Novel Harzia ixtarensis Fungus on Annona cherimola Fruit in Mexico and Its Synergistic Relationship with Colletotrichum fragariae

Since 2005 in Íxtaro, Michoacán, symptoms of infection have been observed on immature fruit with -induced anthracnose lesions and mummified fruit. This study aimed to identify the sp. and evaluate its pathogenicity. Four isolates were obtained from fruit exhibiting symptoms, cultured in four types of agar under various conditions, and characterized based on concatenated internal transcribes spacer (ITS) + large subunit and ITS + small subunit sequences. Additionally, the isolates were compared with two CBS species (two-type strains and two isolates) of and under the same conditions as the isolates, and all known spp. in culture were included in two phylogenetic analyses. sp. nov. was proposed. Compared with CBS isolate 121524 which was the most closely phylogenetically related species, was characterized by slower colony growth (white to salmonish-beige), different percentages of two forms of conidia (elongated and globose; unicellular and hyaline to subhyaline), and smaller conidia. The conidia mainly germinated with two hyaline tubes without an appressorium. In situ inoculations (1 × 10 ml conidia suspension) of fruit showed that fruit with wounds developed larger lesions than those without wounds. inoculation on anthracnose lesions (induced by prior inoculation with ) produced larger anthracnose lesions than alone. When or was inoculated alone, the lesion size was 51 and 99% smaller, respectively, indicating synergy between and . Thus, may have a parasitic-synergistic and necrotrophic lifestyle, and exhibited symptoms on anthracnose lesions.