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Meloidogyne incognita and Radopholus similis are the primary pathogens that reduce crop losses by up to 60% and cause yellow disease in pepper in Bangka. Consequently, the research aims to know the distribution diversity and population of nematodes, plant parasites, and non-parasites alike and the symptoms of the yellow disease on pepper. This study was carried out by selecting samples of pepper with symptoms of the yellow disease from a field on Bangka Island. Samples of soil and root were taken from three symptomatic plants in each site and repeated three times. Nematodes were extracted from samples and identified based on morphological characters. The results showed that the dominant symptoms of the yellow disease were yellowing of the leaves, stiff and curved towards the stem, small brownish spots and large blackish-brown spots on the leaf surface, yellowing, and severe symptoms until the leaves fall. The nematodes/ 100 ml of soil were Meloidogyne spp. with a total population of 275 individuals, Criconemoides sp. 158.33 individuals, Rhabditida group 1350 individuals, Aphelenchus avenae 25 individuals, and Mononchida group 25 individuals. The nematodes/ 5 g of roots were Meloidogyne spp. with a population of 775 individuals, Radopholus similis 133.33 individuals, and Criconemoides sp. 16.67 individuals.

Indonesia has produced various types of essential oils, one being citronella oil. This essential oil is multi-beneficial not only from its contribution to agricultural development, but is also plays a role in the development of the community’s economy. A large area of agricultural lands of ultisol soil types have not been utilized, therefore a study was conducted on the effect of harvest interval on the productivity of three varieties of citronela grass planted on ultisol soil. This study was conducted from January 2019 to January 2021, with a randomized block design in factorial using two factors. The first factor is harvest interval, with three levels consisting of P1 = a harvest interval of once in 4 months, P2 = a harvest interval of once in 3 months, and P3 = a harvest interval of once in 2 months. While the second factor is variety, with three levels consisting of V1 = Citrona 1 variety, V2 = Citrona 2 variety, and V3 = Serai wangi 1 variety, repeated three times. Each treatment consisted of 24 clumps. The parameters observed were vegetative growth, terna production, oil production, intensity of spot disease attack, and quality analysis R/C ratio. The results of the research on harvest intervals and the three types of varieties used on ultisol soil showed that the best harvest interval was of once every 3 months; while the Serai wangi 1 variety showed good results of vegetative development, had the lowest intensity spot disease attack (24.75 and 19.60%), terna production (68.76 and 59.78 ton –ha-th), and oil production (481.42 and 418.08 kg –ha-th). On another note, oil quality such as Citronella and Graniol content was not affected by harvest interval and the variety used. For the R/C Ratio in the second year of planting, it was revealed that business feasibility was at harvest intervals of once every 3 months with an R/C Ratio of (1.28) on the Serai wangi 1.

This study aims to determine the effect of video-based training to improve the performance of football assistant referee. This study used an experimental method, involving 54 assistant referees who were divided into experimental and control groups. The result shows that the application of video-based training improved the performance of assistant referees. The assistant referees were able to analyze the various mistakes made every time they led a football match. It implies that variation in the training process using video technology is necessary to enhance the performance of football assistant referee.

Unmanned aircraft or UAV (Unmanned Aerial Vehicle) is a future technology that continues to be developing. This research examines the structural vibration acceleration response of the aircraft’s nose landing gear. The landing gear is the part of the aircraft that receives the most significant shock load during landing. This is due to the magnitude of the maximum acceleration of the landing gear vibration when experiencing shock loads. This phenomenon causes the landing gear damaged due to excessive vibration. Therefore, uncontrolled shock loads can damage the landing gear structure and even pierce its frame structure. A momentum transfer method was applied to the landing gear design to reduce the maximum acceleration amplitude of vibration due to experiencing shock loads during landing. The research experiment was carried out using the principle of passive momentum transfer; the test was carried out by dropping the landing gear at a certain height. When the landing gear experiences a shock load, kinetic energy and momentum will be transferred to the PMEID system so that the landing gear remains in a stable condition. The experiment gives an output in the form of the vibration acceleration amplitude of the landing gear measured by the accelerometer sensor on the landing gear’s main mass. The vibration response will then be sent to the voltage amplifier and forwarded to the digital signal processing and displayed on a computer monitor. The test results prove the application of the momentum transfer method in the landing gear design can reduce the maximum amplitude of vibration acceleration when landing.

Understanding the pattern of lepidopteran pest community attacking oil palms and associated parasitoid is very important to develop appropriate biological control strategies. Insects were surveyed by collecting larvae of lepidopteran pests attacking oil palm plantations. Samplings were conducted by diagonal transect walk crossing oil palm blocks. Insects collected from the field were brought into the laboratory and maintained with fresh leaves of oil palm until pupation. Parasitized larvae were intensively observed, and emerging parasitoids were collected for identification. In total, approximately 17 species were identified to attack oil palm by surveying 976 trees from three different age of palm oil plantations. Only 19,98% of which were infested by Lepidopteran pests. Limacodidae was found to be the most specious family inhabiting oil palm plantation of the study area, and Psychidae only represented by two species. Setora niten was recorded to be the most abundant species. Abundance structure of Lepidopteran pests seems to be different for different age of oil palm. S. nitens was found to be dominant in younger oil palm but not in older oil palm. Only four species were found to be parasitized by parasitoid including Birthamula chara, Darna bradley, Darna deducta, Darna trima, and Limantriidae (ulat bulu-3). All parasitoid species attacked the larvae were gregarious belongs to Braconidae and Eulophidae. Euplectrus, gregarious endoparasitoid of Eulophid was found to parasitize D trima. Long term study is needed to understand the complete pattern of host-parasitoid interaction in oil palm plantations.