FLUKTUASI POPULASI HARIAN NGENGAT Spodoptera exigua SEBELUM DAN SELAMA MUSIM TANAM BAWANG MERAH DI LAHAN SURJAN KABUPATEN KULONPROGO

ADITYA WISNU I, Prof. Dr. Ir. F.X. Wagiman, S.U. ; Dr. Ir. Witjaksono, M.Sc.

2019 | Skripsi | S1 PROTEKSI TANAMAN

Kajian lapangan tentang fluktuasi populasi harian ngengat Spodoptera exigua sebelum dan selama musim tanam bawang merah di lahan surjan Kabupaten Kulonprogo dalam musim kemarau bulan Oktober 2018 dan musim penghujan bulan November - Desember 2018. Hujan turun mulai 4 November 2018 dan tanam bawang merah 15 November 2018. Penelitian bertujuan untuk mengetahui dinamika populasi ngengat S. exigua sebelum dan sesudah musim tanam bawang merah serta mengetahui pengaruh arah mata angin terhadap tangkapan populasi ngengat S. exigua. Pengamatan populasi dilakukan setiap hari dalam 30 kali pengamatan pertama dan 3 hari sekali dalam 10 kali pengamatan berikutnya. Perangkap feromon digunakan untuk menjebak ngengat S. exigua yang dipasang pada sembilan titik dalam suatu lingkaran berdiameter 26 m dengan delapan arah mata angin (Utara, Timur Laut, Timur, Tenggara, Selatan, Barat Daya, Barat, Barat Laut) serta pusat, tiga ulangan. Hasil penelitian menunjukkan bahwa populasi ngengat S. exigua sangat tinggi pada 4 hari pengamatan awal saat musim kemarau (12-19 ekor/perangkap) kemudian berfluktuasi semakin berkurang hingga pengamatan terakhir pada musim hujan dan setelah musim tanam bawang merah (0,41 ekor/perangkap). Populasi ngengat S. exigua tidak dipengaruhi signifikan oleh arah mata angin dan berkorelasi negatif (r = - 0,4883) dengan curah hujan.

The field study of daily populations fluctuation of Spodoptera exigua moths before and during onion planting season at “surjan” field in Kulonprogo Regency was carried out in the dry season of October 2018 and the rainy season of November - December 2018. Rainfall started in 4 November 2018 and onion was planted in 15 November 2018. The study aimed to determine the population dynamics of S. exigua moths at before and after the onion planting season and to know the effect of wind direction and rainfall to the S. exigua moth population. Population observation was carried out every day in the first 30 observations and once every 3 days in the next 10 observations. Pheromone traps were used to trap S. exigua moths which were installed at nine points in a circle with a diameter of 26 m with eight wind direction (North, Northeast, East, Southeast, South, Southwest, West, Northwest) and the center, with three replications. The results showed that the population of S. exigua moths was very high at the initial 4 days of observation during the dry season (12-19 moths/traps) then fluctuated to less and less until the last observation in the rainy season and after the onion planting season (0.41 moths/trap). The population of S. exigua moths was not significantly affected by wind direction and negatively correlated (r = - 0.4883) with rainfall.

Kata Kunci : fluktuasi populasi, arah mata angin, bawang merah, Spodoptera exigua