The Potato crop in Pakistan is affected by many pests and diseases. From these diseases potato viruses, powdery scab, potato cyst nematode, aphids and white grub are the most damaging ones. Surveys done by Pakistani workers have revealed that viruses, powdery scab and aphids are wide spread, white grub are serious problems in the northern hilly areas.

Black Scurf (Rhizoctonia solani)

Black Scurf is a fungal disease of potatoes and is caused by Rhizoctonia solani. It is usually found as irregular, black, scab-like marks on the skin of the tubers. They are easily scraped off with a fingernail and this releases a distinctive ‘fungal’ smell. These black masses are the resting phase of the organism and are made up of compacted mycelia, called sclerotia. They do not spoil the flesh of the tubers and they are still edible; also the sclerotia do not become any larger during storage.

Late Blight

Late blight is caused by the fungus Phytophthora infestans. Unlike most pathogenic fungi, the late blight fungus cannot survive in soil or dead plant debris. It is a serious disease and found major yield limiting factor in high hills and is also a serious problem in plains; it may reduce the yield up to 70%. Usually no symptoms appear before the month of December.

Early Blight

Early blight is caused by the fungus Alternaria solani, which survives in infected leaf or on stem tissues or in the soil. This fungus is universally present in fields where Potatoes and tomatoes have been grown. It can also be carried on tomato seed and in potato tubers.

Powdery Scab or Soil Borne Disease

Powdery scab of potato is caused by Spongospora subterranea. Potato cultivars that are susceptible to the disease present sponge-like galls on the roots, stolons and scabby lesions on the tubers. Potato plants that are infected with the pathogen develop necrotic and deformed roots, which may affect plant vigor. The reduction of plant vigor can potentially influence the development of large tubers that are needed for processing.

Recommended Control Measures for Fungal Diseases

  • Wet poorly drained areas should be avoided for potato cultivation.
  • Use disease free seed combined with seed treatment with benomyl.
  • Seed should be planted on raised beds and in well-drained soil to encourage fast growth of the seedlings.
  • Harvest the crop as soon as the tubers are mature, which can reduce the number of sclerotia on tubers. Apply boric acid before storage.
  • Destroy and burn the plant debris before sowing.
  • Harvest carefully to avoid bruises and injuries to potato tubers.

Recommended Control Measures for Bacterial Diseases

  • Use of healthy seed tubers and Cultivation in un-infested fields.
  • Destruction of diseased plant debris.
  • Cultural practices to stop spread.
  • Long rotation and Destruction of host plants etc.
  • Disinfection of seed tubers.
  • Spray


Potato crop matures in 100 – 120 days. Drying of vines, hardening of potato skin and yellowing of leaves are the indications that the tubers have gained maximum size and weight. Potatoes are reaped either using a mechanical harvester or manually using spade for their digging. Tubers if kept under shade for 2 – 3 days harden their skin to avoid its removal during grading and packaging. Tubers are graded for separate packaging of superior grade to get high prices. Potato tubers which are uninjured, clean, dry and free from diseases are packed in clean, disinfected and unspoiled bags. Potatoes to be kept for seed purposes are stored at 3-4°C while the ones to be marketed after 2-3 months can be stored at 10 – 15°C.

Poor post-harvest handling, including transport and storage practices, causes unnecessary damage and losses and reduction of consumption quality. Sufficient cold store space is available in Pakistan. The handling of potatoes in storage is unsatisfactory and poorly managed. Finally, the farmers and consumers are faced with serve cyclical fluctuations in price, as production moves from glut to shortage, so preventing the farmers from enjoying a reliable income and inhibiting the consumer from including potato as a regular staple part in his diet.


The average yield of potato is 20-30 tons/ha, however it depends upon the variety, cultural practices, and location.


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