This study is done to evaluate a dry sterilization method of plant pathogens on the citrus during storage. Cold plasma technique based on dielectric barrier discharge (DBD) technology was used for plasma actuating. Citrus was stored both cold (5℃, 90%RH) and ambient (18℃, 50%RH) store and analyzed for 3 weeks. Treatment (N=24) and control samples (N=48) were randomly divided for each group. The specification of the DBD plasma actuator is as follows: input voltage is 130 V, current is 0.3 A, flow rate is 15L/min, actuator operation time is 5 seconds (ON), and break time is 30 minutes (OFF). Concentration of ozone was 1.0~3.7 ppm and nitrogen dioxide was 0.5~2.5 ppm. Sterilized air was circularized by a diaphragm pump through a transparent Teflon pipe connected to the chamber and the actuator. Every 3~4 days, the selected samples were rinsed and then inoculated with potato dextrose agar (PDA) for 5 days. Cell number was counted by hemocytometer. Physical properties such as weight, color, soluble solid contents (SSC) and rigidity of peel were measured and compared during storage. Color and rigidity was measured four spots through equator of fruits.

Eighty kinds of pesticides registered in the peach and leaf perilla were assessed the efficacy against the 4th nymph stage of citrus flatid planthopper. Plant of Sharon, host plant preferred by citrus flatid planthopper, was cut from 5 to 7 cm and dipped 10 seconds into recommended concentrations of pesticides, respectively, and then dried naturally for the 30 minutes. New shoot of Plant of sharon treated pesticides and 10 to 15 final nymphs of citrus flatid planthopper put together in the 50㎖ tube and the number of live nymphs was investigated after 48 hours. Pesticides showing mortality over 90% were seven, namely, bifenthrin EW, Rhamda-cyhalothrin EC, Clothianidin SC, Benfuracarb SG, Chloropyrifos WP, Bifenthrin+methoxypenozide SC, Chloropyrifos+imidacloprid WP. When the forest surrounding the peach and leaf perilla was occurred and damaged by citrus flatid planthopper, the use of these pesticides is judged to be effective in the control of this pest.

본 연구는 감귤의 해충인 귤굴나방의 기생성 천적의 종류와 기생률을 조사하기 위하여 수행하였다. 2013～2014 제주 감귤원에서 발견된 귤굴나방 기생봉 천적은 좀벌상과에 속한 총 7종이 발견되었다. 그 중 좀벌과에 속한 Sympiesis striatipes가 73%, Quadrastichus sp.가 22%로 대부분을 점유하였다. 나머지 종은 Neochrysocharis sp., Ageniaspis sp., Pnigalio sp., Holcopelte sp., Trichomalopsis sp.(Pteromalidae) 등이었다. 천적의 평균 기생률은 관행재배에서 10.7%, 무농약 과원에서는 32.2%를 나타냈다.

Mediterranean fruit fly, Ceratitis capitata, is one of the most important quarantine pest worldwide. Fruit flies cause serious damage on orchard, and also can cause quarantine problem to fruit exportation. Recently, because of global warming, there is threats of fruit fly invasion to Korea, especially to Jeju island. So there should be a anticipative research about fruit fly control. Many physical quarantine treatment methods, like heat treatment and low-temperature treatment, are developed to control quarantine pests. Recent researches indicate that low-temperature treatment shows good efficacy on several quarantine pests without phytotoxicity. In this trial, we’ve applied the low-temperature treatment on citrus at laboratory and pilot scale containers to validate efficacy and phytotoxicity. Egg and larvae stage of C. capitata was completely controlled after 5 days and 8 days low-temperature treatment at 0℃ respectively, and there was no phytotoxicity on citrus. These results indicate that the low-temperature treatment can be applied to control fruit fly on citrus fruit.

The citrus leaf miner (CLM) is an important citrus pest. A thorough understanding of the biology and population dynamics of CLM are essential for development of reliable pest population prediction system. We investigated the developmental periods of the species under ten constant temperature schemes (12.5℃~39℃). Furthermore, we established a development model of CLM, based on the result of a laboratory experiment. The immature developmental duration of CLM at constant temperatures were 63.5 days at 15℃, 23.9 days at 21℃, 15.6 days at 27℃, and 12.3 days at 33℃, showing statistically significant difference among temperature regimes. The lower threshold temperature and thermal constant were 11.3℃ and 243.7 DD, respectively, for immature development. In relation to temperature, non-linear development models were established for each developmental stage of CLM.

