All about potatoes.pdf - Vegetableipmasia.org

10.
MAJOR POTATO DISEASES
o In their early growth phase, plants grow rapidly and systemic fungicide can
spread into new tissue, thus protecting all parts of plants from early infection of
late blight.
o Spraying during the early growth stage only requires a small amount of
fungicide and minimal cost.
o Systemic fungicides can also control late blight carried by seed potatoes.
How to increase effectiveness of initial fungicide application:
• Try to ensure plants reach their early growth stage simultaneously. Uniform
growth will improve fungicide use effectiveness. You can achieve this by:
o Making good seed beds.
o Planting at a uniform depth.
o Using good quality seeds. Good quality seeds are characterized by uniform
shoot length.
o Using proper equipment - Choose a small spray nozzle, so the liquid sprayed
sticks easily to all parts of the plants.
o Using clean water - It is best not to use dirty water when making fungicide
solutions.
o Fungicides should evenly coat the tops and bottoms of leaves.
Appropriate doses
Recommended dose for most fungicides is 2.5 g fungicide/liter of water. This is a
general recommendation; however, to use appropriate amounts, you should look at
the recommended dose mentioned on the packaging. For example, fungicides with
the active ingredient fluazinam are used in lower doses.
B. Reducing the spread of the disease
There are four factors to disease development capacity:
• The efficiency of agents causing the disease.
• The development stages of the disease from initial infection to producing spores.
• The development level of lesions.
• The capacity to form spores (per unit area).
Farmers should understand the factors influencing the development of this disease,
at least at a conceptual level, because this knowledge is the foundation for
developing management techniques. Modifying one factor will change disease
development. Techniques that can be implemented are described in the following
sections.
B.1. Use of fungicides
Contact fungicides can reduce infection and influence the formation of spores and
the spread of rot on the leaves. With the first application, farmers must decide when,
what with, and how much?
Fungicide application times
This is very difficult to get right, especially in terms of optimizing fungicide use,
because of how it relates to other factors.
• Make regular observations (at least 3 times a week) by looking for symptoms of
the disease. Base observation intervals on your experiences with the way this
disease develops. Appearance of symptoms can be your sign for applying
systemic fungicide.
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ALL ABOUT POTATOES