• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.334-341
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• 1997

Artificial precipitation test with sprinkler system was carried out to develop the collection method of arboreal larvae(proctotrupoid wasps) of pine needle gall midge for biological control in 1995. Effects of larvae falling on each amount of precipitation, season of precipitation and time of precipitation of a day following artificial precipitation were examined during the period of larvae falling season. The results obtained were summarized as follows; 1. Artificial precipitation with sprinkler system was highly effective for collection of pine needle gall midge larvae and the most suitable amount of precipitation was 5.3-9.4mm; application amount and hours of water were $8,000-16.000{\ell}$ and 180-360 minutes, respectively. 2. The most effective period of larvae collection for artificial precipitation was approximately 20 days, from early through mid November, and larvae falling was 93.4% of the total number of larvae collection during this period. 3. Larvae falling from the tree crown was not affected by the artificial precipitation for the precipitation hour intervals in a day. 4. The percentage of parasitism of collected larvae of pine needle gall midge in November exceeded that of December but was not significantly different between two seasons. 5. Artificial precipitation of sprinkler system was effective in reducing 34% of gall formation after one year at collected sites of pine needle gall midge larvae. 6. The collection method of larvae following artificial precipitation was effective in reducing the expenses by 14-50% than that of collection method of infested needles.

• Journal of Korean Society of Forest Science
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• v.5 no.1
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• pp.22-26
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• 1966

As a series of studies on the behaviour of Pine gallmidge (Theccdiplosis japonensis Uehida ei Inoaye), the season of the larval hibernation in winter as well as the season of the attack of adults on pine needles in the vicinity of Seoul were observed, and following results were obtained. 1. The larvae get out of the galls and fall into the ground for the hibernation commencing from the end of September and finishing by the end of January of the next year. 2. About 76% of the whole larvae fell down during the month of November. 3. The frequency and the duration of raining mainly influenced the larval falling into the ground but temperature, humidity and the quantity of rainfall was not likely influence upon it. 4. As many as 47,000 larvae were counted per 1.5 square meter of the ground under the crown of the damaged trees. 5. When pine needles were isolated by fine linen-net-bag to keep the needles from the oviposition of the adults of the insect, at six different season; -i.e. 30th, May, 6th, 10th, 15th, 25th, and 30th June, the percentages of the damage were 80%, 50%, 36%, 19%, 20% and 1% respectively, while the damage of the control was 91%.

• Ocean and Polar Research
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• v.41 no.4
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• pp.233-250
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• 2019

A re-assessment of the age structure of the population of the Antarctic icefish Pseudochaenichthys georgianus based on body length data covering the years 1976-2009 and including larvae and postlarvae collected in 1989 and 1990 allowed us to define age groups 0, I, and II as containing fish with respective body lengths of 6-9 cm, 15-27 cm and 27-39 cm. Age at maturity (first spawning) was found to occur in age group III at body lengths that have been falling from 50.1 cm in 1979 to 45.4 cm in 1992. Considering postlarvae together with adult fish, the v. Bertalanffy growth curve parameters were determined as L_∞ = 60.62 cm, k = 0.4, t₀ = 0.25. Although the reasons for a maturity at shorter body lengths is not fully understood a host of environmental factors like increasing water temperatures and possibly changes in currents, interspecific competition, food availability, etc. are likely to be involved. Global warming (and not primarily overfishing) is likely to have been responsible for the disappearance of larger fish in the surface waters of South Georgia since 1977, for virtually all commercial fishing stopped in the early 1990s. On the other hand, the appearance of numerous younger spawning individuals suggests that larvae do survive in the colder deeper water below 200 m. The biomass of Ps. georgianus oscillates with a 4-year periodicity in contrast to that of the coexisting icefish Chaenocephalus aceratus: the former with a lower biomass in warm years and a higher one in cold years. The biomass of the third species of icefish in the region, i.e. Champsocephalus gunnari, also oscillates, but with a longer periodicity than that involved in the biology of the other two and its biomass increases in contrast to the other two species. The result is that the biomass all three species considered together is rather stable.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.439-442
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• 1996

In this study, we tried to figure out the ecology of Masakimyia pustulae Yukawa et Sunose which attacts evergreen euonymus and results in scenic damage caused by early falling of leaves and may increase the susceptibility for anthrocnose. In addition, we tried to develope a method for the control of the insect to prevent spreading of the damage by use of insecticide. The results obtained from the study were as follows : 1. Masakimyia pustulae emerged from late April to late May at Chuncheon area. Average length of the adult insects was $1.88{\pm}0.43mm$, and the life span of them reached about 11 hours. The sex ratio of the insect was 56 : 44(female : male), and they ovipositied $90{\pm}28$ eggs. The shape of eggs was oval with average length $0.32{\pm}0.013mm$. The length of larvae averaged $1.64{\pm}0.25mm$ and started pupation from mid-March, which took about 40~50 days, although there was variance due to temperature variation in each spring. 2. The 3% powder of carbofuran treatment by burying $200g/m^3$ of the insecticide around the damaged tree during mid-March with additional burying about a week after pupation showed good result for the control of the insect, which resulted in more than 96.2% removal of the insects.