Production Guide on Papaya

Introduction

Papaya (Carica papaya Linn.), originated from tropical America and is considered as one of most important fruit crops in the Philippines because of its great economic potential. The fruit is cylindrically long, pear shaped or round, it is orange to orange-red, sweet and juicy when ripe. Unripe papaya makes for a good concoction of vegetable stew, salad or pickle. The fruit is rich in Vitamins A and C, iron, calcium, protein, carbohydrates and phosphorous. Papaya produces latex which contains papain – an enzyme that breaks protein. Papain has been commonly of use to the food, pharmaceutical and cosmetic industries. Papain is used for cleansing lotions, facial creams and toothpastes.

A study conducted by the University of Indonesia discovered that glycoside, an organic compound that can be extracted from ripe papaya seeds, reduces fertility among men. This break through is being pursued to provide an alternative contraceptive method for men. Further, a new scientific finding reveals that papaya could be an effective remedy for cancer.

Varieties

‘Solo’ -  ‘Solo’ is an improved, high quality selection with reddish-orange flesh. Its fruit weighs about half a kilogram.

The most popular strains of ‘Solo’ papaya commercially propagated in the Philippines are the ‘Kapoho’ and ‘Sunrise’ which are high -yielding  and pear shaped. They are  smoother and sweeter but smaller and lighter compared to other ‘solo strains.

‘Cavite Special’ - Cavite special is a popular semi-dwarf type that blooms 6-8 months after planting. The fruit is large, oblong and weighs from 3 to 5 kilograms. It has a star-shaped cavity. The flesh is yellow orange and sweet when ripe.

‘Sinta’ -  Sinta is the first Philippine – bred hybrid papaya. It is a cross between Line no. 5 and Line no. 3. It is moderately tolerant to papaya ringspot virus (PRSV) and produces more quality fruits than the ordinary papaya strains. It is semi-dwarf and therefore, easier to harvest.

‘Sinta’ is early maturing and prolific, which bears 17-50 fruits per tree. Its fruit weighs 1.2 – 2.0 kg, is sweet and has firmer flesh.

Red Lady Papaya (F1 Hybrid) - Early, vigorous productive and tolerant to papaya ring spot virus. Plants begin to bear fruits at 80cm. height and normally have over 30 fruits per plant in each fruit setting season. Fruits are short- oblong on female plants and rather long shaped on bisexual plants, weighing about 1.5 – 2 kg.

Known – You No.1 -   Tolerant to papaya ring spot virus. Plants are thick, sturdy early and heavy yielding. Yellow – fleshed fruit is large, weighing about 1.6 – 3 kg.

• Tainung No. 1 - Plants are vigorous and prolific. Fruits weigh about 1.1 kg with red flesh and good aroma.

• Tainung No. 2 - Fruits with pointed blossom end weigh about 1.1 kg. Flesh is orange red, tender with good taste and quality. Suitable for local market.

• Tainung No. 3 - Plants are dwarf but with good growth. Fruits are larger than Tainung No. 1 and weigh about 1.3 kg. Flesh is yellow –orange, sweet and good quality.

Adaptation

Papaya thrives best in areas with dry climate ( 25-30°C ) with annual rainfall of 1,200 mm to 1,500 mm distributed throughout the year. Normally, it is a crop for low to medium elevations (from sea level to 900 meters above sea level) with humid to fairly humid conditions. It requires ample sunshine and protection from strong winds.

Papaya is adapted to a wide range of soils but its grows best in well- drained light textured soils with pH range from 5-6.5.Good drainage is important as water logging kills plants. Sticky and calcareous soil are not good as rain water, may accumulate in the soil even only for a few hours. In this case, raised beds and drainage ditch are recommended.

Cultural Requirements

Land Preparation

Clear the area of all shrubs and trees preferably during dry season and alternately plow and harrow to obtain fine tilth.

Planting

Seeds are recommended to be sown in polyethylene bags. Sow at least 3 to 4 seeds and cover with fine soil. Germination takes 15 to 20 days. Thin out to two seedlings per polybag. A booster dose of 2 grams urea after emergence and 2 weeks interval in subsequent application may be given  for rapid growth and development of seedlings. Regular daily watering is necessary. The seedlings are ready for transplanting when they are about 6 inches high or 2 months old.

