Elsinoë mangiferae

Elsinoë mangiferae produces symptoms superficially similar to anthracnose infections, which are also common on mango. The disease initially presents as small dark brown or gray spots on the underside of leaves or fruit. These spots enlarge and darken over time, developing a velvety or cracked texture in the center of the lesion.[2] The main lifestyle difference between these two is that anthracnose infections are caused by saprotrophic fungi, while E. mangiferae is exclusively a biotrophic pathogen. With severe infections, fruit drop and defoliation may occur, and surviving fruit and plants suffer scarring that reduce their commercial value.

The symptoms of mango scab vary depending on the factors such as the part of the plant that is affected, age of tissue, inoculum potential, water and mineral nutrition. Also, only young tissue is prone to infection. Such as that fruit is no longer prone to infection once it reaches about half size. The appearance of symptoms is dependent on the free water availability when the tissue is at susceptible stages. Few of the symptoms can be mistakenly confused with insect injury or infection from other disease like mango anthracnose.[3][4]

Confirmation of the presence of mango scab requires microscopic examination of material from fruit, stems or leaves, and culture of the organism. Culture will only be successful from lesions on young plant material. This can only be done by a qualified plant pathologist.

Germination of E. mangiferae spores requires a period of moist conditions and free water. The pathogen only infects young tissue, especially newly set fruit. The spores are primarily spread by rain dispersal, over short distances, but heavy rains and irrigation, as well as moisture inclusive microclimate (low ground, etc.) promote conidiation and spread over larger areas.[4]

Control is mainly attempted via regular protective application of copper fungicides, specifically copper hydroxide and copper oxychloride. Increased application schedules are recommended in moist climates and seasons. Benomyl, the systemic benzimidazole fungicide, has also been used as a means to control mango scab infection, but has been out of production since 2001.[2] Reduction of inoculum is also essential for control of this disease. Due to its saprotrophic lifestyle, inoculum can survive on fallen leaves and dead twigs long term, which necessitates the removal or destruction of dead plant material to prevent disease spread. Mango scab is not as common in mango trees because the same fungicide sprayed on the trees for the prevention of the Anthracnose fungus will prevent mango scab from forming.

Elsinoë mangiferae produces brownish ascocarps in the host epidermis. Globular asci are dispersed in ascocarps, and contain 1–8 hyaline ascocarps.

Host tissues are not most susceptible when young, and they usually decrease in susceptibility as they mature. Rainy weather promotes sporulation of the fungus. One common vectors of mango scab is water splashes from nearby Whether or not conidia and ascospores are infectious is not known.[7]