POTATO PROFILE

INTRODUCTION

Botanical Name: Solatium tuberosumlj.

Family: Solanaceous.

The Potato (Solanum tuberoswn L.) belongs to the family Solanaceae. There are many related species, but only the potato and a few others bear tubers. Potatoes are an important staple food crop. Annual world production of potatoes surpasses that of all other vegetables and ranks with wheat and rice. Introduced into Europe in the 16th century by Spanish explorers, it is cultivated throughout the world including the Indo-Pakistan subcontinent. Potatoes are used alone and mixed with meat, fish, chicken, and vegetables, & in big cities and towns, potato chips are prepared and sold commercially. The potato is rich in starch and contains protein, minerals, & a fair amount of vitamins, particularly Vitamin – C.

CLIMATE

The potato has a wide range of seasonal adaptability. It is a cool season crop and is moderately frost – tolerant Temperature during the growing season has long been recognized as one of the most important factors influencing yield. Young plants grow best at a temperature of 240C; later growth is favored at 180C. Tuber production reaches a maximum at 200C, decreases with rise in temperature, and at about 300C tuber production stops entirely. Short days are beneficial for tuber production.

SOIL

The potato develops best on deep, fertile, sandy lo clay loams with good water retention capacity. Because the potato has a relatively weak, shallow root system, impermeable layers in the soil limit rooting depth, which restricts water availability to the plant in dry. periods. Thus soil compaction can greatly reduce potato yields. Aeration of the soil has a great effect on the set and development of tubers.

MANURES AND FERTILIZERS

Potato has a high nutrient requirement; a yield of 25 tones of tubers/ha depletes the soil of 119 kg of N, 50 kg of P and 225 kg of K. In light soils and places where organic manures are not easily available, green manuring is beneficial. Well rotted FYM at 30 t/ha should be incorporated into the soil three to four weeks before planting. Research on fertilizer requirements conducted in the Punjab and Sindh suggests that 100 kg N, 80-100 kg of P2O5, and 50 kg K2O per hectare are sufficient- to obtain good yields.

SPACING

Li hilly areas, potatoes are spaced at 60 x 30 cm and the tubers are planted in furrows. In the plains, however, they are planted on ridges spaced 30 cm apart; the distance between ridges is kept at 45-60 cm.

SEED RATE

Potatoes are propagated by tubers, planted either whole or cut into pieces. To obtain maximum yields, healthy, disease-free tubers, free from mixture of other varieties, should he use. Seed rate depends on tuber size; 800-1000 kg/ha is generally recommended. Choudhary et al (1990) conducted a trial comparing improved seed of the Swat and Kaghan varieties brought from the Kaiam Integrated Development Project with seed from the local market. Potatoes grown from the improved seed gave better soil coverage, had a lower incidence of virus attack and higher tuber weight and gave higher yields than those from the locally purchased unimproved seed.

IRRIGATION

Potatoes need frequent irrigation. The first irrigation should be given immediately after sowing, and thereafter at one week intervals. After tuber formation, the frequency of irrigation is decreased. Care must be taken while irrigating that the water does not reach fee top of the ridge. Irrigation should be stopped a few days before harvesting.

HARVESTING

The size of the tuber increases until the vines become dry. In developed countries, potatoes are harvested by mechanical harvesters. In Pakistan, they are manually harvested by digging up the ridges with a spade. Care must be taken that tubers are not injured during the process. After harvesting, the crop should be kept in the shade.

YIELD

The average yield of potato is 20-25 tonnes/ha, however it depends upon the variety, cultural practices, and location.

VARIETIES

Kufii Sindhuri, Kufri Chandramukhi, Kufri Jyoti, Kufri Dewa, Kufri Babar, Kufri Lalirna, Kufri S \vaina, Kufri Megha, Kufri Ashoka, Kufri Jawahar, Kufri Sultej

DISEASES AND PESTES

DISEASES

Non-Viral Diseases

  1. Early Blight (Alternaria solani)

The infection appears on lower .leaves with necrotic spots having concentric rings. The fungus survives in the soil. In diseased plant debris. The collateral host is tomato. High moisture and low temperature are favourable for disease.

