First report of Colletotrichum karstii and C. fructicola causing anthracnose in Annona muricata L. (soursop) in Bahia state – Brazil

In June 2022, anthracnose was detected on the leaves of Annona muricata L. (soursop) in Ibirapitanga, Bahia, Brazil. To identify the pathogens, diseased leaves were surface sterilized and cultured on potato dextrose agar, resulting in the selection of two isolates, IBIRA-P5R2 and IBIRA-P2F1R2, which were used for further analysis. IBIRA-P5R2 exhibited gray to white mycelium with dark conidiomata, cylindrical conidia, and dark appressoria. In contrast, IBIRA-P2F1R2 exhibited dense, pale gray mycelium with distinct conidial and ascospore characteristics. Genetic analysis involved sequencing three regions: Internal Transcribed Spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and actin (ACT), with results deposited in GenBank. BLAST analysis revealed that IBIRA-P5R2’s sequences were 95.45% similar to Colletotrichum karstii, while IBIRA-P2F1R2’s sequences were 99.06% identical to . Colletotrichum fructicolaPathogenicity tests confirmed that both isolates caused anthracnose symptoms in soursop seedlings, with dark spots developing on leaves after three days. The pathogens were reisolated from infected leaves, confirming the same cultural and morphological traits as the original isolates. This study marks the firstrecorded occurrence of C. karstii and C. fructicola causing anthracnose on soursop in Bahia, Brazil. The findings aim to inform soursop farmers about this emerging disease, highlighting the need for tailored integrated management strategies to address different plant pathogens effectively.