• Food Science and Preservation
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• v.16 no.3
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• pp.317-320
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• 2009

'Niitaka' (Pyrus pyriforia) has been the major cultivar of the Asian pear since the 1970s, and yielded about 70% of pear production in South Korea in 2002. When Chuseok (Korean Thanksgiving Day) is earlier than the fruit maturation period, farmers seek to advance the harvesting date to keep pace with the increase in consumer demand caused by the holiday. However, unripened fruit is of suboptimal marketable value because the flesh has a low soluble solid content, the fruit color is not attractive, and stone volume is high. Compost treatment can enhance soil microbial activity and affect soil chemistry, which may accelerate fruit maturation and allow an earlier harvesting date. Therefore, we examined the effect of 2 years of compost application on the fruit quality of Asian pear trees grown under conventional management conditions. The Hunter "L" and "a" values were higher in compost-treated fruit, which also showed greater sweetness and lower acidity than did conventional fruit. The stone volume was reduced and fruit calcium concentration was increased by compost treatment. Therefore, compost treatment may advance fruit harvesting owing to the increased marketability afforded by attractive skin color, sweetness, and reduced stone volume.

• Food Science and Preservation
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• v.17 no.2
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• pp.169-173
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• 2010

Although fruit grown under sustainable farming conditions is believed to be healthier for humans than is fruit grown by conventional cultivation, little scientific information on the characteristics of fruit produced using these two farming systems is available in Korea. Therefore, weinvestigated fruit quality, total polyphenolic contents, and anti-oxidant activities in 'Niitaka' pears grown under sustainable and conventional farming management systems. Treatmentsincluded use of a chitin compost admixed with liquid chitin fertilizer (plot A), and use of a chitin compost admixed with liquid chitin fertilizer treated by infrared radiation (plot B). Plots C and D used conventional management systems. Fruit qualities at harvest differed between both sustainable plots A and B and the conventional plots C and D. The average values of firmness and total polyphenolic content in fruit harvested from sustainable plots were not significantly greaterthan those of fruit grownin conventional plots, after 60 days of storage. Fruit grown in all plots had low polyphenol oxidase (PPO) activity at harvest but this increased during storage. Fruit from sustainable plot B showed an increased electron donating ability compared with fruit grown using the other systems.

• Korean journal of applied entomology
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• v.24 no.1 s.62
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• pp.19-24
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• 1985

Alternaria mali isolated from infected apples in storages and orchards of the four main apple growing areas of Taegu, Yesan, Jungup and Chungju in Korea was tested with various fungicides added in PSA medium. The fungal tolerance varied with little difference by orchard area and with great difference by king and concentration of fungicide. Minimum inhibitory concentration (MIC) of chlorothalonil and captafol was $100,238{\mu}g\;and\;81,000{\mu}g/ml$, respectively, showing low effects with high fungal tolerance; of iprodione and folpet was $3,285{\mu}g\;and\;3,000{\mu}g/ml$, respectively, showing moderate effects with moderate fungal tolerance; and of oxidong, polyoxin and polydong was $1,000{\mu}g,\;900{\mu}g\;and\;500{\mu}g/ml$, respectively, showing high effects with low fungal tolerance. Mycelial growth, conidia formation and conidia germination of the fungus showed a similar trend of response to the seven fungicides.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.29-39
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• 2017

To compare the features of ground-dwelling invertebrates according agroecosystems, we selected paddy fields, dry fields, orchards in the Eastern region of Korea. The surveys were performed by using pit-fall traps twice per year from 2013 to 2015. Total 6,420 individuals of 172 species belonging to 13 orders, 58 families were investigated in the Eastern region, the species of Hymenoptera (38.26%), Orthoptera (16.28%) accounted large portion of the communities. In the geographical observation, invertebrates were caught was 2,983 individuals in Gyeongsangnam-do, the diversity index of Gyeongsangbuk-do community was higher than of the others and abundance and species richness of paddy field were higher than from dry field or orchard. To understand the relation between taxonomic groups and environmental factors, we carried out the canonical correspondence analysis and hierarchical clustering. As a result, Homoptera, Blattaria, Isoptera, and Coleoptera were positively related to soil pH, soil temperature, and moisture contents, and negatively related to the others. Invertebrate community also were patterned dependently by type of ecosystems. This results were shown that distribution of invertebrates is a few influenced the relationship of the space habituated invertebrates and environmental factors.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.61-67
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• 2017

