PASSION FRUITS

Mature Purple fruit Passion

Passion fruits that are mainly grown in Kenya are the purple passion, the yellow passion, giant passion, banana passion and sweet passion. The most common is the purple passion going by scientific name passifloraedullis.


DISEASES

There are several diseases that affect passion fruits categorized into bacteria diseases, pytoplasma, fungus diseases etc.
To view some diseases that can affect you passion fruits, symptoms and control continue scrolling down.

Ripe Purple passion

Matured yellow passion fruit

VARIETIES
Below are different passion fruits grown in Kenya and their requirement to grow.

  • SWEET PASSION (Passiflora ligularis)
  • Regarded as the best tasting passion fruit in the world. The hard-shelled orange-yellow fruit is of excellent quality and has a white aromatic pulp. The vine is easily recognized by its heart shaped leaves. The fruit is between 6.5 and 8 cm long and between 5.1 and 7 cm in diameter. The vines grow on many soil types but light to heavy sandy loams with a pH of 6.5 to 7.5 are the most suitable. Excellent drainage is absolutely necessary. Also, the soil should be rich in organic matter and low in salts. If the soil is too acid, lime must be applied. Because the vines are shallow-rooted, they will benefit from a thick layer of organic mulch.
    Picture

    Sweet Passion seedlings at GTA Nurseries

  • YELLOW PASSION (Passiflora flavicarp
    The yellow passion fruit has somewhat less ascorbic acid than the purple but is richer in total acid (mainly citric) and in carotene     content. It is an excellent source of niacin and a good source of riboflavin. The yellow passion fruit is tropical or near-tropical. It is grown from near sea-level up to an elevation of 2,000 ft (600 m).
  • PURPLE PASSION (Passsiflora edulis)
    Its  one of the most common passion fruit grown by farmers in Kenya,  The purple passion fruit is subtropical. It grows and produces well between altitudes of 1,900 to 2,000ft. The fruit is a vigorous, climbing vine that clings by tendrils to almost any support. It can grow 15 to 20 ft. per year once established and must have strong support. It is generally short-lived (5 to 7 years).

         A well-distributed rainfall of 1000 mm to 2,000 mm per year is suitable for passion fruit production. Excess rainfall causes poor fruit set and encourages diseases.

Fertilization:
Passion fruit vines are vigorous growers and require regular fertilizing. A good choice is 10-5-20 NPK applied at the rate of 3 pounds per plant 4 times a year. Too much nitrogen results in vigorous foliage growth at the expense of flowering. Passion fruit vines should always be watched for deficiencies, particularly in potassium and calcium, and of less importance, magnesium. 
Spraying with foliar feed and trace elements every three months is also recommendedPlants that have been damaged by frost should receive a generous fertilizing after the weather has warmed.

Planting:
It is highly recommended to grow purple Passion Fruit grafted on Yellow Passion rootstocks. Propagation is by seed, stem cutting, or grafted propagules. Planting holes of 45 cm × 45 cm × 45 cm should be dug well before planting.

Transplanting of grafted plants 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 flooded and prune long roots back. In the drier areas watering, mulching, and in some cases, shading of young plants is required immediately after transplanting.

Pruning:
Pruning is necessary to keep the vines within bounds, to make harvest easier and to keep the plants productive by maintaining vigorous growth. In warm winter climates prune immediately after harvest. In areas with cool winters prune in early spring. As a a general rule remove all weak growth and cut back vigorous growth by at least one third. In very hot climates allow a thick canopy of foliage to grow around the fruit to prevent sunburn. 

Almost ripe yellow passion fruit

Propagation:
Passion fruit vines are usually grown from seeds. With the yellow form seedling variation provides cross-pollination and helps overcome the problem of self-sterility. Seed planted soon after removal from the fruit will germinate in 10 to 20 days. Cleaned and stored seeds have a lower and slower rate of germination. Seeds should be planted 1/2 to 1 inch deep in beds, and seedlings may be transplanted when 10 inches high. If taller (up to 3 feet), the tops should be cut back and the plants heavily watered. 

Soil:
Passion fruit vines are grown on many soil types but light to heavy sandy loams, of medium texture are most suitable, and pH should be from 6.5 to 7.5. If the soil is too acid, lime must be applied. Good drainage is essential to minimize the incidence of collar rot.

Spacing:
The recommended spacing is 2 m between rows and 3 m within rows.


Diseases that affect passion fruits and control
Below are a number of diseases that affect passion fruits 

  • GREASE SPOT

This is caused by the bacterium Pseudomonas passiflorae and is one of the most serious diseases of passionfruit, It infects leaves, stems and fruit, leading to severe crop losses and even death of vines.

Symptoms On leaves

it causes irregular olive-green to brown lesions, often surrounded by a light-yellow halo. If unchecked severe defoliation can result. On the stems of young growth the first signs of infection are small slightly sunken, dark-green, water-soaked spots. These develop into light-brown, markedly depressed areas.

Symptoms On older wood
symptoms range from small, slightly sunken, smooth, dark-green circular spots, to large, dark-brown, cracked lesions, which may completely girdle shoots and kill vines. Early signs of infection on the fruit are small, dark-green, oily spots. These develop into roughly circular, greasy, or water-soaked patches. Premature fruit drop and fruit decay result.  However, a condition known as hard grease spot, also caused by Pseudomonas passiflorae, has become prevalent on passionfruit.The symptoms are similar to ordinary grease spot except that the fruit infections dry out and cause a hard brown patch on the skin, instead of leading to decay. This results in a downgrading of fruit and loss of income.

