Perkembangan Penyakit Jamur Akar Putih (Rigidiporus microporus) pada Ekosistem Perkebunan Karet Galang Deli Serdang Sumut

Abstract

WIDYA MINATI. Development of white root fungi (Rigidoporus microporus) Rubber Plantation in Galang, Deli Serdang, North Sumatera. Supervised by BONNY PUTRA WAHYU SOEKARNO and ACHMAD. White root diseases (WRD) inducing by Rigidoporus microporus pathogen is one of the crucial diseases in rubber plantations. It can degrade harvest production in a range of 3 to 15 %. Becoming one of the soil-borne diseases, it has a strong relationship with the rubber plantation ecosystem. The R. microporus pathogen is highly affected by the ecosystem condition. The variation of disease severity in plantations occurred differently in each plantation as ecosystem alteration shapes, making research regarding the WRD development on the rubber plantation was needed to be carried out. This research used a survey method. It was conducted from January to March 2019 at three rubber plantations namely the PTPN III, and two smallholder estates situating at Galang Sub-district, Deli Serdang- North Sumatera. The chemical-soil analysis was taken in the North Sumatera Soil Laboratory of BPTP (Balai Penelitian Tanah). The laboratory-analysis of soil compounds consisted of organic-C, N, P, K, C/N ratio, and pH. Climate and vegetation data were also then investigated. The link between disease severity and soil chemicals was correlated to seek their relationship. Field observations indicate that the WRD attacks happen in all sampling plantations. This is due to the remaining plants found in each sampling plantation becoming the inoculum sources of the WRD. The highest and lowest attacks of WRD occurs on the first and second month accordingly in the PTPN III plantation at sampling plantations of A3 (47% and 53%), and small-holder estates (5% and 5%), respectively. Furthermore, the disease severities also happen in the same plantations namely at plantation A3 of PTPN III on both months (32.5% and 34.2%) and small-holder estates on both months (5% and 5%). The high attack and severity of the disease in the A3 plantation is presumed to cause by the soil containing highly sandy texture generating a high porosity as well. A high porosity supplies enough oxygen for the R. microporus to develop. Furthermore, a high humidity condition in this sampling plantation is designated by the weed vegetation of Nephrolepis bisarrata helping the WRD developed optimally. The correlation analysis between soil chemical compound and the disease severity indicates that the phosphate content and C/N ratio contribute a significant influence in a negative direction. The organic material compound level and nutrients denote an indirect role in the disease development namely providing nutrients for the plant. The lower contents of the C/N ratio and phosphate demonstrates the higher severity level of WRD. This research can be inferred that the development of WRD in the research location is surmised affecting by a high micro-humidity, nutrient compounds, and low organic material on the soil as well as a soil texture with high porosity. Keywords: climate, disease severity, soil chemical, rubber plantation

