Papaya is eaten as fresh fruit. It is a rich source of vitamin A (2020 IU per 100 g) and sufficient vitamin C (40 mg/l00g). It also contains sufficient amount of Calcium and other minerals. The yellow colour of the pulp is due to caricaxanthin. Papaya contains vitamin By, 100 gm of pylp riboflavin 250 mg 100 gm of pulp, 0.6% proteins and 9% of carbohydrates. It contains papain a protein digesting enzyme. Papain is prepared by collecting latex from the unripe papaya fruits. Unripe fruits can be used as vegetable. Ripe fruits are used for making of Jam, Jelly, and Ice-Cream, etc.
papaya (Carica papaya)
Papaya originated in tropical America.
Climate and Soil:
The papaya being tropical crop favours high temperature and high humidity. It is very susceptible to frost and hail storm. The long days are favourable for good quality and flavour. During flowering, high rains are injurious and cause heavy damage.
The papaya grows under wide types of soils. However, very shallow and very deep black soils are not suitable medium, fertile, well drained and lime free soils are preferred for papaya cultivation.
Commercially the papaya is propagated by seeds. The tissue culture technique is limited to research laboratories only. The seeds loose viability in a short period and therefore the seeds should not be stored for more than a season. The seedlings in polybags are prepared. Due care is taken to avoid damping off of the newly germinated and young seedlings. The seedlings become ready for transplanting within 6-8 weeks.
Planting and Season:
Planting is done during the flowering seasons:
Spring season (February – March)
Monsoon season (June-July)
Autumn season (October-November)
Heavy rains, hot air, frost, etc are considered while selecting the season for planting in a particular area. The pits of 30 x 30 x 30 are prepared in already selected and prepared field at the distance of 2.5 to 3 meters distance. The pits are fitted with well-decomposed FYM and NPK mixtures. A care is taken not to disturb the roots while transplanting the seedlings.
Interculturing is mainly done to remove the weeds during the early period of growth, weeding and hoeing in between rows also favour better aeration to root zone. Some times pre-emerging weed killer like Basalin is used. Secondly, roughing is done to remove extra plants, weak plants and affected plants. After ensuring one plant per pit, earthing up is done 30 cm in radius around the plants.
Special Horticultural practices
Planting of 3 to 4 seedling at one pit and then removing extra plants and keeping one plant per pit while doing so 10 percent male plants are kept in female plant population to have pollination and to improve the fruit
For better growth, production and quality, the optimum soil moisture is maintained by irrigating the crop judiciously. Irrigation interval well depend on season, crop growth and soil type. In no case, water should be allowed to stagnate causing root and stem rot. Drip system of irrigation is beneficial and the actual quantity of water to be given per plant per day should be worked out critically.
manures and fertilisers
The papaya is a very feeder and requires the application of chemical, organic and biofertilisers. The dose of NPK @ 500 kg each per ha, along with 20-25 tonnes of FYM 50 to 100 kg of ormichemi mirconutrients and ultrazyme sea weed extract granules. 25 kg is found for a crop of about 50 tonnes within 18-20 months. Additional 60% of this dose is again applied for the second flush.
Weeding should be done regularly to keep the basins free of weeds when the papaya is planted as a filler in orchards. Two hoeings one in February-March and other in July-August are sufficient to check the growth of weeds. No weedicides should be sprayed since papaya is a shallow rooted fruit crop and plants can be damaged.
Collar-rot or Foot-rot
It is caused by a soil borne fungus Pythium aphanidermatum. In this region, the disease occurs at the base of the stems particularly during the rainy season. The fungus attacks the bark and causes swelling, cracking and rotting of stems and roots, especially in waterlogged conditions or in extremely moist, sticky soils. The terminal leaves drop, wilt, turn yellow and fall.
Control measures: It can be checked by spraying/drenching 6:6:50 Bordeaux mixture or (0.2%) esso fungicide thrice during season. It can be avoided if the plants are on a well drained land.
