Nearly all passion fruit growing areas in Kenya are infested with the woodiness viral disease, USAid-Kaves says. This and other pests and diseases limit the economic lifespan of most passion fruit orchards to a maximum of 24 months. Experience has shown that planting healthy seedlings and maintaining an orchard at least during the first six months after transplanting guarantees better returns even if woodiness appears later.
Use clean planting materials and copper-based fungicide sprays during the cold/rainy season. Field hygiene is recommended. Use of bio-pesticides is encouraged for the requisite Maximum Residue Limit (MRL) incidence. Integrated pest management techniques such as orchard sanitation and physical control using insecticide-treated nets and sleeves, are also encouraged. When transplanting, drench the hole with Trichoderma at a recommended rate of 1 ml/lt of water. There are a number of pests such as insects, and nematodes and diseases that affect passion fruit. Thrips, phytophthora blight, and brown spots are the major pests and diseases of the fruit
Pests feed on the plants, sucking sap from the growing tips or from developing fruits. Bug attack (by both nymphs and adults) is sporadic and coincides with warm weather. Nematodes can cause severe problems in passion fruit, but only in the purple varieties, as the yellow ones are completely resistant.
There are few pesticides registered under PCPB (write out in full) for control of pests and diseases in passion fruit since it is considered a minor crop. This has resulted in the use of unregistered pesticides, posing the risk of noncompliance and market loss.
However, there is a need to expand the area under passion cultivation to meet the increasing demand. The increasing pest pressure provides a prospective business venture for agrochemical companies to invest in
PASSION FRUIT WOODINESS POTYVIRUS (PWV)
This is an important disease of passion fruit that is transmitted by aphids. Its symptoms include distortion of leaves and woodiness of fruits. Plants are stunted, yields are reduced and vines die. It also causes yellow spots, flecks or mottling on leaves.
MANAGEMENT OF WOODINESS VIRUS
There is currently no treatment of woodiness virus. However, a number of cultural practices can help to mitigate the impact of the disease. They are as follows:
- Seedlings: Produce and plant virus-free seedlings;
- Eliminate old and abandoned orchards before the start of production; Seedlings: Produce and plant virus-free seedlings;
- Infected vines: Cut out infected vines and replace them. Pick up and dispose of any fallen fruit from your passion plant or other fruit trees.
- Pruning practices: Pruning tools can spread viruses. Use hand pruning to check spread of virus and when using tools disinfect them with bleach
- Weeds: Keep weed-free to remove hosts of the virus.
- Chemical control is inappropriate. Although there are insecticides to kill aphids, they are not effective in stopping the spread of viruses, because it is so rapid. By the time the insecticide has killed the aphids, they will already have fed on and infected the plants with the virus(es).
- Use of Neem oil: According to a 2015 Brazilian research, The Neem Oil in Passion Fruit Management by Rafael Mattos Deus and Aloísio Costa Sampaio, this has great potential to control the incidence of viruses in passion fruit because it repels the vector insect. There is a lower incidence of the symptoms of the virus in treated plants
BROWN SPOT (ALTERNARIA PASSIFLORA)
This is the most important disease of passion fruit favored by warm and moist weather. It attacks leaves and fruits, causing brown rings with dead spots. On leaves, small brown spots appear first. These enlarge, develop a lighter-colored central area, and become irregular or angular in shape. Apply Bacillus subtillis to control brown spots at vegetative stages and at 1ml/lt of water.
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. Leaves have tiny superficial, irregular, light-brown spots that appear quickly followed by severe defoliation.
FUSARIUM WILT (FUSARIUM OXYSPORIUM)
Now very serious in Kenya. Causes wilting and death of plant. The vascular tissues show brown discoloration.
Appears as dark water-soaked lesions on leaves. These later spread as infected tissues die. Young shoots also can be infected.
It starts at the tip of branches or in the middle. In its terminal phases, branches die back and cortical dries up.
- Broad mite or yellow tea mite –one the most important mite pests of passion fruit in Kenya;
- Mealy Bugs (serious in the warm season);
- Fruit Flies,
- Leaf Miner,
- Fruit Suckers – mainly stinkbugs
- Apply Metarrhizium strain 69 to control thrips and sting bugs. Thrips management is critical to avoid flower abortion.