• Korean journal of applied entomology
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• v.58 no.3
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• pp.175-182
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• 2019

The citrus leafminer, Phyllocnistis citrella (Lepidoptera: Gracillaridae), is an important pest that decreases the productivity of citrus trees by attacking citrus leaves, and especially it causes a severe damage during the young growth stage. In this study, we investigated the distribution of eggs on the leaves of shoots according to the position and the survival rate of this pest in the field condition. The occurrence patterns of P. citrella eggs in citrus orchards were largely affected by the occurrence of shoots. Even if the adults were still being attracted in the pheromone traps, the eggs were not observed on leaves when the growth of shoots was stopped. The density of P. citrella eggs in the citrus shoots peaked at the fifth or sixth leaf from the terminal leaf, and over 90% of the eggs were found in the first to eighth leaves as a whole. In 2015 and 2016, the average survival rate of larvae surviving to pupa was 1.4%, and the rate of survival to adults was 0.2%, indicating that most of them died. Furthermore, we have discussed the management strategy of P. citrella considering the distribution of eggs and the larval survival rate in the citrus shoots.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.419-427
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• 2013

The insecticidal activity of 124 plant essential oils and control efficacy of six experimental spray formulations (SF) containing 0.25, 0.5, 1, 2.5, 5, and 10% of the selected oils was examined against both nymph and adult of the citrus flatid planthopper, Metcalfa pruinosa using direct contact applications (leaf dipping and spray). Reponses varied according to dose (1,000 and 500 mg/L). When exposed at 1,000 mg/L for 24 h using leaf dipping assay, 19 essential oils showed strong mortality (100%) among 124 essential oils screened. At 500 mg/L, 100% mortality was observed in cinnamon technical, cinnamon green leaf, cinnamon #500, cassia tree, citronella java and pennyroyal followed by origanum, thyme white, grapefruit, savory, fennel sweet, aniseed and cinnamon bark showed considerable mortality (93.3-80%) against nymphs of M. pruinosa. The moderate mortality (73.3-60%) was found in thyme red, tagetes, calamus, lemoneucalptus and geranium. Oils applied as SF-10% sprays provided 100 % mortality against adult M. pruinosa. One hundred mortalities were achieved in cinnamon technical at >SF-0.5 formulation, in cinnamon #500, cinnamon green leaf and penny royal at >SF-2.5. To reduce the level of highly toxic synthetic insecticides in the agricultural environment, the active essential oils as potential larvicides could be provided as an alternative to control M. pruinosa populations.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.68.2-69
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• 2003

Genetic transformation carried out to induce the pathogenicity mutants from the two isolates, Elsinoe fawcettii R-34 and MUD of citrus scab fungus to hygromycin resistant by transferring plasmides (pUCATPH) that contain hygB gene. We produced protoplast for transformation by using of combinations of available enzymes including ${\beta}$-D-glucanase, ${\beta}$ -glucuronidase, Iyticase and driselase. The protoplasts regenerated at 64 $\mu\textrm{g}$/ml of hygromycin B but not 128 $\mu\textrm{g}$ in sensitivity test to identify the concentration of useful marker for the selection of transformants. Approximately 1200 and 67 hygromycin resistant isolates from strain R-34 and strain MUD, respectively, were isolated on PDA added with 200 $\mu\textrm{g}$ /ml of hygromycun B. Fifty seven and 4 of hygromycin resistant isolates from strain R-34 and MUD, respectively, did not produce necrotic lesions on the leaf in detached-leaf assay. Finally, 9 isolates were isolated from strain R-34, and these Isolates produced non or very few symptoms on seedlings of citrus in greenhouse pathogenicity test. And it's very interesting that some isolates produced melanose-like symptom on very young leaves which it was not typical symptom and somtimes produced on only expanded leaf.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.295-308
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• 2016

