First report of anthracnose of olive fruit caused by Colletotrichum theobromicola in Argentina.
The olive (Olea europaea), family Oleaceae, is an important crop in Argentina, mainly in the production of olive oils and table olives. In the country, the economic loss to the olive industry caused by anthracnose is estimated to be over $9 million dollars a year. During the harvest of 2018 to 2019, severe symptoms of anthracnose were observed with an incidence of 73% on 483 olive tree (cv. Manzanilla) in a commercial orchard located in Capital, La Rioja, Argentina. Lesions on olive fruits were irregular, becoming dark brown and depressed, with mature fruit mummification, being typical lesions of anthracnose. For fungal isolation and identification, conidia were collected from orange masses of spores, in acervuli, from 20 infected fruits of 10 olive trees. Based on the results of morphological observations, molecular investigations (sequence analysis of the partial glyceraldehyde-3-phosphate dehydrogenase, actin and β-tubulin 2 regions) and pathogenicity tests, the causal agent was identified as C. theobromicola. The fungus was previously reported on olive causing anthracnose in Australia. This is thought to be the first occurrence of C. theobromicola in Argentina and the first report causing anthracnose of olive fruit.