Diversity of fungicolous fungi associated with <i>Camarotella</i> spp. ( <i>Phyllachorales</i> , <i>Sordariomycetes</i> ) on <i>Cocos nucifera</i> in Brazil, including <i>Fusicolla parasitica sp. nov.</i> ( <i>Nectriaceae</i> )

<i>Camarotella torrendiella</i> and <i>Camarotella acrocomiae</i>, the causal agents of coconut black leaf spot, are of great economic importance to coconut cultivars. Species of hyperparasites have previously been reported in the stromata of these species, which delay and reduce the viability of the ascospores of these pathogens, demonstrating their bio-control potential. In order to identify and analyse the parasitic species affecting the pathogens that cause coconut black leaf spot, symptomatic leaflets exhibiting parasitized stromata of both <i>C. torrendiella</i> and <i>C. acrocomiae</i> were collected in the states of Pernambuco and Paraíba (Brazil) and the fungi present in the stromata were isolated. The hyperparasites were phylogenetically identified based on different gene regions according to genera and presented in this paper with a detailed taxonomic description as well as their abundance and constancy in the coconut grove. A new species of <i>Fusicolla</i> was described in this study as <i>Fusicolla parasitica sp. nov. Acremonium cavaraeanum</i> presented a new record for the states of Paraíba and Pernambuco. <i>Fusarium pseudocircinatum</i> and <i>Fusarium caatingaense</i> presented the first report of their fungicolous lifestyles, while <i>Purpureocillium lilacinum</i> was for the first time recorded hyperparasitizing a <i>Camarotella</i> spp. causing leaf lesions. This study shows <i>Fusicolla parasitica</i> and <i>Acremonium cavaraeanum</i> as constant and abundant species in the coconut grove, while <i>Fusarium pseudocircinatum</i> and <i>Purpureocillium lilacinum</i> are accessory and common; <i>Fusarium caatingaense</i> was considered rare and accidental. <b>Citation:</b> Sá CEVA, Souza-Motta CM, Tiago PV, Machado AR (2025). Diversity of fungicolous fungi associated with <i>Camarotella</i> spp. (<i>Phyllachorales</i>, <i>Sordariomycetes</i>) on <i>Cocos nucifera</i> in Brazil, including <i>Fusicolla parasitica sp. nov.</i> (<i>Nectriaceae</i>). <i>Fungal Systematics and Evolution</i> <b>16</b>: 155-180. doi: 10.3114/fuse.2025.16.9.