• Title, Summary, Keyword: Yuzu(Citrus junos)

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Verifications of Resistance to Phytophthora spp. in 2-year-old Citrus junos Cultivars and Related Specie

  • Kwack, Yong-Bum;Kim, Hong Lim;Kwak, Youn-Sig;Lee, Yong Bok
    • Korean Journal of Soil Science and Fertilizer
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    • v.51 no.1
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    • pp.28-34
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    • 2018
  • Yuzu (Citrus junos) gummosis disease, caused by Phytophthora nicotianae, was first reported in 1997. As known in citrus, Phytophthora is the most fastidious soil-borne pathogen to control. In order to minimize its damage to Citrus spp., integrated pest management (IPM) approach, including fungicide chemicals and resistant cultivars, is necessary. Therefore, in this study we tried to evaluate tolerance of yuzu cultivars and its related species against yuzu Phytophthora. Trifoliate orange was evaluated as a susceptible host to yuzu Phytophthora by both mycelial growth onto extract media and immature fruit inoculation. However, in zoospores spray-inoculation on 2-year-old cuttings tree, trifoliate orange appeared to have a resistant property as showing less than 6% diseased leaf rate. Among yuzu cultivars only 'Namhae No. 1' appeared resistant property against both P. nicotianae and P. citrophthora. The 'Namhae No. 1' showed 5.7% and 10.6% diseased leaf ratio by P. nicotianae and P. citrophthora, respectively. Clearly, in order to reduce damages caused by two yuzu Phytophthora, we suggest that growers may utilize a trifoliate orange as a rootstock and 'Namhae No. 1' as a scion for fruit production.

Physicochemical and Sensory Properties of Yuzu(Citrus junos) Treated with Enzyme Complex for Removing Bitter Substance (고미성분 제거를 위한 복합효소처리 후 유자의 이화학적 및 관능적 특성)

  • 김용두;김경제
    • Korean Journal of Food Preservation
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    • v.11 no.1
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    • pp.38-41
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    • 2004
  • To obtain basic data for utilizing Yuzu(Citrus junos) as row materials to industrial products, enzyme treatments conditions for removing bitter substances was investigated. The amount of nuringin and hesperidin weve 61.94 and 9.98 mg% in Yuzu juice. When 3% Amorepacific enzyme and Japanese naringinase were treated with the juice for 120 minutes, naringin and hesperidin were decreased to 6.85 and 1.11 mg% ; 8.43 and 0.06 mg%, respectively. The changes in Hunter color value of the juice were negligible by enzyme treatments. However, the redness was increased and lightness was decreased by the enzymes. When Yuzu-juice was treated with the enzymes, sensory scores were increased. The optimum amount of Amorepacific for reducing bitter taste was determined to 3%.

The Status of Spot Damage and Fruit Piercing Pests on Yuzu (Citrus Junos) Fruit (유자과실의 반점피해 상황과 흡즙해충의 종류에 관하여)

  • 최덕수;김규진;임근철
    • Korean journal of applied entomology
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    • v.39 no.4
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    • pp.259-266
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    • 2000
  • This study was carried out to investigate the status of spot damage by fruit piercing pests and the kinds of these pests on yuzu (Citrus junos) fruit in Koheung, the most chief producing district of yuzu fruit in Korea, from ’97 to ’99. The extent of spot damage by fruit piercing pests on yuzu was increasing in recent years. This damage of fruits was severe in the lower canopy than the high one from ground and intercropping groves between yuzu trees had a greater damage to compare with single cropping of yuzu. Spot damage of yuzu fruit was occurred mainly from late September to early November when yuzu fruit is enlarging and coloring yellow. The blackish concave spot on yuzu fruit surface was appeared in 3 days after introduction of Riptortus clavatus into a netted cage containing one yuzu fruit and the diameters of this spot was 8.3 mm. At 10 days after introduction, this spot changed into milky-white with 9.2 mm diameters. One concave spot has contained oil cells by 17.7 and its external appearances has unchanged until harvest. The kinds of piercing pests of yuzu fruit were investigated with 3 orders, 16 families and 37 species. These pests were classified by 11 species of bugs, 5 species of hoppers and 21 species of moths. Among them, dominant species were Physopelta gutta, Halyamorpha halys, Empoasca vitis, Aedia leucomelas, Agrotis tokionis, etc. Macroglossum bombylans and Acherontia s쇼x are newly confirmed species as the fruit piercing moths in Korea.