Control Measures

  • Follow crop rotation
  • Collect and bum plant debris after harvesting
  • Start sprays the crop Dithane M-45 at 0.2 per cent 30 to 35 days after planting and repeat I0 to 15 days interval
  • Grow early blight tolerant varieties such as Kufri Naveen, Kufri Sjndhuri and Kufri Jeevan.
  1. Late Blight (Phytophthora infestans)

The infection appears at the tips or edges of the lower leaves with circular or irregular water soaked spots. White downy fungus growth appears on the underside of the leaves around the spots. Cloudy weather is conducive for very fast spread of the disease. In case of sever incidence all above ground parts may show rotting. Later the disease may spread to tubers and initiate rotting.

Control Measures

  • Plant only healthy disease free certified seed tubers.
  • Spray the crop thoroughly with diathane M-45 (2.0 kg/ha) or diathane Z- 78 (2.5 kg/ha) or difolatan (2.5 kg/ha) well in advance to general appearance of disease. The spraying operations should remain continue at narrow interval of 5 to 6 days during cloudy weather.
  • Dig out tubers when foliage is completely dry or cleaned.
  • Grow late blight resistance varieties like Kufri Navaharl.
  • Avoid applying in excess nitrogen and irrigation.
  1. Black Scurf (Rhizoctonia solani)

The infected plants killed, stem canker may also be formed. Affected plants may form aerial tubers. On tubers, black sclerotial bodies are formed. It is a soil as well as tuber borne disease.

Control Measures

  • Always sow certified seeds
  • Treat the seed tubers with any organo mercurial fungicides containing 6 per cent mercury {agallol, aretan, emisan etc.) for about 5 to 10 minutes before the planting and also seed tubers before keeping in the cold storage.
  • Dip the tubers in 1.75 per cent solution of sulfuric acid for 20 minutes.
  • Apply Brassicol at 30 kg per hectare in the soil at the time of sowing.
  • Apply sawdust at 25 q/ha with recommended doses of nitrogen at least 15 days before sowing.
  1. Common Scab of Potato (Streptomyces scabies)

It survives in soil years together and on infected tubers in cold storage. It may also spread through manure. Affected tubers show the superficial roughened areas of corky tissue, often slightly below the plane of healthy skin of tubers. Low soil moisture is favourable for proliferation of causal pathogen.

Control Measures

  • Obtain healthy, disease free seed tubers for planting.
  • Disinfect the tubers by dipping in suspension of mercurial fungicide e.g. emisan-6 or agallol- 6 at 0.25 per cent concentration for 5 minutes,
  • Plant the tubers shallow.
  • (IV) Keep the soil wet during tuberization.
  • Follow crop rotation with non-host crops including beets, carrot etc.
  • (VI) Maintain soil pH 5.0 to 5.3.
  1. Black Leg or Soft Rot (Erwinia spp.)

It is caused by different species of bacteria. The base of shoots develops a blackened shriveled cortex and its growth is stunted. Leaflets become reddish in colour at the tips, branches become stiffened and more upright than normal. The affected haulms are jet black in colour at the soil level. The tubers become watery and upon rotting give off offensive sulphurous odour.

Control Measures:

  • Obtain healthy seed tubers for planting.
  • Avoid planting of cut seed potato.
  • Avoid planting too early and too late in the season.
  • Collect and destroy affected plants as and when seen in the field.
  • Avoid injury to tubers during harvesting, transit and storage.
  • Wash the tubers with chlorinated water before storage.
  • Keep the stores well ventilated, dry and cool.
  1. Bacterial Brown Rot or Wilt Disease (Pseudomonas solanacearum)

Affected plants show dwarfing and bronze discolouration of the leaflets. When affected stem or tubers cut across, the browning of the xylem vessel is seen, and upon squeezing, the whitish bacterial ooze may come out.

Control Measures

  • Obtain healthy, disease free seed tubers for planting.
  • Collect and destroy infected plants.
  • Avoid flowing rain or irrigation water from diseased field to healthy one.
  • Disinfect cutting knife with a suitable bactericide solution, whenever diseased tubers are cut.
  • Follow crop rotation with non-host crops such as maize, soybean and red top grass for at least three years in the field,
  • Reduce the application of organic manure (it promotes activity of bacteria) but apply high doses of inorganic fertilizers (decrease the activity).
  • Treat the seed tubers in 0.02 per cent sueptocycine for 30 minutes after giving five mm deep cut.
  1. Charcoal Rot (Macrophmina phaseoli)

The roots of the affected plants become brown in colour. The rotting starts on the stem portion. The skin of the stern becomes ash coloured.lne dark lesions appear at the lenticels of the tubers and also round the stern end of tuber. Charcoal rot is common during the hot and dry months in late season crops.

