PASSION FRUITS (Passiflora edulis)

Passion fruit is in the family Passifloraceae. It is a vigorous vine which flowers and produces fruits within a year. The vine is shallow rooted woody climber. The fruits are oval shaped or round with rough waxy rind. The rind hue ranges from dark–purple with faint fine white specks to light yellow. The fruits contain a flavourful juice that is sub-acid to acid. Fresh passion fruit is high in beta carotene, vitamin C, potassium and dietary fibre.

Figure 9: Purple passionate & Yellow passion

Purple passion                                                          Yellow passion

Varieties

Varieties Description Remarks
Purple passion fruit

(Passiflora edulis)

It is the most important in fruit juice industry.

The fruit is round or oval, and changes its colour from green to purple when ripe.

The flavor is outstanding in fresh, canned or frozen

It grows well in cool temperatures at altitude 1200-1800m asl.
Yellow passion (passiflora edulis var flavicarpa) The average fruit is slightly larger than the purple and turns from green to yellow at maturity. The pulp is very aromatic but rather acidic. It is more vigorous and better adopted to tropical lowlands than purple passion fruit.

The variety is mainly used as rootstock for grafting purple variety due to its resistance to soil borne pathogens.

Sweet passion (Passiflora ligularis) The fruit is of excellent flavor and turns from blue to orange-brown at the time of ripening.

The whitish aromatic pulp is enclosed in a hard shell, which can stand transportation without damage.

It thrives best in cool conditions for optimum growth and altitude above 1500m asl.
Banana passion (Passiflora quadrangularis) The plant has very attractive pink, pendulous flowers which develop into quite edible, yellow, elongated fruit when ripe. Grows in cold conditions and altitude of above 1500m a.s.l
Giant passion fruit(Passiflora mollissima) Pulp and flesh are eaten and fruits appearance resembles a vegetable marrow.

It grows to a length of 30m and fruits turn yellow when mature.

It requires a tropical climate and grows best from 0-1700m asl.

 

Ecological Requirements

Altitude

The most suitable altitude for passion fruit production is 0-1800m asl.  The purple passion is sub-tropical whereas the yellow passion is tropical.

 

Rainfall

A well distributed rainfall of 900-2000mm per year is suitable but supplementary irrigation is recommended if rainfall is low. Excess rainfall causes poor fruit set and encourages diseases.

Soils

It grows on a wide variety of deep fertile soils. Light to heavy sandy loams of medium texture with good drainage are most suitable. A soil pH of 6.0-6.5 is best. In high rainfall areas, the soils should be well drained as plants will not withstand water logging or flooding for any considerable period.

Temperature

Optimum temperatures for purple and yellow passion are between 18-300C and 25-300C respectively.

Propagation

Passion fruits are usually raised from seed taken from healthy plants. P.edulis is susceptible to a number of pests and diseases, grafting is recommended using the yellow passion variety as root stock.

 

Raising seedlings

  1. Extract seeds from healthy fresh fruits selected from healthy and high yield plants. Pick fruits from the vine and avoid fruits fallen on the ground. Seeds should not be stored for more than 3 months after extraction.
  2. After extraction, seeds can be treated with hot water at 500C for 15 to 30 minutes to reduce disease incidences.
  3. Soak seeds for 24 hours to stimulate germination.
  4. Sow seeds in seedbeds or in a container, 7 seeds per container, in a protected and shaded area.
  5. The seeds germinate in 2-3 weeks
  6. Select and remove the weak plants
  7. Soon after germination, the seedlings should be staked and trained up the stake. This is to help the young plant avoid contact with the soil, which is usually the source of fungal diseases.
  8. Transplant seedlings when they are 20-30 cm high.

Raising rootstocks for grafting

Yellow passion is recommended for rootstock. Usually seedlings take 3-4 months from sowing to planting. Grafting is recommended 3-4 weeks later when seedlings are 30-40cm high.

  1. Select the scions from purple passion fruit mother plants that are healthy and high yielding.
  2. Cleft grafting is the common method used in passion fruit but whip or side-wedge methods can also be used.
  3. Cut off 10cm of rootstock that has attained a height 30-40 cm.
  4. Grow the grafted plants under shade for 3 weeks before transplanting them in the field.
  5. Remove all growing shoots from the root stock below graft union

 

Land preparation

Passion fruit has a deep root system therefore deep ploughing and harrowing is necessary to open up the soil for aeration and good water infiltration. Land preparation should be done 2-3 months before planting and hard pan within 80cm zone broken. Dig planting holes 60cm x 60cm x 60cm at least 3 weeks before transplanting spaced at 2 x 3m. Separate the top soil (the first 30cm) from the sub-soil.

