Citrosol identifies a new species of Cladosporium that causes losses in citrus

Over and above the commercial activity that is an integral part of all companies, we, at Citrosol, share our knowledge in a tangible way by publishing our researchers’ papers in prestigious scientific journals worldwide. The latest example is a recent study published in the ‘Journal of Plant Science and Phytopathology’, authored by Celia Murciano, Jeniffer J. Oliver-Chirito and Benito Orihuel, on the identification of a new pathogen, Cladosporium ramotenellum, currently the cause of significant losses in mandarins being exported from Peru, adding to food waste in citrus produce.

Until now, only two Cladosporium species have been associated with decay in citrus produce; C. herbarum and C. cladosporoides. We must now add C. ramotenelum to that list which, as an opportunistic pathogen, takes advantage of damage to the rind to infect the fruit via those wounds, or micro-wounds, on the skin.

The pathogen was singled out through molecular identification in both locally grown fruit and fruit from different exports, confirming the presence of Cladosporium ramotenellum, as being the cause of decay in ripe fruit.

The problem is especially serious in the latter part of the season and in quarantine shipments where Cold Treatments are used to control various pests. “The spores of the fungus, carried by the wind, penetrate through weakened areas of the rind. These spores germinate in storage conditions with high humidity”, pointed out Benito Orihuel, one of the authors of this Citrosol paper, “ it is a dry and firm decay process. The attacked areas quickly darken and, on many occasions, a gray or black mycelium develops on them”.

Solutions

This pathology, documented by Citrosol, was, in 2018, the cause of considerable economic damage suffered by mandarin exporters from Peru in their refrigerated shipments to destinations such as Asia or the United States. It has also been noted more recently, although to a lesser extent, in shipments to Europe. To combat the problem, Citrosol makes two recommendations: 1. reduce the inoculum load of Cladosporium sp and C. ramotenellum that the fruit brings in from the field and 2. protect the fruit, the skin, from the Chilling Injury that typically becomes manifest in refrigerated transport, with Citrosol’s Plantseal® or CI-Control coatings.