Control Measures

  • Obtain disease free seed tubers for planting. Hill potatoes are nearly free from this pathogen.
  • Grow early maturing varieties such as Kufri Alankar or Kufri Chandramukhi.
  • Irrigate crop at regular intervals.
  • Seed tubers may be treated with ageUal-6 or aretan at 0.25 per cent solution before storage. The treated tubers should not be eaten.
  1. Wart Disease of Potato (Synchytrium endobioticum)

It is a caused by the fungus. Affected plants show warty out growth protuberances on sterns, stolons and tubers. The roots are not affected. The wart consists of distorted, proliferated-branched structures grown together into a mass of hyper parasitic tissue. It is difficult to control once it has been established in a field.

Control Measures

  • Avoid growing potatoes in known wart-affected soil.
  • Obtain disease free seed tubers for planting.
  • Soil treatment with 5 per cent formalin is effective but very costly.
  • (iv)Grow wart tolerance varieties like Kufri Sherpa, Kufri Jyoti, Kufri Jeevan and Kufri Muthu.

Viral Diseases

1.Leaf Roll

A virus known as potato leaf roll virus, potato virus 1, solanum virus 14 or Corium solani Holmes causes it. Transmission of virus in nature occurs through infected tubers and through insect, an aphid (Myzus persicae). Affected plants become dwarf, more upright thin normal, the leaves are rolled, especially the lower one. They are thick and leathery. Mosaic Disease Potato crop is affected by mainly three types of mosaic. Type of mosaic Caused viruses Mild mosaic- Potato Latent virus, Potato Virus X, Potato Mottle Virus, Solanum Virus-l. Rugose mosaic -Potato Virus X and Potato Virus Y . Cinkle of potato- Potato Virus X and Potato Virus A

Control Measures of Potato Viral Diseases:

  • Plant only certified seed tubers
  • Apply anyone of the systemic insecticides like thimet, temik or furadan in the furrow at 10 kg per hectare at the time of planting
  • Uproot affected plants along with complete root system and mother tuber, and destroy them
  • Spray the crop with metasystox at 0.1 per cent to control aphid population
  • Remove haulms in the first week of January, when aphid population build up is very fast.
  1. Phytoplasma Diseases

Potato Witches Broom Infected plants develop many axillary and basal shoots giving ‘witches broom’ appearance and develop small, pigmented tubers. These tubers sprout even attached to infected plants (Nagaich et al., 1974). The disease is transmitted by grafting and leafhopper

  1. Orosius albicintus

Tuber transmission is also very high. The pathogen can infect tomato, brinjal, Datura , D. metel, Nicandra physaloides, Vinca rosea and Calendula officinalis. This disease can be controlled by hot water treatment of ‘witches broom’ affected tubers at 50 °C for 10 minutes, causes degeneration of pathogen and plants developed from such tubers did not develop symptoms upto 6 to 7 weeks.

  1. Purple Top of Potato

The typical symptoms are purple pigmentation and rolling of basal parts of leaflets of young top leaves. The affected plants are stunted have many axillary shoots with aerial tubers. Root system is poorly developed (Nagaich and Giri, 1973). It causes phloem fluorescence. The disease is transmitted by grafting and leafhoppers (Alebroides nigrocutellatus, Orosius alibicinctus (and Seriance equata), Tuber transmission is also common but the extent varies with age of plants, the host range of pathogen includes tomato, tobacco, brinjal, clove, Datura stramonium, Calelldula officinalis, Cyphomandra betaceu etc, Phyalis floridana, Vinca rosea, Oxytetracycline, benlate, cycloheximide etc. are highly effective and causes 70 to 96 per cent remission of symptoms. Marginal Falvescence of Potato Flavescence or chlorosis along the margins of leaflets of upper leaves and small, narrow leaflets are prominent symptoms, affected plants are stunted and produce clusters of small tubers, which have shorter dormancy and produce hairy sprouts. It causes phloem fluorescence (Nagaich and Giri, 1973). The disease is transmitted by grafting and hopper, Seriana equate the disease can infect other hosts like, tomato, tobacco, brinjal, calendula officinalis, physalis flloridana, vinca rosea, and cyphomandra betacea. Treatment of affected plants with antiamoebin + benlate or benlate + BP causes remission upto 80 per cent.

