Judul: Infestation of Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) on Maize Plantations in Morotai Island, North Moluccas
Abstrak: Ulat gerayak jagung Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) merupakan hama invasif yang berasal dari Benua Amerika. Pada tahun 2019, S. frugiperda dilaporkan telah menyerang pertanaman jagung di Indonesia tepatnya di Kabupaten Pasaman Barat, Sumatra Barat dengan tingkat serangan berat. Persebaran hama ini semakin meluas ke berbagai wilayah di Indonesia termasuk ke wilayah Pulau Morotai, Maluku Utara. Penelitian ini bertujuan mengetahui jalur masuk, luas serangan, dan intensitas serangan S. frugiperda pada pertanaman jagung di Pulau Morotai, Maluku Utara serta merekomendasikan tindakan pengendalian. Penelitian dilaksanakan pada bulan Agustus hingga Desember 2020. Pengamatan dilaksanakan di dua lokasi yaitu di pertanaman jagung konvensional Desa Sambiki Baru dan di pertanaman jagung organik Desa Dehegila. Pengamatan luas dan intensitas serangan dilakukan setiap minggu pada umur tanaman 2 MST hingga 9 MST. Ulat gerayak jagung S. frugiperda terbawa tongkol jagung masuk ke Pulau Morotai melalui kapal dari Halmahera Utara. Luas serangan pada tanaman jagung konvensional tertinggi sebesar 78,14%, sedangkan pada jagung organik tertinggi sebesar 40,98%. Intensitas serangan pada tanaman jagung konvensional tertinggi sebesar 48,98%, sedangkan pada jagung organik tertinggi sebesar 31,6%. Tindakan pengendalian yang baik dapat dilakukan dengan penggunaan insektisida yang tepat sasaran dengan kombinasi strategi pengendalian lainnya., Fall armyworm Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) is an invasive pest native to the Americas. In 2019, S. frugiperda was reported to have attacked maize crops in Indonesia, precisely in West Pasaman Regency, West Sumatra with a heavy attack rate. The spread of this pest is increasingly widespread in various regions in Indonesia, including the Morotai Island region, North Moluccas. This study aims to provide information about port of entry, attack area, and intensity of S. frugiperda in maize on Morotai Island, North Moluccas and recommends pest management. The research was conducted from August to December 2020. The observations were carried out in two locations, namely in the conventional corn plantation in Sambiki Baru Village and in the organic maize plantation in Dehegila Village. Observation of the area of attack and intensity carried out every week starting when the maize plants were 2 WAP to 9 WAP. Fall armyworm S. frugiperda was carried with the corn cobs into Morotai Island via boat from North Halmahera. The highest attack area on conventional maize was 78,14%, while the highest for organic corn was 40,98%. The highest attack intensity on conventional maize was 48,98%, while the highest was 31,6% for organic corn. Pest management can be taken with targeted insecticides in combination with other control measures.
Keyword: fall armyworm, first report, port of entry

Judul: Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) Attacks and Its Parasitoids on Corn Cultivation in Situ Gede Village, West Bogor District, Bogor, West Java
Abstrak: Jagung merupakan tanaman pangan dan bahan baku industri yang penting di Indonesia. Produksi jagung sangat terpengaruh dengan adanya serangan hama invasif baru di Indonesia yaitu ulat grayak jagung (UGJ) atau fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Pemanfaatan musuh alami merupakan salah satu metode pengendalian yang dapat digunakan. Penelitian ini bertujuan mengetahui tingkat serangan dan parasitoid S. frugiperda yang ditemukan pada pertanaman jagung di Kelurahan Situ Gede, Kecamatan Bogor Barat, Bogor, Jawa Barat. Pengamatan dilakukan sejak tanaman berumur dua minggu setelah tanam (MST) hingga 10 MST dengan interval dua minggu pada 100 tanaman sampel. Larva S. frugiperda dikumpulkan dari plot sampel lalu dipelihara dan diamati, kemudian parasitoid yang muncul dihitung tingkat parasitisasi dan diidentifikasi. Tingkat serangan UGJ meningkat sejak tanaman jagung berumur dua MST hingga delapan MST dan serangannya konstan hingga 10 MST. Intensitas serangan S. frugiperda tertinggi sebesar 64,40% yang termasuk kategori sangat berat. Parasitoid yang ditemukan yaitu Cotesia sp., Microplitis sp. (Hymenoptera: Braconidae), Charops sp. (Hymenoptera: Ichneumonidae), dan Phoridae (Diptera). Tingkat parasitisasi tertinggi oleh Microplitis sp. sebesar 6,72%., Corn is an important food crop and industrial raw material in Indonesia. Corn productivity is greatly affected by the attack of a new invasive pest in Indonesia, fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Using natural enemies is one of the methods to control this pest. This study aimed to determine the plant damages caused by FAW and its natural enemies on corn cultivation at Situ Gede Village, West Bogor District, Bogor, West Java. Observations have been done from two weeks after planting (WAP) to ten WAP with two-week intervals. The plant damage of S. frugiperda was observed on 100 plant samples. The larvae of S. frugiperda were collected from other plant samples and reared in the laboratory until the parasitoids emerged. The parasitoids were then identified. The plant damages increased until the corn cultivation was eight WAP, and the plant damages were constant until harvest. The most severe plant damage of S. frugiperda reached 64.40% and was included in the very heavy category. The parasitoids found during the study were Cotesia sp., Microplitis sp. (Hymenoptera: Braconidae), Charops sp. (Hymenoptera: Ichneumonidae), and Phoridae (Diptera). The highest level of parasitization was Microplitis sp., with 6.72%.
Keyword: fall armyworm, natural enemies, plant damages

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology