New Distribution and Recent Spread of Ceratocystis Disease in Duku Plantations of South Sumatra

The lethal wilt disease on Lansium domesticum was first reported in 2014 and was initially found only in Ogan Komering Ulu Regency. From 2019 to 2021, the disease has spread widely across several major duku plantation areas in South Sumatra, including Ogan Komering Ulu Selatan, Musi Banyuasin, Ogan Komering Ilir, Musi Rawas, Musi Rawas Utara, and a small portion of L. domesticum plantations in Muara Enim, with varying levels of severity. Currently, the disease attack has become increasingly severe, spreading extensively across plantations in Muara Enim. This study aims to determine the distribution, severity, and genetic variation of Ceratocystis in Muara Enim. Eight Ceratocystis isolates were successfully obtained from diseased L. domesticum sapwood tissues and were identified morphologically and through molecular analysis using internal transcribed spacer (ITS) and β-tubulin markers, which revealed that Ceratocystis fimbriata is responsible for the lethal wilt disease on L. domesticum in Muara Enim. Koch’s postulates were confirmed, and host range tests showed that the isolates exhibited varying pathogenicity across all tested plants. These results indicate that Ceratocystis poses a serious threat to all duku plantations, and therefore, disease control measures must be implemented immediately to prevent the extinction of this plant as part of the biodiversity of South Sumatra.