Penyakit jamur akar putih (JAP) yang disebabkan oleh patogen Rigidoporus microporus merupakan salah satu penyakit penting pada perkebunan karet. Kerugian yang ditimbulkan oleh penyakit ini dapat menurunkan produksi antara 3 -15% terutama di perkebunan rakyat. Sebagai salah satu penyakit tular tanah (soil-borne disease), penyakit JAP memiliki kaitan erat dengan ekosistem perkebunan karet. Perkembangan R. microporus sebagai penyebab penyakit JAP sangat dipengaruhi oleh kondisi ekosistem perkebunan. Hal ini menyebabkan terjadi variasi keparahan penyakit pada perkebunan yang berbeda-beda di setiap wilayah sebagai bentuk variasi ekosistem perkebunan sehingga perlu dilakukan penelitian analisis perkembangan JAP terhadap ekosistem di perkebunan karet. Metode yang dilakukan dalam penelitian ini yaitu dengan metode survei. Penelitian ini dilakukan pada 3 kebun kebun karet milik Perkebunan Nusantara PTPN III dan 2 kebun perkebunan rakyat yang terletak di Kecamatan Galang, Deli Serdang - Sumatera Utara. Penelitian dilaksanakan pada bulan Januari hingga Maret 2019. Analisis kimia tanah dilakukan di Laboratorium Tanah BPTP (Balai Penelitian Tanah Pertanian) Sumatera Utara. Pengamatan yang dilakukan berupa kejadian penyakit, keparahan penyakit, kondisi kebun, analisis kimia tanah (C-Organik, N, P, K, C/N rasio, pH) dan data iklim serta analisis vegetasi. Analisis data yang dilakukan adalah analisis korelasi antara hubungan keparahan penyakit dengan data iklim, analisis vegetasi dan kimia tanah. Hasil pengamatan kejadian penyakit JAP menunjukkan serangan JAP terjadi pada seluruh kebun contoh. Hal ini terjadi karena adanya sisa-sisa tanaman yang ditemukan pada setiap kebun contoh yang menjadi sumber inokulum JAP. Kejadian penyakit tertinggi pada bulan pertama dan bulan kedua berturut-turut pada perkebunan PTPN III di kebun contoh A3 sebesar 47% dan 53% dan kejadian penyakit terendah pada perkebunan rakyat sebesar 5% dan 5%. Hasil pengamatan keparahan penyakit tertinggi juga pada kebun contoh A3 PTPN III sebesar 32.5% dan 34.2% dan keparahan penyakit terendah pada kebun rakyat sebesar 12.5% dan 12.5% Tingginya kejadian dan keparahan penyakit A3 diduga karena tekstur tanah dengan kandungan pasir yang tinggi sehingga porositas tanah juga tinggi. Porositas yang tinggi menyuplai oksigen yang cukup untuk perkembangan R. microporus. Keadaan kelembapan yang tinggi pada lokasi A3 ditandai dengan vegetasi gulma Nephrolepis biserrata sehingga JAP mampu berkembang optimal. Hasil analisis korelasi antara kimia tanah dan keparahan penyakit yaitu kandungan fosfat dan C/N rasio memberikan pengaruh yang nyata dengan korelatif negatif. Tingkat kandungan bahan organik tanah dan unsur hara memberikan peranan secara tidak langsung terhadap perkembangan penyakit yaitu dengan memberikan nutrisi kepada tanaman. Semakin rendah kandungan C/N rasio dan fosfat menunjukkan tingkat keparahan JAP semakin tinggi. Pada penelitian ini dapat disimpulkan bahwa perkembangan JAP di lokasi penelitian diduga dipengaruhi oleh kelembapan mikro yang tinggi, kandungan unsur hara dan bahan organik yang rendah pada tanah serta tekstur tanah dengan porositas yang tinggi.

White root diseases (WRD) inducing by Rigidoporus microporus pathogen is one of the crucial diseases in rubber plantations. It can degrade harvest production in a range of 3 to 15 %. Becoming one of the soil-borne diseases, it has a strong relationship with the rubber plantation ecosystem. The R. microporus pathogen is highly affected by the ecosystem condition. The variation of disease severity in plantations occurred differently in each plantation as ecosystem alteration shapes, making research regarding the WRD development on the rubber plantation was needed to be carried out. This research used a survey method. It was conducted from January to March 2019 at three rubber plantations namely the PTPN III, and two smallholder estates situating at Galang Sub-district, Deli Serdang- North Sumatera. The chemical-soil analysis was taken in the North Sumatera Soil Laboratory of BPTP (Balai Penelitian Tanah). The laboratory-analysis of soil compounds consisted of organic-C, N, P, K, C/N ratio, and pH. Climate and vegetation data were also then investigated. The link between disease severity and soil chemicals was correlated to seek their relationship. Field observations indicate that the WRD attacks happen in all sampling plantations. This is due to the remaining plants found in each sampling plantation becoming the inoculum sources of the WRD. The highest and lowest attacks of WRD occurs on the first and second month accordingly in the PTPN III plantation at sampling plantations of A3 (47% and 53%), and small-holder estates (5% and 5%), respectively. Furthermore, the disease severities also happen in the same plantations namely at plantation A3 of PTPN III on both months (32.5% and 34.2%) and small-holder estates on both months (5% and 5%). The high attack and severity of the disease in the A3 plantation is presumed to cause by the soil containing highly sandy texture generating a high porosity as well. A high porosity supplies enough oxygen for the R. microporus to develop. Furthermore, a high humidity condition in this sampling plantation is designated by the weed vegetation of Nephrolepis bisarrata helping the WRD developed optimally. The correlation analysis between soil chemical compound and the disease severity indicates that the phosphate content and C/N ratio contribute a significant influence in a negative direction. The organic material compound level and nutrients denote an indirect role in the disease development namely providing nutrients for the plant. The lower contents of the C/N ratio and phosphate demonstrates the higher severity level of WRD. This research can be inferred that the development of WRD in the research location is surmised affecting by a high micro-humidity, nutrient compounds, and low organic material on the soil as well as a soil texture with high porosity. Keywords: climate, disease severity, soil chemical, rubber plantation