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Viruses
Passion fruit woodiness virus is one of the most well known viruses to the passion fruit. It belongs to the Potyvirus group and can attack a plant at any age from nursery to mature plants. Some features include yellow leaves that display distortion in the leaf length and shape. As well as affecting the leaf, this virus influences fruit shape and size. Affected fruits become stone-like and under-sized, with many fruits becoming scabbed and cracked. The virus is spread through sap sucking insects such as aphids and mites. Woodiness can also spread through vegetation propagation such as infected scions or contaminated tools. There is no chemical control for this virus once the plant is infected but the use of clean planting material can reduce its dissemination.

One of the most serious viruses pertaining to vegetation is the Cucumber mosaic virus. In the passion fruit, this virus appears with yellow mottling on leaves starting at random points on the vine and diminishing in intensity towards the tip. Expanding leaves typically become twisted, curl downward, and develop a "shoestring" appearance as a result of a restriction of the leaf surface. It is mobile and can spread easily through interactions with other plants such as brushing between leaves. This virus is naturally transmitted through aphids and can also be transmitted mechanically through seedlings. Varietal resistance is the primary management tool, and eliminating weeds and infected perennial ornamentals that may harbor the virus is critical. Once the plant has been infected, there is no possible management of control for the virus.

Phytoplasma
Overshooting is the term used when Phytoplasma, a specialized bacterium, attacks the phloem of a plant. Phytoplasma infection is characterized by chlorotic small leaves, shortening of internodes, excessive lateral shoots and abnormal flowers. Although there have been reports of this disease within the passion fruit plant, many infected plants are affected without visible signs of disease. Although Phytoplasma can be spread through grafting, it can be inhibited by periodic inspection of plant nurseries and areas that have had past infections. Overshooting responds to treatment with tetracycline, a common broad-spectrum antibiotic.

Bacteria
Bacterial leaf spot, which causes vein clearing, forms bright yellow colonies, dark green small spots encircled by a chlorotic halo on the leaves, causing infection and leaf wilt and, eventually, deterioration of fruit pulp, especially of young fruits. Under favorable conditions for the bacteria, infection occurs through natural openings or wounds from other pathogens that affect the inter-cellular spaces. Fertilizers or a copper chloride and mancozeb mixture can control the intensity of the disease, but it is not a cure.

The bacterial grease-spot of the passion fruit is similar to the commonly known hard grease spot and is caused by the Pseudomonas syringae. It appears with olive green to brown greasy looking spots or brown sunken circular lesions. On a later stage, a hard crust can cover the lesions showing a chlorotic halo. Affecting the stomata and hydrathodes, the grease-spot favors high temperatures and relative humidity. To avoid infection, measures that should be adopted include planting seeds from healthy plants and into healthy areas. Chemical controls such as supric and carbamate fungicides that contain streptomycin or oxytetracycline can aid in prevention of infection.

Fungi and Fungus like organisms
The collar rot disease is caused from the fungus Fusarium solani. It is characterized with necrotic lesions at the collar region, browning of stem tissue at soil level, and dark discoloration of the stem tissue. Because of the rotten tissue, this interferes with the food and water translocation in the plant which leads to withering, and drying of the plant until death. Infection occurs mostly through contaminated soil and infected plants which cause the plants to survive for only a few weeks. There are no chemical controls. Management includes planting seedlings in unaffected areas and using clean tools.

The fungus Fusarium wilt commonly occurs in adult plants and is caused by the fungus Fusarium oxysporum. The pathogen has ability to survive for long periods. It penetrates the roots and its hyphae invade the xylem vessels, preventing the transport of water and nutrients to other organs of the plant. When infected, this diease displays yellow leaves and browning of the vascular system until it wilts and dies. It occurs in any type of soil infecting all plants. Management of crops include planting clean seedlings, uprooting and burning infected plants and using sterilized tools.

The anthracnose, caused by the colletotrichum gloeosporiodes, is a pathogen of the passion fruit creating dark and sunken lesions. By attacking mature fruits, these lesions spread and cause intense defoliation. The fruits rot becoming oily in appearance. Many leaves die due to the foliar lesions and the skin of fruits become papery. Under warm and humid conditions, this disease can worsen causing red and orange spores eventually killing the plant. Infection is carried out through the residues of the passion flower, infected seeds, seedlings, and cuttings. To manage this disease, use of pathogen free seedlings, elimination of infected areas, improved ventilation and light conditions help control the disease. Copper based fungicides on injured areas will prevent the spread of disease.