• ALGAE
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• v.18 no.2
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• pp.177-181
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• 2003

Variation in seasonal growth, phenology and periodicity in spore shedding in Polysiphonia platycarpa $B{\oslash}rgesen$ occurring on the coast of Visakhapatnam, India, have been described to know the growth behaviour, reproductive periodicity and spore producing capacities. This alga occurs for a short period from December to May in the intertidal region of the Visakhapatnam coast, showing maximum growth during January/February. Tetrasporophytic, carposporophytic and antheridial plants were observed in all months of their occurrence in the field. But the vegetative plants were not seen in January and February and all the plants collected were reproductive. The tetraspore and carpospore shedding was observed during all the six months of their occurrence.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.141-144
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• 1990

Seasonal change in the reproductive pattern of the marine Cladoceran Podon polyphemoides, was studied using materials collected monthly during the period from January to December 1986 in Yongil Bay, Korea. The relative abundance of P. polyphemoides exceeded $10\%$ of total zooplankton in July. While the species remained as a minor components of the zooplankton community during the other periods of occurrence from June to December. Occurrence of sexual individuals of P. polyphemoides (males and gamogenetic females) in higher proportion in cold months ($30\%$ in November and $40\%$ in December) suggests that resting egg production of this species is largely confined to cold monthis in Korean waters as an overwintering strategy.

• Journal of the Korean Society of Tobacco Science
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• v.5 no.1
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• pp.11-17
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• 1983

The tobacco moth, Ephestia elutella Hubner (Lepidoptera: Pyralididae), was first reported one of the serious of stored tobacco in Korea in 1939 (8). In recent years, tobacco moth lavae were observed infesting in all of the tobacco storage warehouses in this Country. Adults of the tobacco moth for the seasonal occurrence were studied in the three and four regions in 1981 and 1982, respectively. This species was caught from early May to late October in all regions for both years. In 1981, the first emergence peak was in late May to late at Andong, early June at Suweon and the second one in middle August in both regions. In 1982, on the other hand, there were three peak times, late May and July, and middle September. But the relate size of the peaks was different in two years; the second peak showed about 66% of the total number of tobacco moths captured in the whole year in 1981 at Suweon and 59% of those at Andong, while the first peak had 32% at Suweon and 57% at Shintanjin in 1982. This difference in relative peak sizes was discussed.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.165-167
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• 2003

The seasonal occurrence of smaller clearwing moth (Synanthedon tenuis) was monitored with sex pheromone traps in sweet persimmon orchards in Gimhae and Jinju in 1998, 2001, and 2002. Results indicated that it occurred in two generations a year. The first generation of the moth occurred from mid-May to early July, and the second one_from late July to late September, showing the peaks in early June and early to mid-August, respectively.

• The Korean Journal of Ecology
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• v.19 no.1
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• pp.31-37
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• 1996

The chigger mites known as the vectors of Tsutsugamushi disease seriously increased due to the expansion of their habitats by the change of farmland into idle land, arboreta and golf courses with the progress of industrialization. These mites were surveyed for their nymphs in soil of four areas located in the northern part of Kyonggido known as the outbreak areas of Tsutsugamushi disease. Total number of the chigger mites collected in the soil of four surveyed areas was 2576, and two genera and ten species including Leptotrombidium palpale were indentified. Among them L. pallidum was the dominant species with the highest occurrence rate of 62 percent. Nine species occurred on the bank of Changrungchon that has been idled for more than ten years, but six or seven species occurred in Wonhundong and Ilsandong that hans been idled for less than five years. The number of individuals collected was also higher in Changrungchon than the other sites. Seasonal occurrence of these mites showed a peak with 166 mites in November on the west slope and another with 192 mites in February on the east slope of the bank of Changrungchon, but none in June. Component ratio of individual numbers for L. palpale, L. pallidum, L. orientalis and L.scutelaris were 19, 62, 9 and 3 percent, respectively. Individual number of L. pallidum and L. scutelaris appeared to some extent of 397 and 23 mites, respetively.

