Colletotrichum acutatum and Colletotrichum nymphaeae causing blossom blight and fruit anthracnose on olives in southern Brazil

Olive (O. europaea L.) is an expanding crop in the south of Brazil. Blossom blight and typical anthracnose symptoms on fruit were observed in olive trees in an orchard in Rio Grande do Sul, Brazil. Fungi were isolated from symptomatic flowers. Fungal isolates were confirmed as pathogenic after Koch's postulates were fulfilled. Blossom blight and typical anthracnose symptoms with salmon conidial masses were observed in flowers of cultivars Arbosana and Arbequina, at 96 h after inoculation (hai), and on fruits of cultivar Arbosana, at 120 hai. The identification of the pathogens was carried out using a polyphasic analysis approach, combining morphological and molecular characters of specific genomic regions (ITS, GAPDH, ACT, HIS3, and TUB2). Morphological characters and phylogenetic analyses revealed the isolates as Colletotrichum acutatum and Colletotrichum nymphaeae. Until now, the species C. nymphaeae had not been identified as causing anthracnose in olive trees in Brazil.

Automated summary

The study found that the cultivars Arbosana and Arbequina of olive trees in a fruit orchard in southern Brazil exhibited blossom blight and typical anthracnose symptoms caused by Colletotrichum acutatum and Colletotrichum nymphaeae. This is the first report of C. nymphaeae causing anthracnose in olive trees in Brazil.