Irish Potatoes

Land preparation is done as follows:

• First ploughing when the land was furrowed,
• In case it is not furrowed, plough well and remove weeds,
• Second plough round before planting;
• Leveling the land before making rows or holes;
• Make planting holes which are 5 to 10 cm deep.

Potato seed

Potato seed must:

Be disease free

Be free from any defect,

• Have middle size 25-55 ml of diameter),
•  Have sprouted enough ( 3-4 sprouts),
• Be selected and certified,
•  You can buy potato seed from a nearby seed multiplier or agro dealer.

This picture portrays well sprouted potato seed

N.B: you have to change the seed at least after four times if you are using the seed from the one you bought.

• Planting time: potatoes are planted in September for Season A and the second half of February or first half of March for season B, following how it rains.

 

• Planting practices

• On one 1ha, use 2 to 2,5 tons of seeds,
• Spacing: 80cm between rows and 30 cm between holes;

• Prior to planting, apply farm manure and NPK 17 17 17 in planting holes and blend them with the soil. Plant 1potato per hole (8 to 10 cm deep) with sprouts facing upwards. Cover the potato seed with  soil since irish potato is a tuber of the same family as sweet potato, cassava, taro and yam.

Fertilisation

• Apply 20 tons of organic manure per ha while ploughing;
• The manure is applied in rows or planting holes;
• Add 300 kg of NPK 17.17.17 per ha in the seed holes while planting, or 150 kg while planting and the remaining 150 kgs are applied while weeding;
• On acid soils ( Nyamagabe, Nyaruguru and other acidic soil regions), apply 2,5 to 5 tons of lime. This lime has residual effects for four farming seasons.
• Weeding
• Weeding is done after two to three weeks after the seedlings have come out and averagely reached 10 cm of height.
• Weeding helps potatoes to evenly share minerals, water and light as it removes all weeds which would compete with potatoes.
• N.B: While weeding, the farmer makes efforts to do it carefully so that he/she does not wound tender roots of potatoes.
• Ridging
• Ridging s done when potatoes have reached 20 cm of height. The farmer brings the soil closer to the plant but does not cover the potato plants;
• Ridging helps  potatoes to grow well, to  keep its color and to resist to late blight disease.

• Pests, diseases and weeds are factors which significantly reduce potato yield.
• It is necessary to fight against pests, diseases and weeds which can reduce the yield up to 100%.
• Diseases are many and vectors differ. We can mention the following pests and diseases.

Ifoto igaragaza indwara y’imvura

• Mildew is caused by a fungus called Phtophtora infestans. It is frequent in rainy seasons.
• The disease attacks leaves, stems and even the tubers.
• Affected plants leaves get brown, and later on, die.

Means of fighting against the disease:

• Plant resistant varieties and non contaminated seeds;
• All potatoes must be removed from the field at the harvest;
• Uproot any potato plant available in the field, since it could constitute a source of the disease,
• Ridge properly the potatoes.

During rainy and wet seasons:

• When the plants are still young, the farmer may applies Ridomili (50 gr for 20 L of water).

Two weeks later:

• One a week, apply dithane of Mencozeb (50 gr for 20 L of water) on leaves.
• Rotate potatoes with other plants from other plant families.

Potato bacteria wilt

Picture showing potato bacteria wilt

• This disease is transmitted through a bacteria called Pseudomonas solacearum which comes from the soil or poor quality seed;
• The disease attacks leaves and tubers;
• It is characterized by fading of leaves and stems which dry out, the leaves become green and a white liquid comes from the tubers;
•  A cut tuber reveals grey circle inside.Means of fighting against the disease:
• Use safe seeds from resistant varieties;
• Rotate potatoes with other plants from other plant families
• Uproot the seedlings attacked by the disease which could be present in the field.

Potato tuberworm moth

• Potato tuberworm moth: This disease is transmitted by one insect of butterflies family called “Phthorimaea operculella”;
• Its larva dig galleries in the veins of leaves that get brown;
• These insects severely damage tubers (potatoes);
• This is remarkable by galleries made by the insects and by blackish excrements of the same insects;
• Insects damages from the fields may continue their harmful action on the production in storage.

Means of fighting against the disease:

• The farmer is recommended to plant clean and disease free potato seeds and use Deltamethrine or Cypemethrine as prevention treatment.

• Potatoes are harvested after 100-120 days depending on planted varieties;
• When potatoes are ready to be harvested, their leaves become yellowish and vines dry up and fall.
• Before potatoes are harvested, the farmer has to dehaulm them.

• Vines are carefully uprooted so as to leave the potatoes in the soil and enable their skin to be strong enough. Those potatoes are harvested after 2 to 3 weeks,
• Harvest potatoes when the weather is good,
• Potato harvesting is done by hands when the soil is soft or a hoe but it is carefully used so as avoid to wound the potatoes. Harvest can also be done using an appropriate machinery,
• Avoid wounding potatoes while harvesting and remove all of them from the field;
• Remove diseased or infected potatoes from the yield.

Potatoes which remain in the field can host pests and diseases in the next farming season in case they are not killed by the weather.

• Potatoes which are meant for seeds are stored in a dry place with light.
• Potatoes which are meant for consumption are stored in a dry place with no light.
• A farmer is recommended to frequently visit potatoes in the store so as to remove those which are rotten or those with an kind of defect;
• Potatoes are stored following their varieties, it is not recommended to mix them up.