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Population Fluctuation, Developmental Character of Panonychus citri and Damage Degree as its Control Density on Young Yuzu (Citrus junos) (유자에서 귤응애의 발생소장, 온도별 발육특성 및 방제밀도별 피해정도)

  • 최덕수;김규진
    • Korean journal of applied entomology
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    • v.37 no.2
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    • pp.193-198
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    • 1998
  • Experiments were conducted to investigate the population fluctuation, developmental periods, fecundity, hatching rate and demage of Citrus red mite (Panonychus citri M.) on Yuzu trees (citrus junos T.) from 1996 to 1997. Citrus red mite occurred from May to November and made two peaks. The first peak was in July to August and the secondary peak was in October. Density of the second peak was higher (9.5 miteslleaf) than that of the first peak. In the constitution rate of each developmental stage of citrus red mite on Yuzu leaves, egg stage occupied 85%. At the four constant temperature (15, 20, 25, 30 + 1$^{\circ}$C, RH 60 + lo%, 14L- IOD) conditions, the developmental period from egg to adult was 41 .l, 15.5, 11.0 and 9.4 days ; Mean longevity of adult was 23.3, 8.3, 6.3, and 6.1 days; Mean number of egg laid per female per day was 1.6, 3.2, 4.5, 4.0 eggs; Mean hatching rate was 66.6, 85.7, 90.7 and 94.7% at above temperature, respectively. When sprayed acaricide at different density of Citrus red mite, the growth of young Yuzu tree were better at low density. Defoliation rate during winter was 13.5, 20.6, 53.1, 72.6% at 4 control density 1 , 3, 6 mites per leaf and uncontrolled (10 ( ). When every time spray acaricide under 3 mites per leaf, defoliation rate during winter suppressed above 50% compare to uncontrol 72.6%.

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Selection and Control Effect of Environmental Friendly Organic Materials for Controlling The Main Disease of Yuzu (Citrus junos Sieb) (유자에 발생하는 주요 병해 방제를 위한 유기농업자재 선발 및 방제효과)

  • Park, Jee-Sung;Cho, Woong-Jun;Kim, Woo-Sik
    • Korean Journal of Organic Agriculture
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    • v.22 no.1
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    • pp.115-127
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    • 2014
  • This study was conducted to select environmental friendly organic materials for controlling the main disease of Yuzu (Citrus junos Sieb). Meloanose caused by Phomopsi scitri and Scab caused by Elsinoe fawettii are the most common disease in Yuzu. In this study, of which Meloanose disease severity was severe at late of June corresponded with high humidity due to frequent rainfall at that time. In addition, occurrence of two disease have shown in old tree than young. After processing with environmental friendly organic materials, reduction of disease severity was 51~73% and 41~75% in case of Meloanose and scab, respectively. Based on result, environmental friendly organic materials tested in this study may source for controlling both Meloanose and scab diseases on Yuzu.

Characterization of the host reaction of some citrus plants with Xanthomonas axonopodis pv. citri, causing citrus bacterial canker disease.

  • Myung, Inn-Shik;Hyun, Jae-Wook;Kim, Kwang-Sik;Lee, Sung-Chan;Lim, Han-Chul
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • pp.120.3-121
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    • 2003
  • Relative degree of resistance of citrus to Xanthomonas axonopodis pv. citri, the causal bacterium of canker, was investigated. Growth rate of a bacterium in leaf tissues after infiltration, disease incidence, and percent of lesion area were compared. By using growth rate[(GR=(At - A$\sub$t-1/)/A$\sub$t-1] host plants were differentiated into susceptible and resistant. Growth rates reached to peak at 40 hrs after inoculation and then declined. The growth rate in leaf tissues of a moderately susceptible cultivar, Citrus sinensis vu. Lane late(sweet orange), was the highest, and those of C. unshiu ${\times}$ C. sinensis(kiyomi), C. junos(yuzu), [(Citrus. unshiu x C. sinensis) x C. reticulata] (shiranuhi), and C. unshiu(satuma mandarin) were similar. This result indicates that the growth rate of the bacterium in leaf tissues can be effectively used for evaluation of disease resistance for citrus plants to X. axonopodis pv. citri. The disease on sweet orange occurred earlier than relatively resistant citrus plants tested. The percent of lesion area on leaf was also higher in sweet orange than those of satsuma mandarin, shiranuhi and kiyomi, and yuzu. The disease severity was highest on sweet orange and followed by kiyomi, shiranuhi, satsuma mandarin, and yuzu.

