Perkembangan dan Perilaku Kawin Penggerek Batang Padi Kuning, Scirpophaga incertulas Walker, pada Tiga Varietas Padi

Abstract

Scirpophaga incertulas is one of important insect in Indonesia that infest rice plant from vegetative to generative phase. Several planted rice varieties in Indonesia are Pelita, IR42, and Cisadane. Rice variety of IR42 and Cisadane have resistant gene for brown plant hopper, but all three varieties are not resistant for yellow rice stem borer. This research was aimed to study the development of S. incertulas on rice varieties of IR42, Cisadane, and Pelita and observe their mating behaviour. Those three rice varieties were planted for 45 days with two weeks planting interval. The first larvae inoculation was carried out at day 45 after plantation and reared at greenhouse until imagoes emergence. One pairs of imago S. incertulas was put in plastic cup. Mating behaviour was recorded in the dark room using infrared handycam. Imago S. incertulas was started emergence at day 36 after inoculation larvae. Male imago was emerged 1-4 days earlier than female. Ranging day emergence of imago was started from 15-21 days. The lowest total number imagoes emerged was from rice variety of Cisadane, whereas almost the same number of imagoes emerged from rice varieties of IR42 and Pelita. Mating behaviours of S. incertulas were commenced by female calling followed by male premating activity and end by copulation. Male moth was responded the female calling by approaching the females for copulation. Copulation of the moth observed in one hour at 03:00-04:00 am. The information of mating behaviour can be used as bio-control of S. incertulas by mating disruption methods with synthetic pheromone.

Scirpophaga incertulas merupakan salah satu serangga penting pada tanaman padi di Indonesia dan dapat menginfestasi tanaman dari stadia vegetatif sampai generatif. Beberapa varietas padi yang dikenal di Indonesia diantaranya adalah varietas Pelita, IR42 dan Cisadane. Padi varietas IR42 dan Cisadane memiliki gen yang tahan terhadap wereng batang coklat namun ketiga varietas belum ada yang tahan terhadap penggerek batang padi kuning. Penelitian ini bertujuan untuk mempelajari perkembangan larva menjadi imago S. incertulas pada padi varietas IR42, Pelita dan Cisadane dan mengamati perilaku kawin serangga tersebut. Ketiga varietas padi ditanam secara bergilir dengan interval 2 minggu selama 45 hari. Inokulasi larva penggerek instar 1 dilakukan pada umur padi 45 hari dan dipelihara di rumah kaca sampai imago keluar. Sepasang imago S. incertulas dimasukkan ke dalam gelas plastik untuk diamati. Perilaku kawin S. incertulas direkam di ruang gelap menggunakan handicam infra merah. Imago S. incertulas mulai keluar pada hari ke-36 setelah inokulasi larva. Imago jantan keluar 1-4 hari lebih cepat daripada imago betina dengan rentang hari keluar adalah 15-21 hari. Jumlah imago S. incertulas keluar paling rendah pada padi varietas Cisadane, sedangkan pada varietas IR42 dan Pelita hampir sama. Tahaptahap perilaku kawin S. incertulas antara lain betina calling, aktivitas jantan sebelum kawin (kopulasi) dan kopulasi. Serangga jantan merespon serangga betina yang sedang calling dengan mendekati serangga betina untuk kopulasi. Kopulasi diamati selama 1 jam antara pukul 03:00- 04:00. Informasi tentang perilaku kawin S. incertulas dapat dimanfaatkan sebagai biokontrol serangga ini dengan metode penghambatan kawin menggunakan feromon sintetik.