Alternata Spot in Passionfruit

Alternata Spot in passionfruit is caused by the pathogen Alternaria alternata. This disease is very similar to brown spot but is caused by a different species of Alternaria. The symptoms and infection biology of these two species are very similar. Alternata spot is less common than brown spot.

Symptoms include circular spots on fruit that are smaller than those of brown spot. They are at first very small, with a brown centre and a green, greasy margin. At later stages, the spots become sunken and lighter brown in colour with a diameter of approximately 1 cm. On leaves, spots are generally up to 5 mm in diameter and often surrounded by a yellow halo. Spots can coalesce and form large lesions. Similarly to brown spot, infected leaves drop while infected fruit remain attached to the vine. Stems also become infected, usually next to leaf petioles, resulting in lesions.