Judul: The Attack of the Brown Planthopper in Purwabakti Village and its Relation to Cultivation Techniques by Farmer
Abstrak: The population's outbreak of the brown planthopper occurred for the first time in Purwabakti Village, Bogor Regency during the 2020/2021 rice planting season. The factors related to this phenomenon has not been reported yet. Field research which included observing the level of plot damage, interviewing rice cultivation techniques by farmers, and exploring the diversity of endophytic fungi on rice stems was carried out with the aim of analyzing cultivation techniques related to the level of plot damage and knowing the diversity of endophytic fungi on rice stems. Observation of the level of damage to plots was carried out by estimating the percentage of damage to plots based on the appearance of visual symptoms of damaged plots due to planthopper attack. Information on rice cultivation practices was collected by interview technique. Isolation of endophytic fungi was carried out on samples of rice stems in damaged and undamaged plots. Data analysis was done by descriptive method through cross tabulation approach. The relation between cultivation techniques and the level of plot damage was analyzed by Chi-square test with a significance level of 5%. Based on the results of the study, the cultivation technique factors that were significantly related to the level of plot damage due to WBC attack in Purwabakti Village were rice variety, dose of N fertilizer, use of K fertilizer, and burning of straws. The level of moderate, severe, and puso damage was mostly found in the plots planted with IR Kebo rice varieties, plots that were given high doses of N fertilizer, plots that were not given K fertilizer, and plots where straw was burned. The diversity of endophytic fungi on rice stalks is low. The results of the isolation of endophytic fungi found three isolates that were suspected to have mutualistic potential for plants, namely HN 1, HN 2, and PN 2.
Keyword: brown planhopper, population’s outbreak, rice, endophytic fungi, rice

Judul: SURVEY OF DISTRIBUTION OF BROWN PLANTHOPPER POPULATION IN RICE CROPS IN SUBANG REGENCY WEST JAVA
Abstrak: Padi (Oryza sativa L.) merupakan komoditas penting sebagai sumber pangan pokok di Indonesia. Budidaya tanaman padi seringkali mengalami kegagalan akibat serangan hama wereng batang cokelat (WBC) Nilaparvata lugens Stål. Penelitian ini bertujuan mengetahui persebaran populasi WBC di Kabupaten Subang, kerapatan populasinya, dan tingkat kerusakan tanaman padi di tiga lokasi ketinggian tempat yang berbeda. Penelitian ini dilakukan dengan menelusuri keberadaan serangan WBC di lahan persawahan di areal kabupaten Subang dan memetakan persebarannya, menentukan lahan perlakuan terinfestasi di tiga lokasi ketinggian tempat berbeda, mengamati tingkat kerusakan tanaman pada umur 4 MST dan kerapatan populasi WBC. Data penunjang diperoleh melalui wawancara terhadap petani tentang teknik budidaya padi setempat kaitannya dengan pengendalian WBC di lahannya. Luas serangan dan intensitas kerusakan tanaman tertinggi 91,5% dan 41%, dengan jumlah populasi WBC tertinggi 1.8 ekor/rumpun ditemukan di lahan padi dataran rendah pada ketinggian 27-38 m dpl, sebaliknya kerusakan paling rendah sebesar 22% dan 4.3% dengan jumlah populasi 0.35 ekor/rumpun ditemukan di dataran tinggi pada 516-526 m dpl. Penggunaan varietas padi Ciherang dan Inpari 31 tidak berpengaruh terhadap jumlah populasi WBC. Lokasi penanaman padi di dataran rendah dengan curah hujan dan suhu lingkungan yang tinggi berkontribusi dalam peningkatan populasi WBC, Rice (Oryza sativa L.) is an important commodity as the staple food in Indonesia. Rice cultivation often fails due to attacks by the brown planthopper (BPH) Nilaparvata lugens Stål. This study aims to determine the distribution of BPH population in Subang Regency, the population density, and the level of damage to rice crops at three different altitude locations. This research was conducted by tracing the presence of BPH infestation in paddy fields in the Subang district area and mapping their distribution, determining the infested treatment areas at three different altitude locations, observing the level of plant damage at 4 WAP and the population density of BPH. Supporting data was obtained through interviews with farmers regarding local rice cultivation techniques in relation to BPH control in their fields. The highest attack area and intensity of crop damage were 91.5% and 41%, with the highest number of BPH populations of 1.8 individuals/hills found in lowland rice fields at an altitude of 27-38 masl, whereas the lowest damage was 22% and 4.3% with the lowest populations of 0.35 individuals/hills found in the highlands at 516-526 masl. Ciherang and Inpari 31 rice varieties had no effect on the number of WBC populations. The location of rice cultivation in the lowlands with high rainfall and ambient temperature contributed to the increase in the BPH population.
Keyword: Intensitas, Ketinggian tempat, Luas serangan, Varietas padi, Altitude, Attack area, Intensity, Rice varieties

Judul: Penentuan energi aktivasi ion untuk melewati membran teflon pada berbagai larutan elektrolit
Abstrak: Kaseno (1999) menyatakan bahwa dalam teknologi pemisahan, membran adalah bahan yang dapat memisahkan dua komponen dengan cara yang spesifik yaitu menahan atau melewatkan salah satu komponen lebih cepat dari komponen lainnya. Kemampuan pemisahan yang dimiliki oleh membran untuk melewatkan suatu senyawa kimia atau molekul diakibatkan oleh adanya perbedaan sifat fisika atau kimia antara membran dengan senyawa kimia.
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