Control
Fertilizers or a copper chloride and mancozeb mixture can control the intensity of the disease, but are not a cure.
To avoid infection, measures that may be adopted include planting seeds from healthy plants and using existing healthy areas. Fungicide controls can aid in preventing further infection.

  • BACTERIAL BLAST BLAST

Bacterial blast blast is caused by a bacterium, Pseudomnas syringae, which is a relative of the grease spot pathogen.

Symptoms and Control
The symptoms of the two diseases are similar, and control measures are the same. Where good control of grease spot is obtained, blast should not be a problem.

  • BROWN SPOT

This is a serious fungous disease, caused by Alternaria passiflorae, which affects leaves, stems and fruit. It occurs mainly in spring and early summer.

Symptoms 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 suddently 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.

Control
Managing this disease involves a combination of using pathogen-free seedlings, eliminating infected areas, and improving ventilation and light conditions. Copper-based fungicides on injured areas can prevent the spread of disease

  • SEPTORIA BLOTCH

Caused by the fungus Septoria passiflorae, this disease attacks leaves, stems and fruit. Even a light infection results in defoliation and premature fall and loss of fruit.

Symptoms On leaves
Tiny superficial, irregular, light-brown spots appear, quickly followed by severe defoliation as infection spreads.

On stems
Spots similar to those on leaves appear. They become deeply sunken but remain minute.

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

Control
Managing this disease involves a combination of using pathogen-free seedlings, eliminating infected areas, and improving ventilation and light conditions. Copper-based fungicides on injured areas can prevent the spread of disease

  • BITTER ROT

The fungus Glomerella cingulata causes this disease and can be responsible for significant fruit loss, especially in hot and humid conditions. Infection is facilitated by any damage to the skin of the fruit.

Symptoms 
Dark, soft lesions rapidly develop on infected fruit that can colonise whole fruit. Infected fruit will fall to the ground.

Control
The routine protective fungicide programme based on copper sprays will afford protection but under stringent infection conditions may need to be repeated at short intervals in the height of very sunny day

Picking up and removing infected fruit is a good hygienic practice.

  • SCLEROTINIA

Sclerotinia sclerotiorum is the causal pathogen of this disease.

Symptoms
It can affect stems where lesions can enlarge to cause a girdling and collapse of the shoots above the lesion. The hard dark sclerotes which are a means of carrying the fungus over from one season to the next can often be seen in infected shoots.

It can also infect fruit with infections rapidly becoming pale brown lesions that can develop over a whole fruit. With advanced infections a mass of fluffy white fungal growth is produced in which the black sclerotes can be seen. Infected fruit falls to the ground, and the sclerotes will carry the infection potential over to future seasons.

Control 
Where Sclerotinia has been a problem application of a suitable fungicide after pruning when the main structure of the plant can be covered is worthwhile.

Orchard hygiene is also important. Infected fruit should be picked up and removed from the orchard, and infected shoots cut out below the lesion and destroyed. This will ensure that the sclerotes are removed and minimise the carryover of infection within the orchard.

  • CROWN CANKER

This is a lethal condition of passionfruit, causing sudden wilting, leaf and fruit drop and death. It has been a major factor in limiting the commercial production of passionfruit

A number of Fusarium species have been isolated from plants suffering from crown canker, the most prevalent of which is Fusarium redolens. Other fungi known to be involved include Fusariumavenaceum, Gibberella baccata, and Gibberella saubinetii.

Symptoms
The condition usually occurs close to ground level, centred on wounds caused by frost, growth cracks, mechanical damage, fertilizer or herbicide burn, or by pest injury such as that caused by slugs or snails. Infections often progress to girdle the stem at or near ground level.

Control
It is  good practice to keep the base of the plant clear of grass and weeds, which favour fungal growth and harbour slugs and snails. Where collars are placed around stems to protect against herbicide damage, slug pellets placed inside the collar will help control these pests.

Plants suffering from crown canker should be carefully removed and destroyed by burning.

  • THIELAVIOPSIS


Thielaviopsis Root Rot This is another fungous disease which can affect passionfruit growing on heavy soils. It is caused by Thielaviopsis basicola.

Symptoms 
Infected plants are unthrifty, with poor-coloured foliage. The roots show signs of decay and are often blackened.

Control 
With mild infections sometimes a severe pruning to balance the top growth with the loss of roots can keep the plants going, but severely infected plants should be removed and replaced.

  • WOODINESSWoodiness may be caused by the cucumber mosaic virus, the passionfruit woodiness virus (a member of the potato virus Y group) or alfalfa mosaic virus, or a combination of these or possibly other viruses as well.


Symptoms
On leaves it causes yellow spots, flecks or mottling, and there is crinkling or distortion. It also shows as shortened inter nodes 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.

Control
Plant only virus-free plants and remove and replace severely infected vines. The disease is transmitted by aphids and possibly also by pruning tools. Once vines become infected there is no known control. Obviously infected plants should be rogued out and destroyed. Virus symptoms are minimised by promoting vigorous vine growth and where necessary aphids should be rigorously controlled.

In older blocks or where some vines may be infected, disinfecting pruning tools between vines or parts of a block could be worthwhile. This can be achieved by dipping pruning tools in a 1% solution of hypochlorite (bleach) for a few seconds, neutralise by a dip in vinegar.

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