 

Manure and Fertilizer

Passion fruit responds well to manure. Add 175g of TSP or DAP and 20kg of farmyard manure to each hole and mix well. Note; the type of fertilizer to use is determined by soil pH.

Transplanting

Transplanting of grafted seedlings is done at the beginning of the rainy season preferably early in the morning or late in the afternoon unless irrigation is available. Ensure that the roots are not folded and prune long roots back. In drier areas watering and mulching of young plants is required immediately after transplanting.

Trellising/Training

A trellis is needed to support the vines. These should be made before planting the seedlings or before the plants start climbing. Wooden posts of 2.7m high and 15cm diameter are used.

  1. Place the posts in holes 50cm deep and 6m apart in a row. Lay posts across each planting row.
  2. Anchor the end posts firmly. An 8-10 gauge galvanized wire is fixed tightly to the top of each post in the row. Use strong enough support to carry the weight of the plants.

 

 

Training

Train 2 healthy shoots up sisal strings by twinning them regularly, until they reach the wire at the top. Remove all shoots below the wire regularly.

After the trained shoots have reached the wire, carefully wound the two trained shoots around the wire in opposite direction. While shoots are growing along the wire, the secondary laterals shoots, which bear fruit, are left to hang down.

When main shoots reach the wire they are trained along it.

 

Any lateral trailing on the ground should be cut off 15cm from the ground.

After fruiting each lateral should be cut back to a new lateral. If none have developed cut the old lateral back to the third or fifth node from main leader


Pruning

Old unproductive shoots and dead wood should be removed regularly. Also secondary shoots reaching the ground level have to be cut off about 5cm above the ground. The laterals which bear fruit should be left to hang down freely from the wire and the entangling tendrils removed to allow free air, light penetration and reduce incidences of disease and pest epidemics. Disinfect all equipment used for pruning to control spread of viral diseases.

Intercropping

During orchard establishment, intercropping with short-term annuals is possible. Suitable vegetable crops such as kale, cabbage are recommended but not beans as they harbor nematodes. Intercropping also prevents soil erosion but the application rates of fertilizer have to be increased.

Weeding

Weeding should be done regularly. Care should be taken when weeding in order to avoid any injury of the plant.

 Manure and Fertilizers

  • Apply manure at planting and add 20-40kg every year before the rains begin. The manure should be well incorporated into the soil.
  • Apply 250-300g of CAN per plant per year distributed in two applications of 125-150g at the beginning of each rainy season. First application should be applied 2 weeks after transplanting. Spraying with foliar and trace elements every 3 months is also recommended.

Irrigation
Irrigation is needed in areas where the annual rainfall is below 1200 mm. Regular watering will keep vines flowering and fruiting continuously.

Rotation

To avoid build up of soil borne diseases strict crop rotation should be practiced. Passion fruits should not be grown for more than 5years on the same plot.

Pests

Pests Description and Damage Control
Aphids

(Aphis Gossypii and Myzus persicae)

They are green in colour and suck plant sap from tissues. Severe attack leads to stunted growth when tips of the shoot are covered with aphids. Aphids may be vectors of woodiness virus and other viruses. Preserve natural enemies e.g. parasitic wasps, ladybird beetles and lacewings by using selective pesticides e.g. pesthrin

Remove weeds from the vicinity of the crop.

Mealy bugs (Planococcus citri and P. kenya) They are small soft bodied, oval shaped insects covered with a white mealy secretion. They sack sap from all parts of the plant causing discoloration, dieback, leaf/fruit fall and retarded growth.

They produce honey dew which attracts ants accompanied by sooty mould fungus.

The entire plant withers and dies. The roots may occasionally be attacked leading to death of the plant.

Natural enemies’ particularly parasitic wasp, lady bird and lacewings normally control mealy bugs.

Keep ants away from mealy bugs since they disturb the natural enemies.

Application of a suitable insecticide e.g. Desis, Bulldock Star immediately after pruning should clean up the vines before the new canopy grows and offers protection to the pest.

In case of root infestation, drench with insecticide

Leaf miner (Lyriomyza spp) Leaf miner adults are small flies black and yellow in colour.

