• Korean journal of applied entomology
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• v.50 no.1
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• pp.29-37
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• 2011

A remote sensing pheromone trap called IT pheromone trap (Korean patent: 10-0982563) was applied to monitor overwintering population changes of the oriental fruit moth, Grapholita molesta, for three successive years in apple orchards. Males of the overwintering populations were attracted during April and May. However, the occurrence peak was delayed and extended to early June in 2010, at which the average spring temperature was significantly lower than the previous years. These overwintering populations could be monitored by the remote-sensing pheromone trap. When the remote-sensing pheromone traps were deployed to apple orchards of different provinces in Korea in 2010, the maximal overwintering populations of G. molesta were monitored at May in all areas. However, the population sizes monitored were significantly different among different localities. This study suggests a practical application of IT pheromone trap to monitor G. molesta in field conditions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.187-196
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• 2009

The objectives of this study were to evaluate the different cutting dates on the changes of feed quality among five cereals (barley, wheat, rye, triticale and oat) for whole crop silage. Field trials were conducted at paddy field in Yesan, Chungnam Province and the aerial parts were clipped 10 days from 15 March to 15 June. Changes of acid detergent fiber (ADF) content in relation to different cutting dates was described by a quadratic curve for 5 winter cereals crops. ADF content reached a maximum at 5 days after heading in barley cultivar 'Youngyang', 7 days in wheat 'Keumkang', 18 days in rye 'Gogu', 1 days in triticale 'Shinyoung' and 10 days in oat 'Samhan'. Neutral detergent fiber (NDF) content were linearly increased as growing after overwintering and stagnated or slightly decreased after heading. The crude protein were linearly decreased throughout the growth period of 5 whole crop cereals. Digestible dry matter (DDM) content were decreased from early stages to heading and subsequently increased as grain filling. Relative feed value (RFV) for 5 crops were decreased as growing and subsequently increased as grain filling after heading. Barley cultivar for only forage use 'Youngyang' were lower at ADF and NDF content and higher at DDM and RFV after heading than those of other cereals for forage use. So, barley for whole crop silage was a good crop with high feed quality and high proportion of spikes compared with other winter cereal crops. Wheat cultivar for grain 'Keumkang' were higher at crude protein than those of other four cereals from overwintering to maturing and were higher at DDM and RFV after heading than those of rye, triticale and oat. Rye cultivar with cold tolerant and high fresh yielding 'Gogu' were highest at ADF and NDF content and lowest at DDM content and RFV. So, rye was a crop with low quality for forage use compared to other winter cereal crops. Triticale cultivar with flourishing and high yielding 'Shinyoung' was intermediated between barley and rye, and were linearly increased at DDM yield by different cutting dates. Oat cultivar with cold tolerant and high tillering 'Samhan' were lower at ADF and NDF content and higher at crude protein before heading, but after heading, there are not especially advantages compared to barley, wheat or triticale.

• Korean journal of applied entomology
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• v.47 no.3
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• pp.201-208
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• 2008

Spring phonology of the oriental fruit moth, Grapholita molesta, was monitored using sex pheromone traps in apple cultivating areas. Their occurrence was earlier in southern areas and their population sizes were significantly different among orchards even in a local cultivating zone. The overwintering populations appeared to move between local orchards, based on the fact that monitoring data obtained at the sites between orchards were similar to those of nearby orchards. However, within orchards, these adult movements appeared to decrease and showed skewed occurrences at the side of upwind direction or close to neighboring orchards. At initial occurrence peak(April 20-25), the ovenvintering populations of the different localities were collected and analyzed in their genetic distances. PCR-RAPD analysis indicated that there were significant genetic differences among the overwintering populations of G. molesta. This genetic differentiation of overwinterin populations may be due to genetic bottleneck following differential selection pressures against the subpopulations of G. molesta during winter on the basis of the RAPD analysis that each early spring population was significantly different to its previous fall population in the same locality.

• Asian Journal of Turfgrass Science
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• v.12 no.3
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• pp.225-236
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• 1998

The white grubs in turfgrass were investigated from 15 golf clubs in 7 provinces and 2 metropolitan cities. 12 white grub species were collected and 11 species in 8 genera including oriental beetle, Anomala orientalis were identified but 1 species was not identified. The oriental beetle grub was the most serious pest in turfgrass out of them. The brown chafer, Adoretus tenuimaculatus was widely distributed species collected from 6 golf clubs, Maladera castanea was collected from 5 golf clubs and A. orientalis, Holotrichia kiotoensis, and M. orientalis were collected from 4 golf clubs. The white grubs, their density, and distribution depth were also observed at tee, fairway, and green from Yongweon, Daegu, and Dongrae golf clubs. A. orientalis was dominant species in overwintering season but A. tenuimaculatus was dominant one in unoverwintering season. The density of white grubs was low in the green compared with tee or fairway. Distribution depth was different depending on season in Daegu and Dongrae golf clubs but not different in Yongweon golf club. Although there showed no differences in white grub species depending on turfgrass but density was different, that is, A. tenuimaculatus was abundant in Zoysia matrella while A. orientalis abundant in Poa pratensis. The density of A. orientalis grubs was higher in older golf courses but there showed no differences in white grub species depending on the age of golf club.