Two major sex pheromone components (Z-8-dodecenyl acetate and E-8-dodecenyl acetate) are known in the peach fruit moth, Grapholita molesta. From a putative biosynthetic pathway of these sex pheromone components, delta 10 desaturase ($10{\Delta}$ DES) has been proposed to play a crucial role in synthesizing a species-specific stereoisomer of the double bond. However, its molecular identity was not known. This study determined a putative desaturase (Gm-comp1575) as a $10{\Delta}$ DES candidate from G. molesta transcriptome constructed from the sex pheromone gland. Its open reading frame encodes 370 amino acid sequence with a predicted molecular weight at 43.2 kDa and isoelectric point at 8.77. It was predicted to have four transmembrane domains and six glycosylation sites at N-terminal or cytosolic domains. A phylogenetic analysis with its predicted amino acid sequence indicated that Gm-comp1575 is closely related with known $10{\Delta}$ DES genes of other insects. Gm-comp1575 transcript was detected in female adults at sex pheromone gland and other abdominal tissues. RNA interference of Gm-comp1575 significantly reduced attractiveness of virgin females in apple orchard compared to control females. These results suggest that Gm-comp1575 is associated with sex pheromone biosynthesis of G. molesta.

• Journal of Forest and Environmental Science
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• v.36 no.3
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• pp.207-218
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• 2020

Ashwagandha is an important ancient medicinal crops, being affected with many diseases, among which leaf blight caused by Alternaria alternata has become the constraint resulting in huge yield losses. Continuous usage of chemical methods leads to environment, soil and water pollution. Whereas biological control of diseases is long lasting, inexpensive, eco-friendly and harmless to target organisms. In this context, it is aimed to evaluate five Trichoderma strains viz. Trichoderma virens IMI-392430, T. pseudokoningii IMI-392431, T. harzianum IMI-392432, T. harzianum IMI-392433 and T. harzianum IMI-392434 as bio-control efficacy against A. alternata and growth promoting effect in Ashwagandha. All the Trichoderma strains had varied antagonistic effects against the pathogen. In dual culture technique, the strain T. harzianum IMI-392433 showed maximum percentage inhibition of mycelial growth (54.89%) followed by T. harzianum IMI-392432 (53.83%), T. harzianum IMI-392434 (48.94%) and T. virens IMI-392430, (43.62%) against the pathogen, while the least inhibition percentage was observed with the T. pseudokoningii IMI-392431 (36.60%). The culture filtrate of the Trichoderma strain, T. harzianum IMI-392433 recorded highest inhibition on the mycelial growth (39.05%) and spore germination (80.77%) of pathogen and the lowest was recorded in T. pseudokoningii IMI-392431 (20.45 and 50%). Moreover, seeds treated with spore suspension of the strain T. harzianum IMI-392433 reduced the percentages of disease severity index significantly. The strain T. harzianum IMI-392433 also significantly increased seed germination %, seedling vigor and growth of Ashwagandha. The correlation matrix showed that root yield per plant of Ashwagandha had significant and positive correlation with plant height (r=0.726^⁎⁎), number of leaf (r=0.514^⁎⁎), number of primary branch (r=0.820^⁎⁎), number of secondary branch (r=0.829^⁎⁎), fresh plant weight (r=0.887^⁎⁎), plant dry weight (r=0.613^⁎⁎), root length (r=0.824^⁎⁎), root diameter (r=0.786^⁎⁎), root dry weight (r=0.739^⁎⁎) and fresh root weight (r=0.731^⁎⁎). The significant and negative correlation (r=-0.336^⁎⁎) was observed with the root yield and percentages of disease severity index. The study recognized that the T. harzianum IMI-392433 strain performed well in inhibiting the mycelial growth and reduced the percentages of disease severity index of pathogen as well as increased the plant growth in Ashwagandha.

