• Research in Plant Disease
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• v.10 no.3
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• pp.198-202
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• 2004

The overwinter and survival of Colletotrichum gloeosporioides and Glomerella cingulata in strawberry tissues under field conditions was investigated in 2001 and 2002. The rates of overwinter survival in plant petiole, runner and crown were 68.7,14.3, and 26.7％, respectively. But, under field condition, viable conidia of overwinter were not detected at the surface, 3, 5, and 10 cm depths of soil. To investigate the survival ability in soil and plant debris, C. gloeosporioides and G. cingulata isolates from strawberry were examined in laboratory and field. The viability of conidia was rapidly declined in all the treatments, with a 40％ reduction in population within 10 days. In soil, the survival ability of G. cingulata conidia was similiar to that of C. gloeosporioides. The survival rate of conidia was highest under cool and dry soil conditions, and was decreased by increasing both soil temperature and moisture content. Similar results were also obtained under the condition that infected petioles were buried in soil. Results suggested that conidia as well as plant debris might be a main primary inoculum source of strawberry anthracnose.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.6
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• pp.382-386
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• 2000

This study was conducted to know the optimum conditions for overwinter culture of sweetpotato stems in PE film house. The stems will be used as transplant shoots in the next year instead of sprouts produced from storage roots. Sweetpotato stems were cut at field on harvest season and planted in PE film house under three different conditions of PE film mulching, tunnel, or mulching plus tunnel in comparison with the non-treatment of PE film on October 10 and November 10. The survival rate of sweetpotato stems, which was evaluated on April 10 after overwinter, was higher in the treatment planted on October 10 than that on November 10, and with PE film treatments, it was higher in tunnel or mulching plus tunnel than that of the non-treatment of PE film. The survival rate of sweetpotato stems to planting densities was 95-96% in 10$\times$2cm (333 stems/$m^2$) or in 10$\times$4cm (250 stems/$m^2$) when compared with 10$\times$2cm (500 stems/$m^2$). The survival rate under low temperature showed 95% until 20 days at 5$\pm$1$^{\circ}C$, and 0% within 5 days at 2$\pm$1$^{\circ}C$. From these results, it was concluded that there were optimum conditions that cutting time is middle October, planting density is 10$\times$3cm, and minimum maintenance temperature is 5$^{\circ}C$ in growing conditions of sweetpotato stems. Root yield produced by trans-planting shoots using the stems was similar to yield by shoots produced from roots, and the survival rate was not different among varieties.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.210-216
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• 2018

This experiment was carried out to study the effect of difference in cold-tolerance and growth characteristics of variety on forage productivity of Italian ryegrass(IRG) in middle region of Korea from 2017 to 2018. Cold-tolerance of IRG was significant different between varieties(p<0.05). Overwinter rate of domestic variety of IRG was higher than that of foreign variety(p<0.05). Among early-maturing varieties, overwinter rate of Kowinearly was highest as 68% that was 33% higher than that of Florida 80. Among middle-maturing varieties, overwinter rate of Kowinmaster was highest as 70% that was 28% higher than that of Tam 90. DM yield of IRG was significant different between varieties(p<0.05). Among early-maturing varieties, DM yield of Kowinearly and Greenfarm 2 was about 3 to 3.5 ton/ha more than that of Florida 80. Among middle-maturing varieties, DM yield of Kowinmaster was about 2ton/ha more than that of winter-hawk or Tam 90. There is a direct correlation between forage productivity and cold-tolerance of IRG variety(p<0.01). These results suggested that choice of early- or middle-maturing variety with cold-tolerant is more important for increasing the forage productivity of IRG If harvesting for roughage have to be finished in the middle ten days of May in middle region of Korea.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.1
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• pp.37-47
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• 2023