• Korean journal of applied entomology
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• v.11 no.1
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• pp.31-35
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• 1972

1. Continuous light induced more conidia than alternating light and darkness treatment in isolate Chinju 1. Isolate Suwon 3 produced much more conidia on synthetic medium than Chinju 1 in light. Conidial formation in Suwon 3 increased remarkably with alternate light and darkness in 8 days incubation. 2. Light was essential for perithecial formation in Chinju 1. No matured perithecia were observed in Suwon 3 with any treatment. Abundant perithecia were produced in Chinju 1 but only perithecial initiation occurred in Suwon 3. Suwon 3 produced significantly more conidia than Chinju 1, while perithecial formation was reversed. 3. Conidial numbers in soil decreased significantly through the winter at 10, 30 and 50 per cent soil moisture, with the most striking decrease at 10 per cent levels, but the number recovered again beginning in March, regardless of the soil moisture. The above results provide us a useful clue to support the possbility the conidia may serve as a primary inoculum.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.3
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• pp.70-73
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• 1992

사료작물 저온발아성(低溫發芽性)은 수수 $\times$ 수단그라스잡종들이 좋았고 옥수수와 수단그라스는 비교적 저조하였고 PGE에 종자침지처리가 이탈리안라이그라스의 저온발아에 효과적이었다. 간척지의 수수파종시 염해 방지에는 모래를 파종후 피복하여 제염(除鹽) 효과를 얻을수 있었다. 수수류의 토양수분조건에 대한 광합성 연구는 포장용수량의 $60\sim80%$의 조건에서 광합성이 가장 왕성하였고 건물수량도 동일한 결과를 나타내었다. 옥수수의 광이용과 초형과의 관계연구는 이삭상부 엽각의 직립화는 밀식 조건에서 광이용성이 증가되었고 건물 및 종실수량에서 종수가 있었다. 또 밀식화에 따라 직립화 경향이 현저하였으며 옥수수의 다수성초형의 육성이 요청되었다. 질소시비에 대한 청예류의 생장 반응 연구들은 수단그라스에서 10a당 40Kg까지는 건물수량생산을 증가시켰으나 80Kg/10a 사용시는 질산태질소함량이 중독위험치를 초과하였다. 이러한 질산태질소의 중독위험은 6엽기까지 존재하였고 청산중독의 위험농도는 4엽기 이전까지, 또 18/$8^{\circ}C$의 저온조건에서 나타났다. 옥수수의 적정재식 밀도는 10a당 16.600본까지 밀식할수록 증가되었으나 가소화수량과 종실수량은 5.500본과 10Kg/10a 에서 최고치를 나타내었고 질소 추비 효과는 대관령 같은 고산지대에서는 나타나지 않았다. 맥류의 총체(總體)사료 이용성은 호밀, 밀, 보리 순(順)으로 저하하였고 파종시기가 빠를수록 월동성이 향상되었으며 수확적기는 출수후 24일경이었다. 호밀의 청예이용에는 월동후 2회예취와 12cm높이가 건물수량과 TDN수량을 높힐 수 있었다. 수수$\times$ 수단잡종의 출수기 이전 예취는 고사 경비율을 줄일 수 있었고 년 2회 예취와 예취높이 10cm가 가장 좋았다. 유채는 생육기간이 길어질수록 수량은 증가하였고 소화율의 감소도 현저하지 않았다.