This study investigated the effects of a flavonoid-rich ethanol extract of persimmon leaf (PL), an ethanol extract of Citrus junos Sieb (CJS), and a PL-CJS mixture (MPC) on mice fed a high-fat diet (HFD). We sought to elucidate the mechanisms of biological activity of these substances using measurements of blood coagulation indices and lipid metabolism parameters. C57BL/6J mice were fed a HFD with PL (0.5% (w/w)), CJS (0.1% (w/w)), or MPC (PL 0.5%, CJS 0.1% (w/w)) for 10 weeks. In comparison with data obtained for mice in the untreated HFD group, consumption of MPC remarkably prolonged the activated partial thromboplastin time (aPTT) and prothrombin time (PT), whereas exposure to PL prolonged aPTT only. Lower levels of plasma total cholesterol, hepatic cholesterol, and erythrocyte thiobarbituric acid-reactive substances, hepatic HMG-CoA reductase, and decreased SREBP-1c gene expression were observed in mice that received PL and MPC supplements compared with the respective values detected in the untreated HFD animals. Our results indicate that PL and MPC may have beneficial effects on blood circulation and lipid metabolism in obese mice.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.3
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• pp.159-169
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• 2023

Purpose : Though other Citrus spp. have reported their anti-inflammatory and antioxidative activities in previous studies, the biological activity of Kiyomi (Citrus unshiu × C. sinensis) has not been reported yet. Therefore, this study attempted to analyze the anti-inflammatory mechanisms of Kiyomi leaf ethanol extract (KLEE) in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Methods : The cytotoxic effect of KLEE in RAW 264.7 cells was determined by WST-1 assay. Bacterial endotoxin, the concentration of nitric oxide (NO) was analyzed by the Griess reaction. In addition, Western blot analysis was applied to measure the protein expression level of inducible NO synthase (iNOS). The phosphorylated status of the critical inflammatory transcription factor, nuclear factor (NF)-𝜅B, and its upstream signaling molecules, phosphoinositide 3-kinase (PI3K)/Akt as well as mitogen-activated protein kinases (MAPKs), were also measured by Western blot analysis. Results : KLEE was not cytotoxic up to a concentration of 200 ㎍/㎖, and protein expression levels of iNOS and cyclooxygenase (COX)-2, enzymes that counteract NO and prostaglandin (PG) E2 production, were inhibited by KLEE treatment. The phosphorylated status of PI3K/Akt as well as MAPKs including extracellular regulated kinase (ERK), c-jun NH2kinase (JNK), and p38, were significantly attenuated by KLEE treatment in LPS stimulated RAW 264.7 cells. Moreover, one of phase II enzymes, heme oxygenase (HO)-1 which has known for its anti-inflammatory capacity, was strongly induced by KLEE treatment. Conclusion : Consequently, KLEE treatment significantly attenuated the production of NO as well as the expression levels of iNOS and COX-2 in LPS-stimulated RAW 264.7 cells. The inflammatory transcription factor, NF-𝜅B, as well as its upstream signaling molecules, PI3K/Akt and MAPKs, were also diminished by KLEE treatment with statistical significance in LPS-stimulated RAW 264.7 cells. These results suggest that KLEE might be a promising candidate for the attenuation of inflammatory disorders.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.192-200
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• 2022

Nitrogen is the most essential macronutrient for the growth of fruit trees and is important factor determining the fruit yield. In order to produce high-quality fruits, it is necessary to supply the appropriate nitrogen fertilizer at the right time. For this, it is a prerequisite to accurately diagnose the nitrogen status of fruit trees. The fastest and most accurate way to determine the nitrogen deficiency of fruit trees is to measure the nitrogen concentration in leaves. However, it is not easy for citrus growers to measure nitrogen concentration through leaf analysis. In this study, several machine learning models were developed to classify the nitrogen deficiency based on the concentration measurement of mineral nutrients in the leaves of tangor Shiranuhi (Citrus unshiu × C. sinensis). The data analyzed from the leaves were increased to about 1,000 training dataset through the bootstrapping method and used to train the models. As a result of testing each model, gradient boosting model showed the best classification performance with an accuracy of 0.971.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.186-191
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• 2001

