tropical highland conditions).
• Making seedbeds higher in the rainy season so the soil is not too wet or moist.
• Adjusting planting density as to reduce humidity around the foliage during the wet
season.
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ALL ABOUT POTATOES