  1. Potato Phyllody

The disease is characterized by extreme hairiness and roughing of leaves and stems. Chlorotic leaves develop small leaflets but enlarged petioles. Infected plants develop several naked androecia as small yellow “rosettes” and axillary aerial tubers Phyllod flowers are enlarged and have cupped clays and corolla (Khurana et al 1983). It has wide host range and includes Dianthus barbatus, Pisum sativum, Lycopersicon chilense, Phyalis floridana, Solunum nigrum and Daucus carota. The pathogen can be eliminated by subjecting infected tubers to hot water treatment at 50 °C for 10-15 minutes.

PESTS

  1. Cut Worms (Agrotis spp, Euxoa spp)

They cut the sprouts at ground level. They feed only at night. They also attack tubers and make holes, thereby reducing market prices.

Control Measures

  • Spray the crop with dursban 20 EC at 2.5 ml per litre of water or drench the plants, where the damage is noticed.
  • Apply phorate 10 G granules at 10 kg I per hectare on soil around the plants and rake the soil thereafter.
  • Use only well rotten farmyard manure.
  1. Epilachna

Beetle Both the adults and larvae of this beetle feed on skeletonization of leaves.

Control Measures

  • Pick up the eggs, larvae and adults by hands.
  • Spray the crop with carbaryl at 0.1 per cent.
  • Dust the crop with sevin dust at 30 kg per hectare.

 

  1. Leaf Eating Caterpillars (Spilosoma obliqua, Spodoptera exigua)

Both the caterpillars cause damage by feeding potato leaves.

Control Measures

  • Spray the crop with thiodon 35 EC or endocel at 0.15 per cent
  • Making border around the field with carbaryl dust would be effective control. Aphids (Myzus persicae) Aphids sucks the sap from leaves. Affected plants become weak, leaves become yellow and curl downwards.

 

  1. Aphid

Secretes honeydew, which gives rise to sooty mould and other fungal diseases.

Control Measures

  • Spray the crop with rogor or metasystox or nuvacron or monocil at 1 ml per liter of water, and repeat the spray 10 to 12 days interval
  • Apply thimate 10 G granules at 10 kg per hectare in furrows at the time of planting.
  • Cut the haulms in the first week of January to check the transmission of virus through seed potatoes.

 

  1. Jassids

They are slender wedge shaped green hopping insects. They are diagonally. They suck sap from under surface of leaves causing yellowing, curling and later burning of leaves called ‘hopper bums’

Control Measures

  • Spray the crop with metasystox at 0.1 per cent.
  • Apply thimet 10 g granules at 10 kg per hectare in furrows at the time of planting.

 

  1. Potato Tuber Moth (Phthorimaea operculella)

It is major pest of potato in storage. It can also attack in the field. It bores and makes tunnel into the potato tubers.

Control Measures

  • Sow healthy insect free potato tubers.
  • Use only well rotten farmyard manure.
  • Do earthing carefully, so that tuber is not exposed in the field to ovipositing female moths
  • Spray the crop with carbaryl or nuvacron or monocil at 0.1 per cent.
  • Disinfect the go down with Malathion at 0.05 per cent before storing potatoes.
  • Sort out all affected tubers before storage.

 

  1. Golden Nematode (Globodera rostochiensis, Heterodera rostochiensis)

It is also known as potato root ell worm or potato cyst nematode. The infected plants produced additional rootlets near the soil surface. Later, outer leaves become prematurely yellow and die.

Control Measures

  • Keep the infested area in quarantine to prevent the spread
  • Avoid growing tomato or brinjal in infested soil.
  • Follow crop rotation excluding solanaceous crop.
  • Treat the soil with DD at the rate of90 gallons per hectare.
  • Avoid the soil seed tubers brought from infested area.

 

  1. Root Knot Nematodes (Meloidogne incognita and M. ja avanica)

Affected plants are stunted, sickly and may show premature and sudden drying. Tiny galls are formed on tubers. The nematodes survive as egg masses in diseased root and tuber in soil.

Control Measures Similar control measures as described in tomato