Keefektifan beberapa senyawa kimia sebagai agen penginduksi resistensi tanaman sawi terhadap penyakit bercak daun Curvularia
Authors: Suganda Tarkus , Wulandari Dinda Yulindar 
Published: December 2019

Penyakit bercak daun Curvularia merupakan penyakit baru pada tanaman sawi. Pengendalian penyakit dengan fungisida sintetik sangat berbahaya karena daun sawi dikonsumsi sebagai sayuran mentah atau pengolahan minimal, untuk itu diperlukan alternatif cara pengendalian yang lebih aman bagi kesehatan seperti menginduksi resistensi tanaman menggunakan bahan kimia. Penelitian ini bertujuan untuk mengetahui keefektifan beberapa bahan penginduksi resistensi seperti asam salisilat, kitin, K2HPO4, dan vitamin B1. Sementara, Bion M1/48, bahan penginduksi komersial, digunakan sebagai pembanding. Bahan penginduksi diaplikasikan melalui cara perendaman benih dan disemprotkan. Pada perlakuan perendaman, benih direndam dalam suspensi bahan penginduksi selama 12 jam, sedangkan pada perlakuan penyemprotan, bahan penginduksi disemprotkan satu kali yaitu dua hari sebelum inokulasi dilakukan. Inokulasi patogen yang digunakan memiliki suspensi konidia kerapatan 5 x 105 konidia ml-1. Penelitian ini menggunakan Rancangan Acak Kelompok dengan empat ulangan. Pengamatan dilakukan terhadap masa inkubasi dan intensitas penyakit. Hasil pengujian menunjukkan bahwa perendaman benih asam salisilat, kitin dan K2HPO4, mampu menunda kemunculan gejala sakit lebih lama dibandingkan Bion M 1/48. Terhadap intensitas penyakit, asam salisilat, kitin, dan K2HPO4, juga efektif menginduksi resistensi tanaman sawi terhadap penyakit bercak daun Curvularia. Ketiga senyawa kimia ini potensial untuk digunakan sebagai pengganti fungisida sintetis dalam mengendalikan penyakit bercak daun Curvularia pada tanaman sawi.ABSTRACTCurvularia leaf spot is a new disease on mustard green (Brassica juncea L.). The diseases control with synthetic fungicide is dangerous since mustard green leaves are freshly consumed or with minimum treatments. Therefore, a safer alternative method must be sought such inducing plant resistance using chemical inducers. This research aimed to evaluate effectiveness of salicylic acid, chitin, K2HPO4, vitamin B1, as resistance inducers. Meanwhile, Bion M 1/48, a commercial inducer, was used as the check treatment. These substances were applied as either seed soaking or spraying. In the soaking treatmet, the seeds were soaked for 12 hours duration, whereas in the spraying treatment, chemicals were applied once, at two days before inoculation with conidial suspension of 5 x 105 conidia ml-1. Experimental plants were arranged in a Randomized Block Design with four replicates. Observation was carried out on incubation period and disease intensity. Results showed that soaking the seed in salicylic acid, chitin and K2HPO4 was able to delay the appearance of symptoms, better than of Bion M 1/48. Towards disease intensity, salicylic acid, chitin, and K2HPO4 were also effective in inducing resistance of mustard green leaves against Curvularia leaf spot. The three substances were potential to be applied as an alternative to synthetic fungicide in managing Curvularia leaf spot on the mustard green.