Diversity, characterization and fungicidal management of Pestalotiopsis and Neopestalotiopsis species complex associated with raised fruit spots and anthracnose-like symptoms in avocado, India

Avocado (Persea americana) is an economically significant fruit crop cultivated worldwide, but its production is often constrained by various biotic stresses. Among these, raised fruit spots and anthracnose-like disease, caused by species within the Pestalotiopsis complex, pose a serious threat, leading to substantial yield losses. This study aimed to assess the incidence of raised fruit spots in major avocado-growing regions of Western Ghats, India and identify the Pestalotiopsis species associated with the disease. A total of 75 symptomatic avocado fruit samples were collected from three southern states of India. Microscopic and cultural characterization confirmed the presence of Pestalotiopsis species, and multilocus gene sequencing of 45 isolates using the internal transcribed spacer (ITS), translation elongation factor 1-α (TEF-1α), and β-tubulin (β-tub) regions further elucidated species identity. NCBI-BLASTn analysis and concatenated sequence phylogeny revealed that twenty isolates belonged to Neopestalotiopsis clavispora, twenty to Pestalotiopsis microspora, and five to Pestalotiopsis trachycarpicola. To evaluate disease management strategies, in vitro and field trials were conducted using eleven fungicides. Most tested fungicides exhibited over 50 % inhibition at a minimum concentration of 150 ppm, except for Fenamidone (10 %) + Mancozeb (50 %) WG, which failed to achieve 50 % control even at 1250 ppm. Among the tested fungicides, Hexaconazole 5 % EC and Propiconazole 25 % EC exhibited the highest efficacy. Additionally combination products, Tebuconazole 50 % + Trifloxystrobin 25 % WG, Hexaconazole 4 % + Zineb 68 % WP, Pyraclostrobin 133 g/L + Epoxiconazole 50 g/L w/v SE, and Metiram 55 % + Pyraclostrobin 5 % WG were also effective across all tested concentrations. This study represents the first characterization of Pestalotiopsis species associated with raised fruit spots in avocados in India. The findings provide critical insights into the necessity of timely fungicide applications to mitigate economic losses.