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Optimum Condition for Removing Bitter Substance of Yuzu(Citrus junos) by Enzyme Treatment (효소처리에 의한 유자 고미성분 제거의 최적 조건 연구)

  • 김용두;김경제
    • Korean Journal of Food Preservation
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    • v.11 no.1
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    • pp.53-56
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    • 2004
  • The content of naringin and hesperidin of Yuzu were 95.54 and 103.99 in peel ; 65.77 and 77.18 in flesh ; 16.49 and 15.88mg% in seed, respectively. When 10 mg% of naringin and 5 mg% hesperidin were treated with 10.0 units naringinase and 2.0 units of hesperidinase, they were decreased to 0.11 and 0.45 mg%, respectively. One percent of Japanese naringinase digested naringin and hesperidin that their final concentration were 0.54 and 0.09 mg% in 30 minutes, while 5% Amorepacific enzyme did until 0.26 and 0.04 mg%, respectively.

RT-PCR Detection of Citrus Tristeza Virus form Early Satsuma Nandarin and Yuzu in Cheju Island

  • Kim, Daehyun;Jaewook Hyun;Hyunsik Hwang;Lee, Sukchan
    • The Plant Pathology Journal
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    • v.16 no.1
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    • pp.48-51
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    • 2000
  • Citrus tristeza virus (CTV) was identified form CTV-infected early satsuma mandarin (Citus unshiu) and yuzu (C.junos) by RT-PCR. The total RNAs were isolated from citrus bark and seaf tissues infected with CTV and reverse transcription was followed with primers designed for amplifying CTV coat protein gene. DNA fragments 738 bp were amplified by RT-PCR and these products were colned for sequence analysis. Based on the sequence analysis, this PCR product has 97% sequence homology to CTV (T-385) CP gene isolated from USA. RT-PCR assay for CTV detection was more sensitivity than ELISA assay which was done with anti-CTV CP antibody. This is the frist report about CTV identification in Cheju island Korea.

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Physiological Study for Dense Planting and Early High Yielding Potential of New Korean Dwarf Yuzu (Citrus junos Sieb. Ex Tanaka) (신육성 왜성 한국유자 (Citrus junos)의 밀식재배 및 조기 다수확을 위한 생리적 연구)

  • 송원섭
    • Korean Journal of Plant Resources
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    • v.8 no.3
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    • pp.265-274
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    • 1995
  • Characteristics of vegetative spur leaf, spur bud, fruiting supr leaf and flowering in relation to canopy position was investigated on order to promote better spur bud and flower bud differentiation on Citrus junos. There was no difference in vegetative spur leaf characteristics among directions. Vegetative spur leaf number and leaf area showed no difference between top and bottom position. There was no difference in spur bud size among directions, but spur bud at top was larger than that at bottom. Specific leaf weight of vegetative spur was mostly influenced by light interception, and leaf dry weight per spur average leaf dry weight, spur bud length and diameter had also a very high correlation with light interception rate. Shading and GA treatment in spur bud and flower bud differentiation was ineffective than natural light. Fruit thinning enhanced fruit quality as well as flower bud differentiation through an increase of leaf number per fruit, over 40 in Citrus junos.

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Control Methods of Spot Damage by Fruit Sucking Pests on Yuzu (Citrus junos) fruit (유자과실의 흡즙충류에 의한 반점피해 방제에 관하여)

  • 최덕수;김은식;김동관;김규진
    • Korean journal of applied entomology
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    • v.40 no.1
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    • pp.77-82
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    • 2001
  • Flying behavior during nighttime and control methods of fruit sucking pests were investigated in yuzu (Citrus junos) groves at Koheung area from August to November in 1999. Among the 3 kind of bulbs with different color (white, blue and yellow), white bulb attracted the most number of fruit sucking pests . The 93 percent of the moths was attracted from sunset to 24 o\`clock. Main flying time of hemipteriods in early, mid, and late October were from 22 to 04 o\`clock, sunset to 02 o\`clock and sunset to 24 o\`clock, respectively. Their flying time become earlier as the night temperature declines. For control of fruit sucking pests, attraction liquid traps, light traps (100 W) and illumination light bulb were set up in the yuzu groves (1,000 $\m^2$) from the 1 st October to the 3rd November. Attraction liquid was composed of a raw rice wine 2,000 ml+black sugar 100 g+vinegar 100 ml. When established at 3 sites per 1,000 $\m^2$ orchard, attraction liquid trap reduced the number of sucking spots on yuzu fruit to 64% and its attracting effect maintained for 3 weeks after setting-up. Three light traps per 1,000 m2 which turned on from sunset to 02 o\`clock reduced the number of sucking spots by 60% .

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