Prior to planting , stake at a distance of 2.5 X 2.5 and dig 45 cm X 45 cm holes. Two seedlings should be planted per hole and later thinned out to only one after assurance of  most vigorous tree.

Water Management

Water is required for papaya during the early stages of growth and periods of prolonged drought. Lack of moisture over prolonged periods causes growth retardation, flower abortion and dropping of young fruits.

Water newly transplanted seedlings daily until they become fully established. Young papaya seedlings should be irrigated once a week and bearing trees every week during dry periods. During rainy season, hill up to improve drainage.

Weed Control

Remove the weeds by proper cultivation of the soil around the plants. It is done by hand pulling, hoeing or by shallow cultivation. Extreme care should be exercised in manual weeding around the trees since papaya is shallow-rooted and surface feeder roots injured. Mulch during the dry season to control growth of weeds and to conserve moisture.

Fertilization

The following is the general fertilizer recommendation for papaya:  

Common Pests and Diseases and their Control

Pests

1. Mites - Under local conditions, the red spider mites (Tetranychus kanzawai Kishida) is most common attacking and severely damaging the older leaves of papaya and sometimes attacking its seedlings. Its serious damage causes the leaves to dry up, thus, reducing the photosynthetic activity of the plant.

Control Measures

• To prevent the sources and build up of mite population, leaf pruning and burning of damaged and attacked leaves are done weekly.

• For chemical control, use selective miticides sprayed at 7 to 10 days interval.

2. Scale insects - The most common scale insects species colonizing and feeding on papaya fruit is the Aspidiotus destructor Sig. Their feeding caused the fruit to ripen prematurely and destroy the external appearance of the fruits.

Control Measures

• Spray recommended insecticide to control incidence of scale insects in the fruits. Spraying should be done directly to the fruits 15 days before harvest. Adjust spray nozzle so as not to hit harvestable fruit in case there are available harvestable fruits. Re-spray 7 days after if presence of such pest is still visible.

3. Fruit Fly - Dacus dorsalis and Dacus cucurbitae Coq. are species of fruit fly attacking papaya. When an outbreak in population occurs, the eggs are deposited in the ripening fruits while they are still attached to the tree. Harvested fruits eventually rot as the newly hatched larvae start to feed inside the fruit.

Control Measures

• Sanitation inside the population is essential by gathering all ripened, damaged and fallen fruits. Gathered fruits should be dumped in pit and burned.

• Use Methyl Eugenol to attract male files and kill them.

• Do not allow ripe fruits to remain in the  tree for sometime.

Diseases

1. Damping – off

Symptoms

• Tissues of the papaya seedling stems at the solid line become water-soaked and rotten due to infection by one or more species of fungi-like Pithium debayranum, Pytopthora palmivora and Rhizoctonia sp. It is common in the nursery or in the field where seedlings are too crowded. It is favored by high temperature and wet weather.

Control Measures

• Avoid overcrowding of seedlings.

• Provide good drainage and adequate soil erosion. Practice proper plant spacing and depth of planting.

2. Papaya mosaic

Symptoms

• Leaves of infected plants develop a wrinkled and rough appearance. Younger leaves are generally stunted and chlorotic and are accompanied by vein-banding or transparent oil that are scattered over the leaf veins.

• Older and mature leaves show more pronounced chlorotic areas and are stunted.

• Severe attack results in stunting of petioles.

• Infected young fruit shows small, dark green spots, which appear either on the stem or blossom end. They enlarge as the fruit develops. Mottling of green and brownish rings appear.

Control Measures

• Cut down infected plant and burn.

3. Bacterial Crown Rot

Diseased papaya are really distinguished in the field by the dropping leaves which results from infection of the petiole or stem with the bacterium Erwina cariceae.

Symptoms

• Initial symptoms found on the petiole and stem are water-soaked spots. The spots rapidly enlarged causing rotting of the petiole or stem. Then the crown droops and wilts showing leaf yellowing it may topple-over.

• Young, soft plant parts are susceptible to infection with the bacterium gaining entry through natural openings and wounds. In susceptible cultivars, infection becomes systematic causing vascular discoloration of the stem, fruits and roots. The disease is common during periods of prolonged wetness or continuous rainfall. Infected plants may recover and produce productive branches during dry season.

Control measures

• Eradicate severely infested plants and disinfect tools with 10% formalin solution. In cases when the stem is not infected, remove only the infected petioles and leaves.