It is caused by the fungus Rhizoctonia solani and Fusarium sp. in the nursery. In the later stages, this disease is caused by Phytophthora palmivora, mainly in the root system.
Control measures: Application of 100g of lime and 100g of copper sulphate in the pits is an effective preventive measure against this disease. Drenching with formaldehyde two weeks before sowing can give effective control in the nursery.
Damping off (Phytophthora sp)
This fungus kills young seedlings in the nursery stage. This can be prevented by sterilization of the soil of nursery beds with formaldehyde, two weeks before sowing, or treating the seeds with agrosan G.N., captan or Ceresan.
Leaf-curl and mosaic (Papaya ring spot or papaya mosaic virus)
They are observed during rainy season when the vectors are most active and cause considerable damage. In leaf curl, leaves of the plants become crinkled and curled; the plants get stunted with small leaf size and do not grow further.
The mosaic disease starts as necrotic dots on the leaves. The lamina becomes yellowish green, malformed, upright and with blistered patches on it. Fruits are also affected.
Control measures: Practically there is no control measure for these viruses. The virus affected plants should be quickly destroyed to prevent the spread of these diseases. To check the insect vector, plants should be sprayed with 0.05 percent Malathion or metasystox at 10-12 days intervals.
Root knot nematode (Meloidogyne incognita)
Affected plant shows withering, yellowing and wilting. Knot like structures appear on the roots particularly under water logged conditions.
Control measures: This can be checked by use of nematicides (nemagan, nemphas, etc) in the field.
The insect pests of papaya are not that harmful. The most important is the red spider mite, which occurs on the underside of the leaf, which they damage. It can be controlled by spraying fine lime sulphur. Birds cause considerable damage to papaya. Bird-scaring is an important item of expenditure in commercial plantations.
The disease is common in nursery beds. Affected seedlings are topple down on the ground. The disease is more severe in rainy season.
Control: Seed and soil treatment with Trichoderma harzianum formulations @5% and 2% respectively.
The seedlings are affected in the nursery bed.
Control: Drench the soil with 1% Bordeaux mixture.
Water soaked patches are found on the stem which gradually enlarge and girdle the base of the stem. The affected area turns black and rots; later cracks are seen. It is more severe in rainy season.
Control: Spraying of 1% Bordeaux mixture once may check the further spread of the disease.
The fruits are invaded by Phytophthora palmivora causing firm rot, then the injured fruits are attacked by Rhizopus stolonifer and causes soft water rot. Excess soil moisture and soil temperature 20-30O C are favorable condition for diseases development.
Control: i. Spray Bordeaux mixture (1%).ii. Dip the fruits in hot water at 48-50oC for 5 minutes.
The affected leaves shows spots which are grayish-white, circular to irregular in shape. The leaves become yellow and later they die.
Control: Removal of severely affected plants is the only control measure.
Papaya Ringspot virus
Papaya Ringspot virus:
The affected plants are stunted in growth, show yellow mottling and distortion of leaves, bending down of petiole and followed by death of the plant. Diseased plant yields little or no crop.
Control: Bi-weekly spraying with 1.5% mineral oil
Papaya leaf curl:
The virus disease is characterized by severe curling, crinkling, enation and distortion of leaves accompanied by reduction of leaf size.
Control: As the spread of disease is slow roughing of affected plants may give good result.
Papaya Mosaic virus (PMV):
The affected plants becomes stunted, leaves become yellow petiole shows bending downward, occasional shoe-string symptom may also appear. In severe cases plants may fail to flower and plants may die in later stages.
Control: Spraying of proper insecticide will check the insect population and further spread of the disease.
Harvesting and Yield
Usually the fruits are harvested when they are full size, light green with a tinge of yellow at epical end. When the latex ceases to be milky and become watery the fruits are considered suitable for harvesting. First picking may start at 14/15 months after planting. Three to five pickings for one season are often taken fetching about 30-35 tonnes per hectare. Suitable grading must be done before packaging. Since the fruits are highly perishable, care should be taken to wrap the individual in paper and finally packed in crates.