This proficiency test aims to evaluate the ability of participating laboratories to identify and detect Phyllosticta citricarpa the causal agent of Citrus Black Spot (CBS) from pre-made samples.

This proficiency test is the second test targeting the CBS pathogen and the sixth organized by the EURL for pests on plants – on fungi and oomycetes. Considering that it may be difficult to morphologically distinguish P. citricarpa from other Phyllosticta species occurring on citrus, participating laboratories may combine different approaches. These approaches may include the distinction of morphological features of the colony, sequences of barcoding regions as well as molecular-based methods to determine the identity and the presence of the pathogen in the samples.

Moreover, the EURL will organise an online "informative session" addressed to EU-NRLs where the context of the PT and different aspects will be discusses, as well as the possible methods participants can use for the detection and identification of this pathogen.