Evaluasi Penyakit Bercak Daun pada Daun Bakau (Rhizophora mucronata Lamk) di Kabupaten Indragiri Hilir

Abstract

Bercak daun (Leaf spot) merupakan salah satu penyakit yang menghambat pertumbuhan bibit Rhizophora mucronata. Penelitian ini bertujuan mengevaluasi kejadian dan keparahan penyakit bercak daun bibit R. mucronata serta mengidentifikasi patogen penyebabnya. Metode penelitian meliputi pengamatan kejadian dan keparahan penyakit, laju pertumbuhan penyakit, serta tinggi dan diameter bibit. Pengambilan data dilakukan tiga kali ulangan dengan intesitas sampling 10%. Sampel daun bergejala diisolasi kemudian diuji Postulat Koch dan dilakukan identifikasi patogen. Hasil menunjukkan kejadian penyakit tidak berbeda nyata pada lokasi tidak ternaungi (72,233%) dengan lokasi ternaungi (77,778%). Laju perkembangan penyakit lebih cepat pada bibit tidak ternaungi (0,036 %/hari) dibandingkan ternaungi (0,002/hari). Berdasarkan hasil identifikasi, didapatkan 6 genus cendawan patogen, yaitu Rhizoctonia sp. (isolat RM1-1 dan RM2-4), Pestalotiopsis sp. (isolat RM1-2, RM1-3 dan RM1 4), Bipolaris sp. (isolat RM2-1 dan RM2-2), Curvularia sp. (isolat RM2-3, RM3-2, dan RM3-3), dan Lasiodiplodia sp. (isolat RM3-1) dan Colletotrichum sp. (isolat RM3-4). Masa inkubasi berkisar 3-4 hari, menunjukkan kemampuan infeksi yang cepat.

Leaf spot is one of the diseases that inhibit the growth of Rhizophora mucronata seedlings. This study aims to evaluate the incidence and severity of leaf spot disease in R. mucronata seedlings and identify the causative pathogens. The research methods include observing the incidence and severity of the disease, the rate of disease growth, and the height and diameter of the seedlings. Data collection was carried out three times with a sampling intensity of 10 %. Symptomatic leaf samples were isolated, then tested for Koch's Postulates and pathogen identification was carried out. The results showed that the incidence of the disease was not significantly different in unshaded locations (72,233%) and shaded locations (77,778%). The rate of disease development was faster in unshaded seedlings (0,036%/day) compared to shaded (0,002/day). Based on the identification results, 6 genera of pathogenic fungi were obtained, namely Rhizoctonia sp. (isolates RM1- 1 and RM2-4), Pestalotiopsis sp. (isolates RM1-2, RM1-3 and RM1-4), Bipolaris sp. ( isolates RM2-1 and RM2-2), Curvularia sp. (isolates RM2-3, RM3-2, and RM3-3), Lasiodiplodia sp. (isolate RM3-1) and Colletotrichum sp. (isolate RM3-4). The incubation period ranges from 3-4 days, indicating a rapid infection ability.