Role of fungicides to control blossom blight and fruit rot the main symptoms of olive anthracnose in Uruguay

Olive anthracnose caused by <i>Colletotrichum</i> is the most destructive olive disease worldwide causing blossom blight and fruit root. The <i>in vitro</i> effect of 14 fungicides from six chemical groups on the mycelial growth inhibition of <i>Colletotrichum acutatum</i> s.s., <i>Colletotrichum nymphaeae</i>, and <i>Colletotrichum fioriniae</i> isolates were evaluated. Tebuconazole, pyraclostrobin, and ziram significantly inhibit the mycelial growth of <i>Colletotrichum</i> spp. The effectiveness of these three fungicides was evaluated on detached flowers and copper oxychloride, cuprous oxide, and copper calcium sulfate on detached fruits. Arbequina, Frantoio, Coratina, and Picual cultivars inoculated with these <i>Colletotrichum</i> species were used. Over the flowers, fungicides caused a delay in the appearance of blossom blight between 24 and 48 h and a reduction in the disease incidence by more than 60%. Over the fruits, copper-based fungicides in general failed to reduce the anthracnose severity. This study presents the potential of some fungicides to be used for olive anthracnose control in an integrated management strategy.