They mine leaves through feeding and lay eggs in them.

Flies cause spotting of leaves. This can kill seedlings and in older plants allows entry of disease-causing micro organisms. Feeding by maggots causes mining (tunneling) of leaves reducing the productive leaf area. Heavily attacked leaves may drop off, and may lead to yield losses.

Control by natural enemies is important.

Ploughing can help in exposing pupae to desiccation and natural enemies

Neem products e.g. Achook EC. Neemros are effective for controlling leaf miners

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Bugs

Green stinkbug (Nezara viridula)

Brown stinkbug (Boerias maculata)

Coreid bugs e.g. giant coreid bug or tip wilter (Anoplocnemis curvipes)

Leaf footed plant bug (Leptoglossus membranaceus).

Bugs suck sap from the growing tips or developing fruits.

The bugs pierce the terminal buds, which eventually wilt and die back. Young plants may be killed if the attack is severe. The punctured young fruits develop localized hardened spots that remain on the fruit reducing their market value.

·         In small orchard bugs can be handpicked and destroyed.

·         Watering and irrigation discourage bugs.

·         Old crops or sprouting stumps left in the field provide refuge for bugs so they should be destroyed or dug into the soil.

·         Growing strong smelling plants such as garlic and onion near the crop is reported to reduce infestations.

·         Use of insecticides e.g. Decis,Confidor 200SL when necessary.

Broad mite or yellow tea mite (Polyphagotarsonemus latus) It is the most important mite pest of passion fruit in Kenya.

Broad mites are tiny (0.1-0.2 mm long), cannot be seen with the naked eye and are even difficult to detect with a hand lens.
Their feeding produces discoloration, necrosis of tissues and deformation.

Initial attack occurs on stems of terminal shoots and young terminal leaves.

Attacked young leaves are stunted, deformed (slender, twisted or crumpled), fail to elongate and finally may wilt and dry.

Stems of terminal shoots may become slightly swollen, roughened or russeted.

As a result the growth of the plant is affected and flower production reduced causing considerable yield reduction.

A bronzed dusty appearance may occur on affected plant parts. Attacked fruits become deformed and show white to tan or brown scars on the skin.

This damage usually does not affect the internal quality of fruits but affect their market value. Severely attacked fruits may fall. Symptoms remain for a long period of time after control.

 Use chemicals such as Omite, Kelthane, Mitac or Brigade where infestation is heavy
Flower thrips

 

Adults are small, slender and usually winged. Their wings are long, narrow and fringed with long hairs and at rest, are tied dorsally along the body. Thrips feed by piercing and sucking sap from leaves flowers and young fruits, causing deformation and scarring fruit.

Flower abortion may occur  as a result of heavy infestation

Use glue coated boards to trap adult thrips. A coat of clean engine oil can be used instead of glue

 

Diseases

Disease Symptoms Control
Brown spot (Alternaria passiflorae) This is a serious fungal disease; affects leaves, stems, and fruit. On leaves, small brown spots appear first. These enlarge, develop a lighter-coloured central area, and become irregular or angular in shape.

On stems, elongated dark-brown lesions appear, usually near leaf axils or where stems have rubbed against the supporting wire. Infection spreads from these points and whenever the stem becomes completely girdled the shoot suddenly wilts and fruits collapse.

On fruit, spots first appear as pinpricks, which enlarge into sunken circular lesions with brownish centres.

Eventually the rind round the diseased area becomes wrinkled and the fruits shrivel and drop.

·       Yellow passion fruit and its hybrids are more tolerant of this disease.

·       Field sanitation (collection and disposal of fallen diseased fruits, leaves and vines)

·      Pruning vines to reduce density and thereby reducing humidity within the crop. It also facilitates better air circulation, light and spray penetration and cover.

·         Timely sprays with copper based fungicides. During humid weather, when the vines are growing rapidly, reduce the intervals between spray applications to 2 or 3 weeks to ensure that new growth is adequately protected.

Woodiness (Cucumber mosaic virus) Woodiness may be caused by the cucumber mosaic virus or by the passion fruit woodiness virus (a member of the potato virus group), or by both viruses in combination, and possibly even other viruses as well.

On leaves it causes yellow spots, flecks, or mottling, and in foliage there is crinkling or distortion. It also shows as shortened internodes on the stems, bunching of foliage, and stunted growth.

