Genus Curvularia and Pestalotiopsis as the primary pathogen of leaf spot disease on oil palm seedlings throughout Indonesia

Abstract Leaf spot is a major plant disease that affects oil palm seedlings. Several fungal genera, including Cercospora, Curvularia, Drechslera, Pestalotiopsis, and Phyllosticta, have been linked to leaf spot disease in oil palms worldwide. A survey was undertaken in several oil palm nurseries throughout Indonesia to discover the primary pathogen of the leaf spot disease. The result revealed that two dominating genera, Curvularia and Pestalotiopsis, were responsible for leaf spot infections on oil palm seedlings in Indonesia. Curvularia was isolated from oil palm nurseries in Sumatra, Java, Kalimantan, and Sulawesi. Curvularia isolates can be divided into five morphotypes based on colony growth and appearance. On the other hand, three major morphotypes of Pestalotiopsis were collected from Sumatra, Java, Kalimantan, Sulawesi, and Papua.