The black cutworm, Agrotis ipsilon (Hufnagel), is an important crop pest worldwide that feeds more than 80 plant species including cabbage, potato, maize, wheat and bean, and this moth is a typical pest attacking underground parts of crops. It has been known in farm booklets that the larvae of A. ipsilon overwinter in the soil in Korea, but no definitive data exist yet. This study was conducted to evaluate that the specific appearance time of A. ipsilon observed actually in the field could be explained when we assumed that this pest overwinters in a form of larvae or pupae. Degree day-based phenology models were applied for tracking forward or backward to find the predicted developmental stage which developed at a specific stage found in the field. As a result of the analysis, it was confirmed that an initial population could be established in a group that does not overwinter as larvae or pupae in Korea. In other words, the appearance of adults in early March to April could not be explained by the presence of domestic overwintering populations. Populations that overwinter as larvae or pupae in Korea were able to emerge as adults in June to July at the earliest. Therefore, the group of adults appearing in early spring is highly likely to be a population that migrated from outside Korea. Taken together, it was estimated that the colony of A. ipsilon in Korea would be formed by a mixture of a migrant population through long-distance migration and a overwintering population.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.70.1-70
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• 2002

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.175-176
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• 2002

Rice blast, caused by Pyricularia oryzae (P. oryzae), is generally considered to be the most serious fungal disease of rice by its widespread distribution and destructiveness (Manandhar et al., 1998). The pathogenic fungus directly penetrates into the rice plant from a cellular structure called an appressorium that is formed at the tip of the germ tube. And the fungus can attack any aerial part of the rice plant, including seeds, in which the fungus may overwinter for several years. (omitted)

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.251-251
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• 2017

This study was performed to select the soil covering materials for winter safety of Cynanchum wilfordii Hemsley and to investigate the effect on the growth after overwinter. Soil covering materials such as vinyl, rice straw, lagging cover, vinyl+lagging cover, and non-covering were investigated how effect on overwintering rate, growth and yield of Cynanchum wilfordii Hemsley. In changes of soil temperature according to the soil covering materials, non-covering treatment was recorded the highest to $26.7^{\circ}C$, and lagging cover and rice straw showed little change of soil temperature with 9.2 and $9.3^{\circ}C$, respectively. Regrowth rates of early growth after overwinter were lowered in the order as rice straw > vinly+lagging cover > lagging cover > vinyl > non-covering. From the above-ground growth by soil covering materials, vine length showed similar growth in all treatments except vinyl covering and stem diameter exhibited the thicker pattern in vinyl and lagging cover, and there was no significant difference among treatments in number of branch. Flowering period is recorded July 30 in all treatments and ripening period is October 16. Yield of seed production is showed the best in vinyl+lagging cover with $25g/m^2$. Root weight and root length for subterranean growth showed no significant differences among all treatments. Yield is produced the highest in vinyl+lagging cover with 433kg/10a and the next to lagging cover with 431kg/10a. In comparison with incomes, lagging cover earned to 9,882 thousand won/10a, showed the effect on income enlargement to 21%, compare to that of the non-covering.

• Korean Journal of Veterinary Service
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• v.38 no.1
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• pp.57-59
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• 2015

This study was carried out to investigate the Sacbrood virus (SBV) of Korean native honeybees causing serious damage in Jeonbuk area. Korean native honeybees completing the after overwinter 60 farms and March to April active phase adult bees and larvae 52 farms were collected from farms in 7 counties. Active phase of the adult bees 39 (75.0%) and larvae 24 (46.2%) farms was infected with SBV in 52 farms. This result indicate that SBV was the highest in Imsil-gun than other areas.

• Animal cells and systems
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• v.7 no.2
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• pp.111-117
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• 2003

Ecological aspects of Cryptocercus kyebangensis life history were investigated via laboratory rearing and field observations. The number of antennal segments and head width were used to classify the first four instars. The results, which combine both the field collection and the laboratory rearing, indicate that eleven instars occur in C. kyebangensis. It supports the proposal on the number of instars of Park and Choe (2003c) based on field collections. A total of 388 nymps from 13 colonies were collected prior to winter to investigate overwintering stages. Of them,4％ (n = 17) were the second instars, 57％ (n = 220) were the third instars, and 39％ (n = 151) were the fourth instars, respectively. Thus, most of them overwinter in the third or fourth instars. The results indicate that young nymphs of C. kyebangensis have to reach at least 3rd or 4th instar to survive low temperature environment of winter. According to seasonal dynamics of populations, C. kyebangensis reaches adulthood in the summer of the fourth or fifth year (4-5 yr span) after their birth.

• 한국약용작물학회:학술대회논문집
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• 2009.05a
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• pp.151-152
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• 2009