Recently, petroleum spray oil(PSO) has been used to control key pests in integrated pest management (IPM) of citrus and other orchards in Australia and USA. In order to clarify the influences of a newly developed PSO (D-C Tron $Plus^{(R)}$) on citrus leaves, 0.33% or 1.0% of PSO were sprayed to potted 4-year-old citrus trees under some kinds of condition, and then the changes of photosynthesis, transpiration, stomatal conductance and chlorophyll fluorescence(Fv/Fm) were determined. When sprayed with 1.0% PSO, the photosynthetic rate, transpiration and stomatal conductance of citrus leaves were decreased by 20%, and then recovered in 20 days after treatment (DAT), while there were little influences by the spray of 0.33% PSO. The value of Fv/Fm decreased more under the $34/24^{\circ}C$ temperature condition than that of under the $30/20^{\circ}C$ and $28/16^{\circ}C$ condition. The high temperature ($50^{\circ}C$ for 10 hours)-treated trees sprayed with PSO 1.0% or PSO 1.0% plus dithianon 1/2000 dilution showed not only the increase of rate in dropped leaf but also the reduced photosynthesis and Fv/Fm compared with $30/20^{\circ}C$ temperature-treated ones. From the results of this study, the spray of 1.0% PSO can inhibit the physiological activities in citrus leaf, particularly under high temperature condition after spray or the mixing-spray with a fungicide (dithianon WP, 75%).

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.80-85
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• 2006

The foliar injuries and absorption rates of calcium compounds in tomato (Lycopersicon esculentum cv. momotaro) and citrus [Shiranuhi(C. Marc. ${\time}C$. sinensis Osbeck)${\time}C$. reticulata Blanco)] were investigated. 0.3, 0.5 and 1.0% of $CaCl_2$, $Ca(NO_3)_2$, $Ca(H_2PO_4)_2$, Ca-EDTA, Ca formate or Ca acetate solution were applied to the leaves of tomato and citrus. The leaf burns were observed only in the foliar applications of Ca-EDTA and $Ca(H_2PO_4)_2$. Ca-EDTA exhibited more serious foliar injury than CaH2PO4. As applied with $^{45}CaCl_2$, $^{45}Ca(NO_3)_2$, $^{45}Ca$ formate or $^{45}Ca$ acetate, the rates of Ca absorptions by tomato and citrus leaves for 7 days were 17 to 32% and 6.6 to 46%, respectively. It meant that the absorption was differently influenced on calcium compounds. In tomato, the order of Ca foliar absorption was $Ca(NO_3)_2$ > Ca formate = $CaCl_2$ > Ca acetate. Although there was no difference in Ca absorption between the adaxial and abaxial parts of tomato leaves, total absorption was greater in expanded leaves than in expanding ones. On the other hand, in citrus Ca foliar absorption from $Ca(NO_3)_2$ or Ca formate was more active than that from $CaCl_2$ or Ca acetate. In conclusion, $Ca(NO_3)_2$ and Ca formate are recommended for the foliar application of Ca in tomato and citrus in order to increase absorption of Ca into their leaves.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.267-274
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• 2000

As the pest of the citrus in Cheju, 69 insect species and 5 animal species were investigated during 1996 to 1998. Of these, Panonychus citri, Phyllocnistis citrella, Aphis citricola, Aphis gossypii and Frankliniella occidentalis are major pests. Especially, F. occidentalis and Peridroma saucia are very important species because of increasing damage. The number of pests species injuring leaf, branch, fruit and flower of the citrus are 36, 16, 41 and 2 species respectively. The rate of damaged fruits by pests is 20.5% in 1997 and 18.6% in 1998 and the rate of bad quality fruits is 6.4% and 6.7% respectively.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.145.2-146
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• 2003

To investigate occurrence and variability of satsuma mandarin ( Citrus unshiu)-infecting viruses in Jeju island, several sets of diagnostic RT-PCR primers were designed and applied to samples collected randomly. Each primers set used in this survey was designed to detect Satsuma dwarf virus (SDV, Sadwavirus) and Citrus mosaic virus (CiMV) which is reclassified as an isolate of SDV (SDV-CiMV, Saduavirus). RT-PCR methods could detect SDV-CiMV and CTV from leaf . samples of unshui citrus. CTV was the prevalent and SDV-CiMV was not common in Jeju island. RT-PCR product of SDV-CiMV-JJl2 were cloned and sequenced. Sequence of the isolate revealed that it was 96.9 ％ identical to SDV-CiMV-Jp isolate at the nucleotide level. SDV-CiMV-JJl2 was propagated on Physalis floridana and sequencing of entire sequences of genome is in progress. Variability of SDV in Jeju island was confirmed by sequence comparisons and restriction mapping analysis.