The citrus leaf miner (CLM) is a of important citrus pests in Jeju island, but it’s not clear about ecology of over-wintering in Jeju. We investigated the developmental stage to know how the CLM overwinters in 20 sites. And we investigated the mortality of larvae, pupae and adult stage of CLM in open citrus cultivated field December, 2017 to April 2018 and growth chamber conditions(from –10 to 5 ℃). As a result, no larvae and adult survived open field during winter. We concluded that the CLM usually overwinters as pupa during winter.

Citrus fruit is important source of flavonoids, mainly flavanones which are narirutin and hesperidin. Those citrus flavonoids have been found to have health-related properties including antioxidant, anticancer, and anti-inflammatory. The main purpose of this study was to verify that the extraction of narirutin and hesperidin from Citrus peel can be more effective by combining pulsed electric field (PEF) pre-treatment and subcritical water extraction (SWE). Citrus unshiu peels were treated with PEF under conditions of electric field strength (3 kV/cm) and times (1 and 2 min). Subsequent SWE was conducted by using a Dionex Accelerated Solvent Extractor (ASE, Model 350) at extraction temperature 170°C for 10 min. The total flavonoids content was measured by using the aluminum chloride colorimetric method and the antioxidant capacity was analyzed by the Ferric reducing antioxidant power (FRAP) assay using spectrophotometer. The concentrations of narirutin and hesperidin were increased as PEF pre-treatment time increased. The highest concentrations of narirutin and hesperidin were 13.41 mg narirutin/g dry citrus peel and 141.16 mg hesperidin/g dry citrus peel at PEF pre-treatment condition of 3 kV/cm and 2 min. The total flavonoids contents of the extracts increased 105.2% and 123.1% for citrus peel PEF treated at 1 and 2 min, respectively. In addition, compared to the untreated sample, PEF pre-treatments of 1 and 2 min increased the antioxidant capacity of the extracts 109.2% and 160.8%, respectively. Therefore, the results demonstrate the potential of PEF pre-treatment to improve the SWE of flavonoids from citrus unshiu peel.

본 연구에서는 건조된 유자씨박 70% 에탄올 추출물 및 에틸아세테이트 분획물을 제조하고, 이들의 항산화능을 평가하였다. 유자씨박 추출물 및 분획물의 수율은 각각 5.1 및 0.9%로 나타났다. 1,1-Phenyl-2-picrylhydrazyl (DPPH) 라디칼 시험법에서 자유 라디칼 소거 활성(FSC50)은 70% 에탄올 추출물과 에틸아세테이트 분획물이 각각 512.1 및 514.0 μg/mL를 나타냈다. 라디칼 소거활성은 (+)- α-tocopherol(9.0 μg/mL)보다는 비교적 낮았다. Fe3+-EDTA계를 이용한 총 항산화능 평가에서 유자 씨박 70% 에탄올 추출물 및 에틸아세테이트 분획의 OSC50은 242.9 및 86.5 μg/mL이었다. 유자씨박 에틸아세테이트 분획은 70% 에탄올 추출물 보다 높은 총 항산화능을 보였지만, 대조군인 L-ascorbic acid (1.7 μg/mL)보다 낮게 나타났다. 1O2로 유도된 세포 손상에 대한 보호 효과(τ50)에서, 70% 에탄 올 추출물은 5, 10, 25, 50 μg/mL 에서 농도 의존적인 세포 보호 효과를 보였다. 유자씨박 에틸아세테 이트 분획은 5 μg/mL 에서 39.8 min으로 (+)-α-tocopherol (36.1 min)과 유사한 세포 보호 활성을 나타났다. 그러나 10 μg/mL 이상에서 농도가 증가함에 따라 낮은 세포 보호 효과를 나타냈다. 결과적 으로, 유자씨박 에틸아세테이트 분획물이 라디칼 소거활성이 아닌 총 항산화 활성을 통해 낮은 농도에서 는 세포 보호 효과를 나타냈으나 높은 농도에서는 세포 보호 효과가 농도 의존적으로 나타나지 않았다.