• Korean journal of applied entomology
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• v.54 no.2
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• pp.73-81
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• 2015

A Cohort based model for temperature-dependent population dynacmics of Riptortus pedestris was constructed by using a commercial software (DYMEX) and seasonal occurrence along with pesticide treatments effect was simulated and validated with pheromone trap data. Ten modules of DYMEX software were used to construct the model and Lifecycle module was consisted of seven developmental stages (egg, 1 - 5 nymphal instars, and adult) of R. pedestirs. Simulated peaks of adult populations occurred three or four times after the peak of overwintered populations which was similar to those observed from pheromone trap catch. Estimated dates for the second peak were quite similar (1-2 day difference) with those observed with pheromone trap. However, the estimated dates for the first population peak were 9-16 days later than the observed dates by pheromone trap and the estimated dates for the last peak were 17-23 days earlier than the observed dates. When insecticide treatments were included in the simulation, the biggest decrease in R. pedestris adult density occurred when insecticide was applied on July 1 for the first peak population: the estimated adult density of the second peak was 3% of untreated population density. When insecticide was assumed to be applied on August 30 for the second peak population, the estimated adult density of the following generation was about 25% of untreated population and the peak density of the following generation reached about two weeks later than untreated population. These results can be used for the efficient management strategies for the populations of R. pedestris.

• Korean journal of applied entomology
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• v.26 no.2 s.71
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• pp.99-106
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• 1987

Three post-harvest fields each in four rice growing areas, Iri, Naju, Jinju and Taegu were randomly selected and surveyed during December 1986 to examine sclerotial density of Rhizoctonia solani overwintering in the field. Surface soil of $0.09m^2$ area was sampled in each field with three replications and sieved to collect sclerotia. Germiability and pathogenicity of collected sclerotia were examined in the laboratory. Number of sclerotia $({\times}10^6)/ha$ in Iri, Naju, Jinju, and Taegu was estimated from the sample as 2.7, 1.2, 0.7 and 0.6, respectively. Based on sample variance with simple random sampling in each area, number of sampling required for estimating average sclerotial density with the precision of 10% apart from a chance of 1 in 20 was calculated to 41, 132, 232, and 395 for Iri, Naju, Jinju and Taegu, respectively. Percentage of germination of sampled sclerotia on potato sucrose agar (PSA) ranged from 42 to 78% depending on the area, and averaged 60%. About 49% of the germinated sclerotia were pathogenic to a rice cultivar Jinheung that was used to test pathogenicity of the sclerotia. Proportion of viable sclerotia that have both germiability and pathogenicity was thus estimated to 0.29 of total sclerotia collected. R. solani cultures obtained from the sclerotia could be distinguished into three groups based on colony morphology on PSA. Size and number of sclerotia formed on PSA differed between group but were not associated with pathogenicity to Jinheung.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.249-255
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• 1995

These experiments were conducted to investigate the life history and the seasonal fluctuation of population density of tea red spider mite, Tetranychus kanzawai Kishida and to observe its natural enemies in the southern area. Under field-cage conditions, tea red spider mite occurred 11~12 generations. The average periods from egg to adult emergence were 8.7~13.1 days in summer and 12.6~24.9 days in spring and autumn. The average longevities of adults were 15.5~21.9 days in summer and 25.1~31.6 days in spring and autumn. The average number of eggs laid per female were 45.1 in summer and 52.6 in spring and autumn. Tea red spider mite population showed two peaks during April-June, and appeared third or forth peak during October-November. The density of all the stages was the lowest in July through August. Tea red spider mites stayed at lower parts of tea plants in March but they moved to upper parts in April though June, and they again moved to lower parts after autumn. Tea red spider mite overwintered as all stages. Adults were the dominant overwintering stage during this stage. The surveyed natural enemies of the tea red spider mite were 7 species including Amblyseius longispinosus (Evans), A. eharai Amitei et Swirski, Anystis baccarun (L), Agistemus fleschneri Summers, Orius sauteri Poppius, Oligota yasumatsui Kistner and Scolothrips sp.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.848-856
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• 2016

The purpose of this study is to determine the impact on settlement pattern of wintering swans by distribution of rapidly spreading lotus in Junam reservoir. When we investigated the relationship between the spreading lotus and population variation of the wintering swans in all around Nakdong-river estuary, the spreading lotus did not affect the number of swans in Junam reservoir. The occupation ratio of lotus distribution continuously increased from 13.2%(2013) to 19.0%(2014). Before we begin with the investigation, we compared two particular groups: inside of lotus community and far (>100 m) water area from the border of lotus community. At the first survey(2013.12.17), we observed 3.1 times more swan population in the inside, comparing with far water area. The third(2014.01.29.) and fourth(2014.12.03) inquiries also showed respectively 5.5 and 7.5 times higher swan population in the inside and near water area. The second observation was conducted during visitors were increased so these phenomenon was not observed. This result might be explained as the similar environmental condition of habitate for swan and lotus such as less than 1 m water depth. However, we considered that lotus and swan were not relation of conflict due to increasing both lotus community and swan population at the same time. According to the observation that inhabitation density of wintering swans is significantly high in near lotus communities area, at least spread of lotus did not negatively affect the wintering swans.