On fruit it causes thick, hard, distorted woody rinds, often with characteristic scabs and cracks. Pulp yields are much reduced.

When vines are under any sort of stress (e.g. lack of water, lack of nutrients), the disease becomes evident and slows growth.

Plant only virus-free plants and remove and replace severely infected vines.

Once vines become infected there is no known control.

Aphids that cause cucumber mosaic virus should be controlled carefully. Cucurbits should not be grown near passion.

The effects are minimized, however, by promoting vigorous vine growth.

Fusarium wilt (collar rot)

Fusarium oxysporum f. sp. Passiflorae

This is most likely if resistant rootstocks were not used. The leaves turn yellow and drop off. The collar region of the plant at the soil level turns brownish and vertically cracks.

It normally causes rapid wilting of the entire plant within one or two days especially in very hot weather

Use resistant varieties e.g. yellow passion fruit which as rootstock and graft to purple passion

Do not grow passion fruit where the disease has previously occurred

Use disease free seeds.

Remove and destroy all infected crop residue from the field.

Septoria  spot

Septoria passiflorae

Note the fruiting bodies containing fungal spores seen as minute black dots within the spots

On leaves, tiny, superficial, irregular, brown to black spots appear quickly followed by severe defoliation as infection spreads. Spots on stem are similar but elongated.

On fruit, the infection initially appears as small spots, similar to those on the leaves and stems.  The spots develop into extensive superficial lesions causing premature drop and fruit decay.

Practice field sanitation

Prune to remove all dead and weak diseased parts.

Use copper based fungicide in serious infections

Phytophthora blight (Phytophthora nicotianae var. parastica)

(Phytophthora cinnamon)

Affected leaves are water-soaked and light-brown in colour. They fall readily leading to defoliation of the vines.

Affected areas of the stem are first purple and later brown above the graft union.

They may completely girdle the stem causing wilting and collapse of the vine.

Fruit symptoms comprise of large water-soaked areas.

Diseased fruits fall readily and in wet weather become covered with white fungal growth.

Another strain of the fungus causes root rot. Yellow and purple varieties have different patterns of susceptibility.

The yellow vine is susceptible to P. cinnamoni, and the purple vine is more susceptible to P. nicotianae.

Both fungus strains attack both passion fruits and can cause root rot, wilt, damping off and leaf blight.

Fungal spores are initially produced in wet soil beneath the vines and are splashed up to lower leaf canopy.

The disease is favored by wet, windy weather.

·         Field sanitation

·         Pruning and keeping a grass sward under the vines to minimize spore splashed up to the lower leaves

·         Use resistant varieties (e.g. P. caerula)

·         Use protective copper-based fungicide every 2-3 months during the wet season to reduce disease incidence in areas where the disease is prevalent

    

Harvesting

Harvesting of purple passion fruits starts after 8-12 months after transplanting. For the fresh market, fruits should be picked carefully when they change colour from green to purple, and when the calyx has dried up, leaving a short stalk attached. Ripe fruits fall to the ground and should be collected every second day, stored in a cool place until they are ready for marketing. The yellow passion, P. flavicarpa should be picked when it is yellow.

For processing, the fruits should preferably be allowed to drop onto clean mulch. They should not be plucked from the plant.

For export market they should be picked when they have developed their characteristic fruit colour, purple with some green colour on. For the variety Passiflora edulis flavicarp fruits should be picked when it is yellow in colour

Yields

The average yields are about 10tons per hectare per year. In plantations with good crop husbandry, yields of more than 30-50tons per hectare can be realized.

 

 

Economic lifespan

The economic lifespan of a passion fruit vine is about 3-5 years. After this, disease and insect pest problems often reach a level which makes it difficult to produce good quality fruit.

Postharvest management

The stalk is trimmed to prevent damage to other fruits once packed, and the calyx is removed to improve the appearance of the fruit and help prevent rot. Store the fruits in plastic bags put into crates in order to prevent the fruit from dehydrating and to minimize damage during storage and transport. The fruits can be stored at room temperature for up to one week or refrigerated for up to 2 weeks.

Utilization

The fruits are eaten fresh or processed into juices. The juice is also used in the production of cordials, alcoholic beverages, ice creams, and confectionery and mixed fruit blends.

Marketing

The fruits are sold as fresh fruits in local and export markets or to processors. The major markets for fresh fruits are the urban areas.