Recently, fruit vinegar made from fruit wine has been famous due to its health function and nutrition. Therefore, there are many fruit vinegar products manufactured by major big food companies and small company as well as one person through the internet shopping mall. In this study, 4 type citrus fruits vinegar (grapefruit, tangerine, orange, lemon) were investigated to find out the quality of vinegar for consumers’ wise selection. Commercial vinegar which are commonly produced by fermenting mixture of brown rice vinegar with fruit extracts were analyzed that sugar content, pH, acidity, turbidity, DPPH assay, FRAP assay, TPC and manufacture method. Among all samples, 4 tangerine vinegar acidity were suit with standard quality (4~29%) by MFDS. pH scale of all vinegar was from 2.76 to 3.48 and lemon vinegar was lowest. Average sugar content (brix%) was lowest at tangerine vinegar as 17.4. In the DPPH radical scavenging activity, there was no significant difference at all samples. In the TPC study and FRAP assay, lemon vinegar showed the highest value, while grapefruit, tangerine, and orange vinegar were not significantly different. From the result, product type, and qualities and suitability as vinegar product of various citrus fruits vinegar were observed and it was found that although product name is ‘vinegar’, some vinegar products were not suit with standard quality (acidity%).

Spathius exarator의 종 그룹에 속하는 S. ibarakius Belokobylskij et Maeto가 한반도에서 알락하늘소(Anoplophora chinensis)의 1령과 2령 유충에 외부기생하는 것으로 확인되었다. 산란유인목을 이용하여 유리알락하늘소와 알락하늘소의 기생봉을 탐색하는 과정에서 이 고치벌이 발견 되었다. 이 고치벌의 진단형질과 수컷의 특징, 삽화 및 한반도에 분포하는 종들의 기주목록을 함께 제공하였다.

이 논문은 비모수적 자료포락분석 기법을 이용하여 감귤농가의 경영효율성을 추정하였다. 추가적으로 커널밀도함수를 이용하여 경영효율성의 분포가 지난 13년간 어떻게 바뀌었는지도 도식화하였다. 연구를 위해 농촌진흥청에서 조사 발표하는 자료를 사용하였다. 분석결과를 보면, 지난 13년간 경영효율성은 시설 감귤농가와 노지 감귤농가 모두에서 상승하는 것으로 나타났다. 이것은 수입농산물이 증가하는 상 황 하에서 감귤농가의 경영효율성이 개선되고 있음을 의미한다. 경영효율성을 순수기술적 효율성과 규 모 효율성으로 분해한 결과, 순수기술적 효율성은 점차 개선되는 반면에 규모 효율성은 악화되는 것으 로 분석되었다. 하지만 여전히 효율성 개선의 여지는 순수기술적 효율성 측면에 있는 것으로 분석되었 다. 순수기술적 효율성은 꾸준히 계속 향상시키되 적정규모를 찾아가는 노력도 병행해야 할 것으로 보 인다.

This study was conducted to investigate the seasonal occurrence of Phyllocnistis citrella Stainton (Citrus leafminer; CLM) and parasitoids in Jeju region, where the damage of CLM to the citrus farm has been recently increased. For this study, annual CLM mornitoring using sex pheromone traps were conducted in the citrus farm of Jeju from 2011 to 2015. The mean annual occurrence of CLS was 477,389 and appeared to increase along the temperature.

The Citrus Leafminer (CLM) larvae creates shallow tunnels in leaves of citrus (orange, mandarins, lemons, grapefruit, etc) and commonly attacks citrus young leaves. They spread almost worldwide (North America, Asia, Australia, etc) and difficult to control by chemicals due to their small size and their behavior of leaf rolling. Due to difficult of managing, our interest is preparing pheromone to control; Z7Z11-16;Al is known as the sex pheromone of this species in Japan. While blending Z7Z11-16;Al and Z7Z11E13-16;Al (3:1 ratio) is known as the pheromone of this insect in North America. Even though commercialized and mass produced already in overseas, there had been almost no report in Korea about synthetic studies and field screening results. The control of the regio-isomers is very important in this kind of pheromone synthesis. Our strategy is the regio-selective Wittig olefination reaction between E-pent-2-enyl(triphenylphsphonium)bromide (phosphonium salt) and the counterpart aldehyde using sodium hexamethyldisilazide (NaHMDS) as a base. All the spectroscopic data (1H, 13C, GC-Mass, etc) are nicely matched with the previously reported values. The field screening in the Jeju island is currently ongoing and will be reported.