• Provide protection to the papaya plants during rainy periods by spraying crown (petioles, leaves, fruit and young stem) with copper fungicide at 3 g/li. of water once every 14 days.

4. Anthracnose

The disease is caused by Collectrichum gleosporiodes and effects not only the fruits but also petioles of older leaves.

Symptoms

• Small, round, water-soaked areas appear on infected ripened portion of the fruits.

• Fungus produces pink spore masses, which appear in concentric rings in the lesions. Fungus also penetrates into the tissues of the fruit, causing it to become darker and softer than the surrounding tissues.

• Infected portion have unpleasant flavor.

• On green parts, it appears as small, water-soaked lesions oozing out from the infected areas.

Control Measures

• Spray with recommended fungicide plus a spreader sticker to ensure good spray coverage at 7-10 days interval.

• Post harvest storage decay can be reduced by treating fruits in hot water at temperature of 110-120°F for 20 minutes.

5. Pythoptora rot

Symptoms

• Seedling damps-off, root rots, trunk cankers and fruit rots.

• Immature fruits are attacked through wounds while mature fruits at any location.

Control Measures

• Remove infected fruit and dispose properly.

• Spray copper fungicide at recommended rate. (For fruits in storage, control by hot water dips at 46.7°F for 20 minutes then cool with running tap water.)

6. Papaya Ringspot Virus

The Papaya Ringspot Virus (PRSV) is readily transmitted mechanically by sap. It is also stylet born and insect transmitted by aphids. It is not readily transmitted through seeds.

Symptoms:

• Vein clearing, mottling and the presence of yellow spots are the initial symptoms of the leaf.

• Later, the leaves are reduced in size and margins tend to curl upward and downward. Dark green concentric rings or green spots appear on fruits and the disease progresses, fruit set is sharply deformed and smaller.

Control Measures:

• Eradication of infested plants and spraying the infected and the apparently healthy tree surrounding it with appropriate insecticide before uprooting and chopping the infected trees to small pieces. Place the chopped plant debris in a sack or plastic bag and burn it in a suitable place.

• Never intercrop papaya trees with possible alternate host such as watermelon, cucumber, squash, etc.

• Enforce quarantine measures prohibiting the transfer and introduction of papaya and alternate hosts from affected orchards to new growing areas.

• Use resistant papaya cultivars.

Harvesting and Post Harvest Management

Papaya generally starts to flower after 5 months from seedling and the first harvest is obtained 4 to 5 months later. When intended for vegetable, papaya can be harvested when fruit is at color break to ¼ ripe. For shipping to distant market the fruits should be harvested when the apical end starts turning yellow and the latex is no longer milky. Do not allow fruits to ripen on the plant and they should not be dropped to the ground to avoid possible injuries. Use step ladder or plumber helper with long bamboo pole to pick the fruits if the tree grows taller.

To harvest, to twist the fruit until its stalk snaps off the plant or cut the stalk with sharp knife.

The productive lifespan of papaya gradually ends on the 3^rd or 4^th year. As the tree matures, production also slackens. The yield of well-managed papaya plantation is 35 to 40 tons per hectare.

Packing

A good  method of packing is to place the fruits in single layer in a rectangular wood container lined with dried banana leaves or shredded newsprint to protect the fruit against the normal hazards of transport and handling.

Storing

Ripe papayas may be stored at 8.3°C  and partially ripe ones at 11.9°C. At these temperatures, the fruit can be kept for 3 weeks. To avoid chilling injury which is manifested by impaired ripening, do not store less mature fruit below 7.1°C.

References

Grow Papaya. Mimeographed Guide. Bureau of Plant Industry, Manila.

Loquias, Virgilio L. Guide to Solo Papaya Production. Bureau of Plant Industry, Davao NCRDC, Bago Oshiro, Davao City.

National Fruit Congress & Exhibition ’95 Souvenir. Sinta Hybrid Papaya. Cagayan De Oro City.

Papaya. Mimeographed Guide. Bureau of Plant Industry, Manila.

Philippine Agribusiness Investment Profile. Papaya. Agribusiness Investment Information Division/Service Department of Agriculture, Diliman, Quezon City.

Sarcos, M.A. Technoguide  in Papaya Culture. Davao NCRDC, Davao City.

Management Practices for a Profitable Papaya Production. Known – You Seed Co. and Harvest  Agribusiness Corp.