Evaluasi Penyakit Bercak Daun Pada Bibit Johar (Cassia siamea Lamk.) di Nursery PT Indominco Mandiri, Kalimantan Timur

Abstract

Salah satu jenis tanaman yang terserang penyakit bercak daun di nursery PT Indominco Mandiri adalah johar (Cassia siamea Lamk.). Tanaman yang berada di nursery rentan terserang penyakit bercak daun karena jenis tanaman yang seragam serta memiliki jarak tanam yang terlalu rapat sehingga penyakit lebih mudah menular. Tujuan penelitian ini adalah melakukan deteksi penyakit bercak daun serta menghitung insidensi dan keparahan penyakit bercak daun johar di nursery PT Indominco Mandiri. Metode penelitian yang dilakukan meliputi pembuatan blok dan pengamatan gejala bercak daun, evaluasi penyakit, isolasi, pemurnian patogen, dan uji patogenisitas. Hasil penelitian menunjukkan bahwa gejala penyakit bercak daun johar di nursery PT Indominco Mandiri berupa bintik cokelat kehitaman tidak beraturan. Insidensi penyakit bercak daun johar mencapai 100% dan tingkat keparahan penyakit pada blok 1 sebesar 82% (parah), blok 2 sebesar 89% (sangat parah), dan blok 3 sebesar 90% (sangat parah).

One of the plants affected by leaf spot disease in the PT Indominco Mandiri nursery is johar (Cassia siamea Lamk.). The plants in this nursery are particularly vulnerable to leaf spot disease due to their uniform types and close planting distances, which facilitate the spread of the disease. This study aimed to detect the presence of leaf spot disease and to measure its incidence and severity in johar plants at the PT Indominco Mandiri nursery. The research methods included creating observation blocks, monitoring leaf spot symptoms, evaluating the disease, isolating and purifying pathogens, and conducting pathogenicity tests. The findings indicated that the symptoms of leaf spot disease on johar plants were irregular blackish-brown spots. The incidence of the disease was 100%, with severity levels in block 1 at 82% (severe), block 2 at 89% (very severe), and block 3 at 90% (very severe).