• Asian Journal of Atmospheric Environment
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• v.10 no.1
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• pp.22-31
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• 2016

Active fire products from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observation during the 16 years from 2000-2015 were analyzed to estimate spatial and temporal variations of wildland fires over East Asia (region of interest: $20^{\circ}N-55^{\circ}N$, $100^{\circ}E-150^{\circ}E$). GLOBCOVER 2009 land cover data were also used to investigate the trend in wildfire occurrence with respect to each land cover type. Statistical analysis showed that the highest number of wildland fires occurred in the evergreen and vegetation covered areas, and strong seasonal variations were found in these areas. Total numbers of fires were 283,683 and 202,543, respectively. In particular, the wildland fires in croplands occurred mainly during summer season and distinguishable increasing trends were found. The correlations between number of wildland fires and air pollutants, such as black carbon, organic matter, and carbon monoxide, were also calculated in order to investigate the intensity of the air pollution caused by the wildland fires. Positive correlation between total column carbon monoxide contents and the occurrence of wildland fire was found. In addition, this correlation was higher than the correlation between fire occurrence and black carbon or organic matter. These results indicate that a significant amount of carbon monoxide originated from the wildland fires and influenced the regional atmospheric environment in East Asia.

• Research in Plant Disease
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• v.8 no.1
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• pp.45-49
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• 2002

Seasonal occurrence of strawberry anthracnose in greenhouses caused by Colletotrichum sp. was examined from 1997 through 1999 at three locations, Kyeongju, Goryeong, and Cheongdo in Kyungbuk province, Korea. Also some factors related to the anthracnose infection such as initial infection sites, inoculation methods, and soil nature were studied through in vitro and field experiments. The anthracnose disease begun to occur from 15 days after transplanting in early October, and continued but gradually decreased thereafter for 2 months until December, After transplanting, initial infection mainly occurred through the runner of which the tissue was more susceptible to the anthracnose than those of the leaf and petiole when the fungal mycelial disk was inoculated. Postplanting inoculation by irrigation with spore suspension was much more effective in inducing the anthracnose disease than preplanting soil mix. However without inoculation, no or little anthracnose occurred regardless of commercial, non-cultivated or diseased field soils when healthy seedlings were planted. This suggests that occurrence of strawberry anthracnose in fields may be related to contamination of plant propagules with the anthracnose pathogen.

• Korean journal of applied entomology
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• v.34 no.2
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• pp.106-111
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• 1995

This study was carried out to investigate the effect of mass trapping with synthetic sex pheromone on seasonal occurrence of, the Beet amyworm (BAW) Spodoptera exigua, and on suppress of their density in Chonnam province from 1992 to 1994. Adult males of BAW were colllected by the trap from early through early November. The numbers began to increase abruptly from early July, and forming three peaks on mid July, early August and early September. Yearly occurrence and the area damaged by the BAW varied in relation to weather condition. Especially, low temperature and heavy rainfall in August 1993 seems to have affected to reduce the BAW population. The pheromone trap attracted higher numbers (1.5~2.3 times) of BAW adult than ordinary light rap. And the BAW population in vinyl hose was noticeably reduced when more than 10 pheromone traps were operated per 330$\m^2$ of vinyl house.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.49-54
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• 2004

The oriental tobacco budworm, Helicoverpa assulta (Guenee) is a major pest of red pepper in Korea. Insecticide spray is a prevalent control tactic in most farms, but an effective control is difficult because the larvae are protected inside the fruit. Objective of this study was to investigate the seasonal occurrence of the male moths using pheromone trap and to evaluate the control efficacy of insecticide applications based on the trap catch data at red pepper fields in Suwon. The results of pheromone trap catch during three years showed that the moth flight activity occurred from late May to early October. Peak periods of the adult flight, which are indicators of each generation, occurred in late June, late July-early August, and late August-early September. Trap catches during the overwintering and first adult generation were closely linked with subsequent damage. Although the trap catch during the second generation was higher than the previous generations, damage level caused by this generation larvae was low. Experiment results revealed that fruit damage by H. assulta could be effectively reduced by five sprays of insecticides based on the trap catch data throughout the season.

• Korean journal of applied entomology
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• v.56 no.3
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• pp.261-265
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• 2017

Currently, clearwing moths and peach fruit moths are considered economically important pests of jujube in Boeun, Chungbuk, Korea. However, until now, specific studies on occurrence of the major pests of jujube in Boeun area, which could be useful for pest control, have not been carried out. In this study, seasonal occurrence of three pest moths (Synanthedon bicingulata, S. haitangvora, and Carposina sasakii) in jujube orchards was monitored using sex pheromone traps. Synanthedon bicingulata and S. haitangvora were monitored from 2013 to 2015. Adults of both species were captured from May to October, with two peaks in their occurrence: mid-June and mid-September for S. bicingulata, and mid- to late-June and mid- to late-September for S. haitangvora. However, S. haitangvora occurred in lower numbers than S. bicingulata. Adults of C. sasakii were captured from 2014 to 2016. From May to October, two peaks were observed in their occurrence in mid-June and in late-August to mid-September and the second peak was lower than the first. Thus, the life histories of these pest moths of jujube should be studied in detail for an effective pest control.