Now that the frost prone period is gone, it is advisable to start planting potatoes as early as possible, because you do not only escape frost and late blight attack, but your yield potential is marginally the highest of all the 3 planting seasons.
Compiled by Tapiwa Mugabe – Agronomist Agri-access (Pvt) Ltd
By delaying your planting from now you increase your chance of late blight and other disease susceptibility; as the weather will become more conducive for disease spread ie. Hot and humid. However, when you plant now you need to be alert for potato tuber moth, because they can be high during this season. For control of potato tuber moth you can use carbaryl and monocrotophos.
Potato Tuber Moth
True Potato Seed
The major challenge being faced by many aspiring potato farmers is the prohibitive cost of the seed (tubers). There is now a company in Harare called EDDA Seeds which is now supplying True Potato Seed (TPS). This is real potato seed and not tubers. This is currently being imported from India. On establishing the crop out of TPS, you make seedbeds just as you would do with tobacco seedbeds and then after 4 to 6 weeks your seedlings will be ready for transplanting. 1 x 30m bed will be enough for a ha. In the lands the crop will take between 90 to 120 days depending on the variety. The seed actually cost less than half the cost of Tuber Seed. Currently, TPS is being sold for $800/ ha plus $200 for agronomy and assistance in establishing the crop, making it a total of $1000/ha. If you were to purchase tubers, you need to budget on around $2200/ha. I personally still need to verify the yield potential of these varieties, because some farmers have and extension officers have told me that the yield is not comparable to tuber seed potatoes. In actually fact the yield is incremental as you retain seed up to a certain level then it begins to decline. What that means is that you will realise a higher yield as you retain your seed tubers once or twice. I will keep you informed on the performance of these varieties.
True Potato Seed
Some of the advantages of this TPS are:
1. It is cost effective
2. It is transport convenient. You need 100g per ha
3. You can retain your seed for 2 or 3 seasons
4. Some frost tolerant varieties are available.
This another way of reducing the cost of seed. However before dwelling much on this type of seed production, one should be fully aware that the major success factor of this type, is good hygiene. With this type of seed production, large tubers are cut into small “cubes”. These cut tubers should have at least 2 eyes or shoots. When cutting the tubers, all cutting utensils should be disinfected in a sterile solution, during the cutting session, such as formalin to avoid diseases spread. After cutting, the tubers should then be dipped in a fungicide such as Bravo to help protect the cut tuber from fungal attack. The cut tuber should be stored for at least 10 to 14 days at 7-18oC and as near 100% humidity to encourage formation of the suberin layer (protective layer) over the cut surface. It is important to observe every process stated above, because a deviation or ignoring certain points stated above will result in losing the benefits of using this type of seed. This type of seed production is widely being used in countries such as China, but is not common here in Zimbabwe.
There is always an argument around the agric circles that “ don’t we need new strain or new potato varieties in our local Zimbabwean market”. This is because over the years our own varieties have been realising diminishing returns in term of yield. While we struggle to achieve 40T per ha, other countries like Kenya are talking of 80T/ha and more. Is it because there is no constant research and development going on concerning potato varieties? Why not go ahead and try the new varieties and rate them against your conventional varieties.