Hidden diversity behind the Lecanicillium <i>-</i> like white colony-forming mycoparasites on <i>Hemileia vastatrix</i> (coffee leaf rust)

During surveys for fungal natural enemies of <i>Hemileia vastatrix</i> - the causal agent of coffee leaf rust (CLR) - in its African centre of origin (Cameroon, Ethiopia), as well as in its exotic South American range (Brazil, Paraguay), an eclectic and species-rich mycobiota was encountered. Here, we provide a comprehensive report on an assemblage of "white colony-forming fungi" (WCF), often treated in the earlier literature under the inadequate "label" <i>Verticillium lecanii</i> (=<i>Lecanicillium lecanii</i>). A total of 265 isolates of WCF were provisionally placed in this arbitrary group. We clarified the identity of our assemblage of Lecanicillium-like fungi using a combination of morphological characteristics and sequence data for the large subunit nuclear ribosomal DNA (LSU), translation elongation factor 1-α (<i>TEF</i>) and the largest subunits of RNA polymerase II (<i>RPB1</i> and <i>RPB2</i>) regions. Fifteen WCF species belonging to eight genera across three hypocrealean families (<i>Bionectriaceae</i>, <i>Clavicipitaceae</i> and <i>Cordycipitaceae</i>) were found parasitizing pustules of CLR. Significantly, <i>Lecanicillium lecanii</i> was not found to be present amongst these taxa. Six species belonged to the known genera - <i>Corniculantispora</i>, <i>Gamszarella</i>, <i>Lecanicillium, Ovicillium, Pleurodesmospora</i> and <i>Simplicillium</i>. Two new genera are described, <i>Bettiolomyces</i> and <i>Hemileiophthora</i>, as well as seven new species, <i>Bettiolomyces urediniophagus</i>, <i>Gamszarella uredinophila</i>, <i>Hemileiophthora denticulata, H. nodosa, Lecanicillium hemileiae</i>, <i>Pleurodesmospora hemileiae</i> and <i>Simplicillium hemileiae.</i> The following known WCF species are recorded here for the first time on pustules of <i>H</i>. <i>vastatrix</i>: <i>Corniculantispora dimorpha</i>, <i>Gamszarella buffelskloofina</i>, <i>Lecanicillium uredinophilum</i>, <i>Ovicillium attenuatum</i>, <i>Pleurodesmospora coccorum</i> and <i>Simplicillium subtropicum.</i> Additionally, the new combination <i>Bettiolomyces epiphytus</i> is introduced for <i>Verticillium epiphytum</i>. <b>Citation:</b> Colmán AA, Araújo JPM, Evans HC, Correa Mansur PS, Salcedo-Sarmiento S, Silva AL, Kapeua-Ndacnou M, Belachew-Bekele BK, Pereira CM, Crous PW, Barreto RW (2025). Hidden diversity behind the Lecanicillium-like white colony-forming mycoparasites on <i>Hemileia vastatrix</i> (coffee leaf rust). <i>Persoonia</i> <b>55</b>: 239-275. doi: 10.3114/persoonia.2025.55.07.