목화진딧물(Aphis gossypii Glover) (Hemiptera: Aphididae)은 감귤에서 그을음병을 유발하여 감귤 과실에 경제적으로 피해를 주는 해충이다. 본 연구는 무가온 하우스 감귤에서 계절초기 목화진딧물이 어떠한 경로를 거쳐서 감귤나무에 정착하는지 구명하기 위하여 수행하였다. 감귤나무에서 진딧물 월동알 조사결과 가을순이 난 여름순에서 많이 발견되었는데 월동알은 대부분 조팝나무진딧물이었으며, 목화진딧물 월동알은 발견되지 않았다. 봄순에 정착하는 목화진딧물 유시형 성충은 크게 4월 하순(조기비산)과 5월 하순(지연비산)에 두 차례 관측되었다. 지연비산은 완전생활형 간모세대에서 유시형이 출현하는 시기와 일치하였다. 조기비산 시기에 황색수반트랩에서도 목화진딧물 유시형 성충이 유살되었는데 확실하지는 않으나 월동잡초에서 잔존하고 있던 불완전세대 개체군으로 추정되었다. 결과적으로 무가온 하우스 감귤에서 목화진딧물의 정착은 불완전생활형의 조기비산과 완전생활형의 지연비산으로 일어난다는 것이 확인되었다.

Jeju citrus, which contains an abundance of calcium and vitamin, was used to develop fermented citrus peel extract. A total of seven probiotic strains were applied to tangerine dermis to select the best growing bacteria in citrus peel extracts. B. longum, B. bifidum, and L. mesenteroides were found to grow best in citrus peel extract culture containing glucose, yeast extracts, peptone, and potassium phosphate. Citrus peel extract culture consisting of 1% yeast extract, 5% peptone, and 0.1% phosphate was the best environment for growth of probiotics. The pH, acidity, and viable cell numbers of these fermented extracts were measured. The initial pH level of fermented extracts with nutrients was 5.25 and dropped rapidly to 3.39 after 72 hours of fermentation. The acidity of fermented extracts increased to 4.08 % after 72 hours of fermentation, and the viable cell number in fermented extracts after refrigeration for 2 weeks was 1.3×1010 CFU/mL. The antimicrobial activity of citrus peel fermented extracts against Campylobacter jejuni was determined, and concentrations more than 25,000 ppm showed antimicrobial activity.

주스의 품질악화를 초래하는 효소를 불활성화시키기 위해서 감귤 주스와 사과 주스 추출물에 초고압 처리와 열처리를 하여 각 시료의 PPO와 POD의 불활성화 정도를 확인하고 동역학 모델에 적용하여 이들의 불활성화 특성을 연구하였다. 감귤 주스와 사과 주스에서 모두 PPO가 POD보다 열과 압력에 대해서 상대적으로 내성을 갖는 것을 알 수 있었으며, 초고압 처리 과정을 거쳤을 때 보다는 열처리 과정을 거쳤을 때 PPO와 POD가 효과적으로 불활성화되는 것을 확인할 수 있었다. 초고압 기술은 처리 후에도 제품의 영양분과 색의 변화에 영향을 미치지 않기에, 최상의 상태와 품질로 제품을 제공 할 수 있는 장점을 가지고 있지만, 효소를 불활성시키기에는 부족하다는 단점을 가지고 있다. 이를 보완하여 산업적으로 이용되어지기 위해서는 영양분이 파괴되지 않는 열 처리 조건을 잡고, 효소를 효과적으로 불활성시킬 수 있는 초고압 처리 조건과 결합하여 최상의 결과를 얻을 수 있는 조건을 찾는 연구가 필요하다고 판단된다.

The purpose of this study is to develop a growth prediction model that can predict growth and development information influencing the production of citrus fruits: the growth model algorithm that can predict floral leaf ratio, number of fruit sets, fruit width, and overweight depending on the main period of growth and development with consideration of the applied weather factors. Every year, large scale of manpower was mobilized to investigate the production of outdoor-grown citrus fruits, but it was limited to recycling the data without an observation supporting system to systemize the database. This study intends to create a systematical database based on the basic data obtained through the observation supporting system in application of an algorithm according to the accumulated long term data and prepare a base for its continuous improvement and development. The importance of the observed data is increasingly recognized every year, and the citrus fruit observation supporting system is important for utilizing an effective policy and decision making according to various applications and analysis results through an interconnection and an integration of the investigated statistical data. The citrus fruit is a representative crop having a great ripple effect in Jeju agriculture. An early prediction of the growth and development information influencing the production of citrus fruits may be helpful for decision making in supply and demand control of agricultural products.