KARAKTERISASI Erwinia chrysanthemi PENYEBAB PENYAKIT BUSUK BAKTERI PADA DAUN LIDAH BUAYA (Aloe vera)

Penyakit busuk (soft rot) pada daun tanaman lidah buaya (Aloe vera) disebabkan oleh F.rwima chrysanthemi pertama kali dilaporkan di Kcpulauan Kaibia tahun 1992. Pada awal tahun 2001, gejala pcnyakil busuk daun juga ditemukan pada tanaman lidah buaya di Semplak, Jawa Barat. Mengingat kerusakan yang ditimbulkan berupa pembusukan pada daun dan pangkal batang yang parah dalam waktu singkat, maka diduga penyebabnya cukup ganas dan dikhawatirkan dapat menjadi kendala pengembangan tanaman lidah buaya yang akhir-akhir ini sedang banyak diminati. Tujuan penelitian ini adalah mengidcntifikasi penyebab penyakit tersebut. Penelitian dilakukan di Laboratorium Bakteri Balai Penelitian Tanaman Rempah dan Obat, dari bulan April - Agustus 2001. Contoh daun lidah buaya sakit berasal dari kebun petani di Semplak, Bogor. Setelah melalui pengamatan gejala penyakit diikuti dengan prosedur isolasi dan pemumian patogen. maka diperoleh isolat kultur baktei yang bentuknya bulat dan pinggirnya tidak rata serta berwarna putih pada medium sukrosa pepton agar. Kultur baktei tersebut bersifat patogenik dan menimbulkan gejala penyakit sama seperti di lapangan, setelah diinokulasikan melalui pelukaan pada daun lidah buaya. Hasil karaktcrisasi morfologi, kultur dan biokimia isolat baktei tersebut menunjukkan sifat ncgatif untuk pewamaan Gram, pigmen fluorescn, oksidasc, dan produksi asam dari unsur karbon laktosa dan dulsitol. Sedangkan karaktcr positif diperoleh dai pengujian oksidasi/fermentasi, lesitinase, pembusukan jaringan umbi kentang, sensitivitas terhadap eitromisin, pertumbuhan pada suhu 37° C, NaCI 5%, serta menghasilkan asam pada medium mengandung manitol Inokulasi pada umbi ubi jalar menyebabkan pembusukan dalam waktu yang singkat. Berdasarkan data tersebut dapat disimpulkan bahwa penyebab penyakit busuk daun pada tanaman lidah buaya di Semplak adalah Erwinia chrysanthemi.Kata kunci: Aloe vera, busuk daun, Erwinia chrysanthemi, Bogor ABSTRACT Characteristics o/Envinia chysanthemi causing bacterial soft rot ofAloe (Aloe VeraJThe bacterial sot rot of aloe, caused by Erwinia chrysanthemi, was first identified in Caibbean Island in 1992. In early 2001, similar symptoms were found on the aloe plants grown in Semplak, Bogor, West Java. Based on its symptom and progressively spread, especially on the leaf and basal stem, it appeared that the disease was serious and therefore threatened the current development of die plants. This study was conducted in the laboratory of the Research Institute for Spice and Medicinal Crops, Bogor, in April - August 2001. The objective of the study was identifying the cause of the sot rot disease of aloe in Semplak, Bogor. Diseased leaves of aloe were obtained from Semplak. Following the examination of the symptoms, isolation and purification of he causal agent, the bacteial isolates were found. They were round, white colony characteistics on sucrose peptone agar medium. The isolate was pathogenic and caused similar disease symptoms following the artificial inoculation on the wounded aloe leaf. Based on the morphological, cultural, and biochemical analyses of the isolates, it was found that the isolates gave negative reactions for die following characteistics: Gram staining, production of fluorescent pigment, oxidase, and production of acid reaction from lactose and dulcitol. The isolates, on the other hand, gave positive reaction from: oxidation/fermentation, IcciOiinase. and maceration of potato and sweet potato, sensitive to crythromycin, growth at 37 °C, and growth on agar medium containing NaCI 2%, as well as acid production from manmtol. Based on these data, it can be concluded that the pathogen causes sot rot of leaf of aloe in Semplak is Erwinia chrysanthemi. This is the irst repot on (he finding of die disease in Indonesia. More attention is required to stop the spread of the disease.Key words: Aloe vera, sot rot. Erwinia chrysanthemi, Bogor