Eksplorasi Patogen dan Intensitas Penyakit Bercak Daun pada Bibit Kelapa Sawit Simalungun

Abstract

Kelapa sawit (Elaeis guineensis Jacq) merupakan komoditas unggulan nasional yang berkontribusi besar terhadap perekonomian Indonesia. Namun, tahap pembibitan menjadi fase kritis yang rentan terhadap serangan penyakit, terutama bercak daun. Penelitian ini bertujuan untuk mengidentifikasi jenis patogen penyebab bercak daun, serta mengukur kejadian dan intensitas penyakit di beberapa lokasi pembibitan kelapa sawit di Kabupaten Simalungun. Penelitian dilakukan dengan metode survei lapangan dan identifikasi laboratorium menggunakan pendekatan purposive sampling di enam lokasi pembibitan: PPKS, PTPN IV Bahjambi (pre-nursery dan main-nursery), PTPN IV Belimbingan, PTPN IV Tinjowan, dan kebun masyarakat di Silampuyang. Identifikasi patogen dilakukan melalui pengamatan makroskopis, mikroskopis, serta uji postulat Koch. Hasil penelitian menunjukkan bahwa penyakit bercak daun pada pembibitan kelapa sawit di Simalungun disebabkan oleh Curvularia sp. dan Pestalotiopsis sp., dengan serangan tertinggi di PPKS (50% dan 45%). Lokasi lain seperti PTPN IV dan Silampuyang menunjukkan intensitas bervariasi antara 15% hingga 40% tergantung jenis patogen yang mendominasi. Oil palm (Elaeis guineensis Jacq) is a national leading commodity that contributes greatly to the Indonesian economy. However, the nursery stage becomes a critical phase that is susceptible to disease attacks, especially leaf spots. This study aims to identify the types of pathogens that cause leaf spots, as well as measure the incidence and intensity of diseases in several oil palm nursery locations in Simalungun Regency. The research was carried out using a field survey method and laboratory identification using a purposive sampling approach in six nursery locations: PPKS, PTPN IV Bahjambi (pre-nursery and mainnursery), PTPN IV Belimbingan, PTPN IV Tinjowan, and community gardens in Silampuyang. Pathogen identification was carried out through macroscopic, microscopic, and Koch postulates tests. The results of the study showed that leaf spot disease in oil palm nurseries in Simalungun was caused by Curvularia sp. and Pestalotiopsis sp., with the highest attacks in PPKS (50% and 45%). Other locations such as PTPN IV and Silampuyang showed an intensity varying between 15% to 40% depending on the type of pathogen that predominates.