• Korean journal of applied entomology
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• v.57 no.2
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• pp.105-115
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• 2018

The comstock mealybug is one of the serious insect pest in pear. It is necessary effective control methods such as attractive sex pheromone. Using sex pheromones is necessary for studying the physiology and ecology of insect pests. In the present study, the sex pheromone of comstock mealybug was used for investigating the flying acts of the adult male. As temperature increased, the development period of eggs shortened, but it was longer at $30^{\circ}C$. The mean number of eggs laid was 482 at $25^{\circ}C$ and males constituted 37% of the experimental population at $30^{\circ}C$. The flight of the male comstock mealybug was mostly restricted to a 2-4 hour period after sunrise, even if condition of light period is changed. Male mealybugs were incapable of upwind flight towards an attractant when air velocity was 1.5 mph. Preference of height was tested in a pear orchard. The ineffective heights of the traps were 2 and 2.5 m, whereas the effective heights were 1 and 1.5 m. Many captured males at 0.5, 1, and 5 m, and the number of captured males were similar in 10, 15, and 20 m. Male mealybugs were captured up to a distance of 50 m, suggesting that it is possible to control the male mealybugs that are more than 50 m away when sex pheromone traps are used.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.29-34
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• 2003

Dispersion pattern for adult citrus red mite (CRM), Panonychus citri (McGregor) using by Taylor's power law (TPL) and Iwao's patchiness regression (IPR) was determined to develop a monitoring method on citrus orchards, on Jeju, in Autumn season, during 2001 and 2002.CRM population was sampled by collecting leaves and fruits. The relationships of CRM adults between leaf and fruit were analyzed by different season. The regression equation for CRM adults between leaf (X) and fruit (Y) was ln(Y+1) : 1.029 ln(X+1) ( $r^2$ : 0.80). The density of CRM was higher on fruit than on leaf according to fruit maturing level. TPL provided better description of mean-variance relation-ship for the dispersion indices compared to IPR. Slopes and intercepts of TPL from leaf and fruit samples did not differ between sample units and surveyed years. Fixed-precision levels (D) of a sequential sampling plan were developed using Taylor's power law parameters generated from adults of CRM in leaf sample. Sequential sampling plans for adults of CRM were developed for decision making CRM population level based on the different action threshold levels (2.0,2.5 and 3.0 mites per leaf) with 0.25 precision. The maximum number of trees and required number of trees sampled on fixed sample size plan on 2.0,2.5 and 3.0 thresholds with 0.25 precision level were 19, 16 and 15 and their critical values T$_{critical}$ at were 554,609 and 659, respectively. were 554,609 and 659, respectively.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.51-57
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• 2008

This study demonstrates a variability in efficacy of mating disruption against the oriental fruit moth, Grapholita molesta, populations infesting apples cultivated in differential environmental conditions. Throughout the growing seasons, trap catches of G. molesta male moths and damaged leaf and fruit were examined to evaluate the efficacy of a commercialized mating disruptor. Treatment of the mating disruptor significantly reduced the trap catches of male moth in treated plot, compared to those of the untreated plot. This reduced trap catches were significantly correlated with leaf and fruit damage. Moreover, the highest host damage occurred in June just after the highest overwintering adult peaks in both plots. The treatment of mating disruptors in Chungsong effectively disrupted the overwintering population in April and May, resulting in no noticeable host damage during the following growing seasons. However, there was a marked difference in host damage between two plots, especially in late seasons. Variation in the efficacy of mating disruption technology in terms of host damage appeared to be related with nearby pheromone-untreated orchards, which may result in the immigration of gravid females.

• Korean journal of applied entomology
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• v.53 no.2
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• pp.177-183
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• 2014

The ussur brown katydid, Paratlanticus ussuriensis (Orthoptera: Tettigoniidae), causes substantial damage in orchard areas in South Korea. Daily rhythm and mating behaviors were investigated in last instar nymphs, immature adults and mature adults of P. ussuriensis. The daily rhythm was repeated upon resting, moving, and feeding. The daily rhythm of the movement behavior similar in both last instar nymphs and immature adults. Last instar nymphs becoming active at 10:06 and ceasing activity at 21:12 in average. Immature adults becoming active at 11:30 and ceasing activity at 20:08 in average of totally 10 individuals. However, mature adults showed a different active time of 15:30. Generally, behavior was affected by the conditions of their environment, especially temperature. Mature adults activated later than nymphs and immature adults. Mature adults display mating behavior at a particular time of day (approximately 20:00). P. ussuriensis showed a mating behavioral sequence which was similar to related species in completely retaining the spermatophylax. Females took 270 min to 360 min to completely retain the spermatophylax. The daily rhythm of P. ussuriensis, indicating its occurrence and ecology, could be useful as basic data for managing field populations of P. ussuriensis.