Honey bees are crucial pollinators for agricultural and natural ecosystems, but are experiencing heavy mortality in Korea due to a complex suite of factors. Extreme winter losses of honey bee colonies are a major threat to beekeeping but the combinations of factors underlying colony loss remain debatable. Finding solutions involves knowing the factors associated with high loss rates. To investigate whether loss rates are related to Varroa control and climate condition, we surveyed beekeepers in korea after wintering (2021–2022 to 2022–2023). The results show an average colony loss rate of 46%(2022) and 17%(2023), but over 40% colony loss before wintering at 2022. Beekeepers attempt to manage their honey bee colonies in ways that optimize colony health. Disentangling the impact of management from other variables affecting colony health is complicated by the diversity of practices used and difficulties handling typically complex and incomplete observational datasets. We propose a method to 1) Varroa mite population Control by several methods , and 2) Many nursing bee put in hive before wintering.

This study investigated ethopabate (EPB) residues in edible tissues of broiler chickens given in drinking water and established the withdrawal time (WT) of EPB in poultry tissues. Twenty-four healthy Ross broiler chickens were orally administered with EPB at the concentration of 3.8 mg/L for 14 days (EPB-1, n=24) and 15.2 mg/L for 7 days (EPB-2, n=24) through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3, and 5 days, respectively. EPB residue concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient values ranged from 0.9980 to 0.9998, and the limits of detection and quantification (LOQ) were 0.03~0.09 and 0.1~0.3 μg/kg, respectively. Mean recoveries in muscle, liver, kidney and skin/fat tissues were 95.9~109.8, 108.7~115.3, 89.9~96.6 and 86.7~96.8%, respectively, and coefficient of variations were less than 17.11%. At the end of the drug-administration period (0 day), EPB was detected at levels under the LOQ in all tissues from both the EPB-1 and EPB-2 groups. According to the results of EPB residue in Ross broiler tissues, withdrawal periods of both EPB-1 and EPB-2 in poultry tissues were established to 0 day. In conclusion, the developed analytical method is suitable for the detection of EPB in poultry tissues, and the estimated WT of EPB in poultry tissues will contribute to ensuring the safety of Ross broiler chickens.

From 2020, Korean Animal and Plant Quarantine Agency has reset the withdrawal time (WT) for veterinary drugs typically used in livestock in preparation for the introduction of positive list system (PLS) program in 2024. This study was conducted to reset the MRL for amprolium (APL) in broiler chickens as a part of PLS program introduction. Forty-eight healthy Ross broiler chickens were orally administered with APL at the concentration of 60 mg/L (APL-1, n=24) for 14 days and 240 mg/L (APL-2, n=24) for 7 days through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3 and 5 days, respectively. Residual APL concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient (0.99 >), the limits quantification (LOQ, 0.3~5.0 μg/kg), recoveries (81.5~112.4%), and coefficient of variations (<15.5%) were satisfied the validation criteria of Korean Ministry of Food and Drug Safety. In APL-1, APL in all tissues except for kidney was detected less than LOQ at 3 days after drug treatment. In APL-2, APL in liver and kidney was detected more than LOQ at 5 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal periods of APL-1 and APL-2 in poultry tissues were established to 3 and 2 days, respectively. In conclusion, the developed analytical method is sensitive and reliable for detecting APL in poultry tissues. The estimated WT of APL in poultry tissues is longer than the current WT recommendation of 2 days for APL in broiler chickens.

To be better fit for highways, pavement systems are required to provide comfortable and safe driving and be structurally durable. Composite pavements can be an effective option as they are more durable by placing a high functional asphalt overlay on a rigid concrete base layer. In order to apply a composite pavement system to the field, it is necessary not only to develop technologies that prevent reflecting crack and deterioration of the base layer, but also to improve bonding performance of materials and ensure structural performance as a pavement system against traffic loading. In advanced countries like Japan, USA and Europe, high-functional composite pavement systems are being put into practice across new highway networks. In this study, we evaluated structural performance (rutting, reflecting crack, and deflection) by applying traffic loads of actual highways through an accelerated pavement tester (APT) of a composite pavement section made up of a quiet porous surface laid over a water-proofing layer, a continuously reinforced concrete base, and a lean concrete sub-base layer, which was developed with new pavement methods used for each layer prior to field application. The APT specimen was constructed with paving materials and equipment actually used on site in the same dimensions (W3.5m*L14m*H2m) as actual highway sections in Korea, and 3-axle double-wheel heavy load (45ton) cart type KALES(Korean Accelerated Loading and Environmental Simulator) traveling on the specimen in both directions was used to simulate traffic loading. After applying around 8,574,000 ESALs of traffic loads, no reflecting crack occurred on the asphalt surface of the composite pavement, without surface distress except for rutting. In order to examine what causes rutting of pavements, we surveyed thickness of pavements by layer and measured asphalt density.

전국식물기생선충 분포조사기간에 채집된 선충중에서 Dorylaimida 목, Trichodoroidea 상과의 Trichodoridae 과선중이 분류동정되었다. Trichodorus cedarus는 콩, 배추, 보리 및 사과등에서 채집되어 분류동정되었으며, Paratrichodorus porosus 콩, 마늘, 배추 및 옥수수 등에서 검출되었다. Trichodoroidea 상과의 선충은 아직까지 우리나라에 기록되지 않았었다.