Kepekaan Erythricium salmonicolor Penyebab Penyakit Jamur Upas pada Kemiri Sunan terhadap Suhu, Cahaya, dan Fungisida

Abstract

ABSTRAKGejala khas penyakit jamur upas ditemukan pada tanaman kemiri sunan (Reutealis trisperma) di Bogor. Penelitian ini bertujuan menentukan cendawan penyebab dan kepekaannya terhadap suhu, cahaya, dan fungisida. Cendawan diidentifikasi berdasarkan karakter morfologi. Inokulum diperoleh dari isolasi jaringan kulit batang terinfeksi. Uji patogenisitas dilakukan dengan menempelkan potongan cabang kemiri sunan yang sudah terkolonisasi pada bibit kemiri sunan dan diinkubasi di rumah kaca. Pengaruh suhu terhadap cendawan dilakukan dengan menanam koloni cendawan uji pada medium agaragar dekstrosa kentang (ADK) dan diinkubasi pada suhu 25-34 °C. Kepekaan cendawan pada cahaya diuji dengan menanam koloni cendawan di dalam labu berisi medium kaldu dekstrosa kentang (KDK) pada shaker (60 rpm) yang terpapar cahaya (400 luks) atau pada kondisi gelap selama 15 hari pada suhu 25 °C. Bobot segar dan kering miselium cendawan yang diperoleh ditimbang. Efikasi tembaga hidroksida dan mankozeb diuji dengan menanam cendawan uji dimedium ADK yang diteteskan fungisida uji dengan konsentrasi 100, 200, 300, 400 dan 500 ppm. Cendawan penyebab jamur upas pada kemiri sunan diidentifikasi sebagai Erythricium salmonicolor berdasarkan karakteristik morfologinya. Pada uji patogenisitas, miselium E. salmonicolor tumbuh dan membentuk jaring laba-laba pada bibit 3 minggu setelah inokulasi. Cendawan uji dapat tumbuh pada semua kisaran suhu yang diuji, tetapi suhu optimum pertumbuhan E. salmonicolor adalah 28 °C. Cahaya tidak berpengaruh nyata terhadap pertumbuhan E. salmonicolor. Mankozeb menekan pertumbuhan koloni E. salmonicolor lebih baik dibanding tembaga hidroksida.Kata kunci: identifikasi morfologi, mankozeb, tembaga hidroksida, uji patogenisitas ABSTRACT A typical pink disease symptom appeared on stem of Reutealis trisperma in Bogor. The present study was aimed for confirming the causal pathogen and testing its sensitivity to temperature, light and fungicides. The fungus was identified based on its morphological characteristics. The fungal inoculum was obtained by tissue isolation of infected stem bark. For pathogenicity test, the fungus was inoculated onto sterilized pieces of woody R. trisperma branch, then fastened on the seedlings and incubated in the green house. The effect of temperatures on fungal growth was tested by planting the fungal colony onto potato dextrose agar (PDA) then incubated at 25-34 °C. The sensitivity of the fungus to light was tested by inoculating the fungus into flask with potato dextrose broth (PDB) medium on a shaker (60 rpm) exposing it to white light tube (400 luks) or in a dark condition for 15 days at 25 °C. The obtained J Fitopatol IndonesFlorina et al 36 fungal colonies were weighed. Efficacy of copper hydroxide and mancozeb against the fungal colony growth was tested by inoculating the fungus onto PDA amended with 100, 200, 300, 400, and 500 ppm, respectively, of tested fungicides. The results showed that the causal pathogen was Erythricium salmonicolor. In the pathogenicity test, cobwebs of E. salmonic...

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“…Colonies growing on PDA for five days were white with clear concentric circles ( Figure 4E). Conidia were also found on rubber rods (Florina et al, 2017). However, conidia or sporulation structures were not observed on the colonies growing on PDA (Kwarteng et al, 2018;Akrofi et al, 2015).…”

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