Biologi dan Neraca Hayati Ulat Grayak Jagung, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) pada Babycorn

Abstract

Biologi dan neraca hayati ulat grayak jagung, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) pada babycorn. Ulat grayak jagung, S. frugiperda merupakan hama asing invasif yang telah menimbulkan kerusakan berat pada tanaman jagung di Pasaman Barat, Sumatera Barat pada awal tahun 2019. Informasi mengenai biologi dan neraca hayati S. frugiperda di Indonesia masih terbatas. Penelitian ini bertujuan mengetahui biologi dan neraca hayati S. frugiperda yang dipelihara di laboratorium dengan pakan jagung semi. Larva tahap pertama (110) dipelihara secara individual pada wadah yang berisi babycorn sebagai pakan. Pengamatan dilakukan setiap hari samapi munculnya imago. Imago yang muncul dipasangkan dan dipelihara dalam kurungan yang terpisah. Pengamatan terhadap imago dilakukan setiap hari sampai imago mati. Data yang diperoleh yaitu data stadium, data pengukuran, dan data neraca hayati. Hasil penelitian menunjukkan bahwa rata-rata stadium dari telur, larva 6 instar, pra-pupa, dan pupa berturut-turut adalah 2.47, 14.96, 1.83, 9.75 (jantan), dan 8.81 (betina) hari. Rataan masa pra-oviposisi, oviposisi, pasca-oviposisi, lama hidup imago, dan siklus hidup berturut-turut, yaitu 1.60, 7.90, 2.27, 11.34 (jantan), 11.77 (betina), 37.69 (jantan), dan 37.70 (betina) hari. Telur yang diletakkan imago betina rata-rata sebanyak 1365.86 butir dengan persentase fertilitasnya sebesar 94.68%. Kurva kesintasan S. frugiperda adalah kurva sintasan tipe I, dengan laju reproduksi kotor (GRR) 1442.49 individu per generasi, laju reproduksi bersih (Ro) 1342.77 individu per induk per generasi, laju pertambahan intrinsik (r) 0.23 individu per induk per hari, rataan lama generasi (T) 31.23 hari, dan waktu yang dibutuhkan populasi untuk berlipat ganda (DT) adalah 3.01 hari.

Biology and life table of fall armyworm Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) on babycorn. The fall armyworm, S. frugiperda is an invasive pest that caused serious damage on corn in West Pasaman, West Sumatera, in early 2019. In Indonesia, research and information about this pest still limited. This research aimed to determine the biology and life table of S. frugiperda on babycorn under laboratory condition. First stage larvae (110) were reared individually in the petridish supplied babycorn as feed. Observation were conducted everyday until adult emergence. Emerging adults were paired and reared in separated cages. Observation of adults were conducted everyday until adult death. Results showed that mean developmental duration of egg, 6 instars larvae, pre-pupa, and pupa were 2.47, 14.96, 1.83, 9.75 (male), and 8.81 (female) days, respectively. The periode of pre-oviposition, oviposition, post-oviposition, longevity of adult, and life cycle were 1.60, 7.90, 2.27, 11.34 (male), 11.77 (female), 37.69 (male), and 37.70 (female) days. The average of the eggs laid by female was 1365.86 eggs and a fertility percentage was 94.68 %. The survival curve of S. frugiperda categorized as a type I, with the gross reproduction rate (GRR) of 1442.49 individual per generation, the net reproduction rate (Ro) was 1342.77 individual per female per generation, the intrinsic rate of increase (r) was 0.23 individual per female per day, the mean generation time (T) was 31.23 days, and the population doubling time (DT) was 3.01 days.