Judul: Impact of Rice Straw Incorporation and Insecticide Application on Insect and Spider Biodiversity and  Brown Planthopper Populations
Abstrak: Biodiversity in agricultural ecosystems plays a crucial role in maintaining ecological balance and supporting increased food crop production. In Indonesia, especially in rice cultivation, there is a tendency to make agroecosystems fragile, thereby increasing the potential for the explosion of pest populations, such as the brown planthopper (BPH). One potential solution to enhance the health of rice plants is to return straw after harvest to agricultural fields. This step contributes to maintaining the balance of paddy ecosystems and improving crop production. Optimizing straw incorporation can be enhanced by judiciously applying appropriate and wise insecticides. Therefore, this study aims to investigate the effects of returning organic material, namely rice straw, and applying insecticides with different spectrums and selectivities to rice cultivation. The impacts are observed on soil nutrient content, microbial activity, plant growth, insect and spider diversity, the dynamics of the main pest, BPH population and their effects on yield. Observations of the interaction between straw incorporation and insecticide application were made during two different planting seasons in the experimental field of PT Corteva Agriscience Indonesia, located in Ciwaringin Village, Lemahabang, Karawang Regency, West Java, from January to September 2022. The research design utilized a split-plot design, with two main plots (with and without straw incorporation) and three subplots (without insecticide, broad-spectrum fipronil insecticide, and narrow-spectrum triflumezopyrim insecticide. Soil nutrient and microbial samples were collected by taking soil samples from each plot after planting the land. Insect and spider samples were taken every two weeks using suction devices and insect nets, while BPH population observations were conducted every week until one week before harvest. The overall research results indicate that straw incorporation elicits a positive response regarding plant growth, insect and spider diversity, reduced pest insect populations, and increased natural enemy populations. However, the level of this positive response is influenced by the planting season. Conversely, applying narrow-spectrum insecticides is more effective in protecting rice plants from BPH infestation, positively impacting increased yields. In conclusion, the combination of straw incorporation and triflumezopyrim insecticide application is expected to provide better results for rice protection against BPH infestations., Keanekaragaman hayati dalam ekosistem pertanian memainkan peran penting dalam menjaga keseimbangan ekologi dan mendukung peningkatan produksi tanaman pangan. Di Indonesia, khususnya pada budi daya padi, ada kecenderungan membuat agroekosistem menjadi rapuh, sehingga meningkatkan potensi peledakan populasi hama seperti wereng batang cokelat (WBC). Salah satu solusi potensial untuk meningkatkan kesehatan tanaman padi adalah mengembalikan jerami sisa panen ke lahan pertanian. Langkah ini tidak hanya dapat menjaga keseimbangan ekosistem padi sawah secara tidak langsung, tetapi juga dapat meningkatkan produksi tanaman. Optimalisasi pengembalian jerami dapat ditingkatkan dengan penggunaan insektisida yang tepat dan bijaksana. Oleh karena itu, penelitian ini bertujuan untuk memahami pengaruh dari pengembalian bahan organik berupa jerami dan aplikasi insektisida dengan spektrum dan selektivitas yang berbeda pada pertanaman padi dengan mengamati pengaruhnya terhadap kandungan unsur hara dan mikroba tanah, pertumbuhan tanaman, keanekaragaman artropoda, dinamika populasi hama utama, yaitu WBC, hingga pengaruhnya terhadap hasil panen. Pengamatan interaksi antara pengembalian jerami dan aplikasi insektisida diamati pada dua musim tanam yang berbeda di lahan percobaan PT Corteva Agriscience Indonesia, Desa Ciwaringin, Lemahabang,
Keyword: agroecosystem, fipronil, organic material, triflumezopyrim

Judul: Parasitization Levels and Species of Egg Parasitoid on Yellow Rice Stem Borer (Scirpophaga incertulas) at Paddy Field, Karawang District
Abstrak: Produksi padi di Indonesia masih mengalami penurunan signifikan yang disebabkan oleh organisme pengganggu tanaman (OPT), salah satunya adalah penggerek batang padi kuning (PBPK), Scirpophaga incertulas. Pengendalian hama tersebut yang umum dilakukan oleh petani adalah penggunaan insektisida. Aplikasi insektisida apabila dilakukan dengan tidak bijaksana akan berdampak negatif. Oleh karena itu, perlu dilakukan pengendalian hama yang ramah lingkungan sesuai konsep pengendalian hama terpadu (PHT) seperti aplikasi feromon sintetik. Penelitian ini bertujuan mengetahui tingkat parasitasi dan spesies parasitoid telur S. incertulas pada pertanaman padi yang mendapat perlakuan feromon sintetik (Z11-Hexadecenal 33%). Penelitian ini dilakukan di pertanaman padi milik petani di Desa Sukaraja, Kecamatan Rawamerta, dan Desa Sindangmukti, Kecamatan Kutawaluya, Kabupaten Karawang, Jawa Barat mulai dari Februari sampai Juni 2020. Penelitian dilakukan pada lahan 80 ha yang dibagi menjadi beberapa petak lahan. Percobaan dilakukan menggunakan rancangan acak kelompok (RAK) dengan 4 perlakuan dan 5 ulangan. Perlakuan yang digunakan yaitu perlakuan kontrol (pertanaman padi tanpa feromon) dan perlakuan feromon dengan dosis 10 dispenser/ha, 20 dispenser/ha, dan 30 dispenser/ha. Pengambilan kelompok telur dilakukan setiap 2 minggu sebanyak 4 kali. Peubah yang diamati yaitu kemunculan larva PBPK dan imago parasitoid, serta tingkat parasitisasinya. Hasil penelitian ini menunjukkan bahwa penggunaan feromon sintetik dapat memengaruhi tingkat parasitasi kelompok telur pada pengamatan 10 MST dan tingkat parasitasi butir telur pada pengamatan 6 MST, tetapi tidak memengaruhi terhadap jumlah larva PBPK yang menetas, imago parasitoid yang muncul, dan spesies parasitoid yang ditemukan., The rice production in Indonesia have significant declined due to plant pests and diseases, one of them is yellow rice stem borer (PBPK) Scirpophaga incertulas. Insecticide applications have been commonly used by farmers for controlling this pest. Unwise application of insecticides will have a negative impact. Therefore, integrated pest management (IPM) needs to be carrierd out and one of strategy is synthetic pheromone application. This research aims to determine the type of egg parasitoids and its parasitization level of S. incertulas in paddy field applied by synthetic pheromones (Z11-Hexadecenal 33%). This research was carried out in farmers' rice fields at Sukaraja Village, Rawamerta District, and Sindangmukti Village, Kutawaluya District, Karawang Regency, West Java from February to June 2020. The research was carried out on 80 Ha of land which was divided into several plots of land. The experiment was conducted using a randomized group (RBD) with 4 treatments and 5 replications. The treatments used were control treatment (rice cultivation without using pheromone) and treatment of rice planting with 10 dispenser/ha, 20 dispenser/ha, and 30 dispenser/ha. Eggs were sampled biweekly for 4 times with variables were observed of the appearance of PBPK larvae, parasitoid imago, and parasitization levels. The results of this study indicated that the use of synthetic pheromones affected the parasitization levels of egg group at 10 MST and parasitization levels of egg at 6 MST, but does not affected the number of hatched PBPK larvae, emerge parasitoids adults, and parasitoid species found.
Keyword: egg parasitoids, paddy, Scirpophaga incertulas, synthetic pheromones

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
Keyword: