PATOGENISITAS NEMATODA Heterorhabditis sp. TERHADAP KUMBANG DAUN KELAPA Brontispa longissima GESTRO

Abstract

<p>ABSTRAK<br />Suatu bioassay telah dilakukan di Balai Penelitian Tanaman<br />Rempah dan Obat Bogor, dari bulan November 2010 sampai dengan Maret<br />2011, yang bertujuan untuk mengetahui potensi Heterorhabditis sp. dalam<br />mengendalikan Brontispa longissima. Nematoda dipanen dengan cara<br />meletakkan larva Tenebrio molitor mati terinfeksi nematoda patogen<br />serangga (NPS) di atas kertas saring yang diletakkan di dalam cawan petri<br />berisi 30 ml air. Juvenil infektif (JI) yang ada di dalam tubuh larva akan<br />keluar dan hidup di dalam air. Suspensi JI kemudian dilarutkan 1.000 kali<br />lalu populasinya dihitung di bawah mikroskop binokuler dan diulang 3<br />kali. Populasi JI diperoleh dengan melarutkan 10 ml suspensi dengan<br />sejumlah air sehingga diperoleh populasi 7.000, 3.500, 1.750, 875, 438,<br />dan 0 JI/ml air. Masing-masing perlakuan diujikan pada 10 ekor larva,<br />pupa, dan imago dengan menyemprotkan 2 ml suspensi JI. Pengamatan<br />mortalitas B. longissima dilakukan pada 24, 48, dan 72 jam setelah<br />infestasi (JSI). Hasil penelitian menunjukkan bahwa patogenisitas<br />Heterorhabditis sp. tertinggi pada stadia larva diikuti imago dan pupa.<br />Pada populasi 3.500 JI/ml air kematian larva, imago, dan pupa pada 24 JSI<br />berturut-turut sekitar 73, 63, dan 10%, berbeda tidak nyata dengan<br />perlakuan 7.000 JI/ml air. LC 50 Heterorhabditis sp. terhadap larva, imago,<br />dan pupa pada 72 JSI berturut-turut 1.492, 2.622, dan 800.818 JI/ml air.<br />Kata kunci: Brontispa longissima, kelapa, Heterorhabditis sp.,<br />patogenisitas</p><p>ABSTRACT<br />In order to evaluate the potensial of Heterorhabditis sp. in<br />controlling B. longissima bioassays was conducted in Indonesian<br />Research Institute for Spices and Medicinal Crops, Bogor from November<br />2010 until March 2011. Infective juveniles (IJ) of the nematodes were<br />harvested by putting dead Tenebrio molitor on a filter paper placed in a<br />petri dish containing 30 ml of water. IJs in the larval body will then go out<br />and live in the water. The suspension was then diluted 1,000 times and<br />then population counted under a binocular microscope and repeated 3<br />times. IJ population is obtained by dissolving 10 ml suspension to obtain<br />7,000; 3,500; 1,750; 875; 438; and 0 IJs/ml of water. Each treatment was<br />tested on 10 larvae, pupae, and adults by spraying 2 ml IJ suspension.<br />Mortality observations were made at 24, 48, and 72 hours after infestation<br />(HAI). The results showed that the highest Heterorhabditis sp.<br />pathogenicity was found in larvae stadium followed by pupae and adult<br />stadia. In the 3,500 IJ population/ml of water, larvae, imago, and pupae<br />mortalities in 24 HAI were approximately 73, 63, and 10%, respectively<br />and were not significantly different with 7,000 IJ/ml of water. LC 50 values<br />of Heterorhabditis sp. on the larvae, adult, and pupae in 72 HAI were<br />1,492; 2,622; and 800,818 IJ/ml of water, respectively.<br />Key words: Brontispa longissima, Cocos nucifera, Heterorhabditis sp.,<br />pathogenicity</p>