• Journal of Environmental Science International
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• v.26 no.1
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• pp.47-54
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• 2017

We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. This study aimed to understand how C. suppressalis damages crops and to utilize this basic data for the establishment of environment-friendly control methods like pheromone traps. This study surveyed the changes in occurrence patterns of C. suppressalis, biological characteristics of overwintering larvae, and the efficacy of different types of pheromone traps the years. We found similar occurrence patterns of C. suppressalis in different crops. In addition, occurrence time of the first generation was advanced. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. It was confirmed that larvae of C. suppressalis generally prefer the lower part of the stems of Miscanthus. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. However, it is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The major Miscanthus fields are generally located in the areas protected for sources of drinking water, owing to which spraying of chemical pesticides is very limited. The results of this study provide important inputs for the development of environment-friendly control methods.

• Korean journal of applied entomology
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• v.3
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• pp.41-44
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• 1964

1. This experiment was planned to compare the effectiveness of Diazinon granular and gammadol dust with the low toxic organophosphorus insecticides applied on the water-surface for the control of the rice stem borer, Chilo suppressalis Walker, in the 2 nd generation and to determine the proper timing of those insecticidal applications at Suwon, Korea, in 1964. 2. The hatching larvae from the eggs were inoculated on the rice plants in pots and insecticides were applied on the water-surface of pots at a given day intervals. The dose of insecticides used per pot was calculated from the 120g. as a actual ingredient per 10 a. The number of living larvae was observed at the 20 days later from the inoculation (as shown in Table 1.). 3. As shown in Table 2 and 3, there was highly significance between the chemicals and L.S.D. was 24.22. The best effectiveness was Diazinon granular and 2nd was gamma-dol dust. The organophosphorus emulsion concentrations used in this experiment were less effective than two other insecticides. Although there were some suspicious results according to the day intervals inoculated, the order of effectiveness was Diazinon>gamma-dol>Sumithion>EM>EPN> Cidial as the total moan. 4, As shown in Table 2 and 3, there was no significance between the timing of insecticidal applications, but, m the whole, Diazinon granular was most effective at a given day intervals in this experiment and gamma-dol also was effective at the day Plot inoculated. The proper timing of EPN, EM, and Cidial seemed to be at e day plot inoculated and that of Sumithion at the day plot before inoculation.

• Korean journal of applied entomology
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• v.1
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• pp.51-53
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• 1962

1. 본시험은 이화곤충방제에 유효하다고 인정된 신살충제를 선정하여 이화곤충에 대한 살충효과의 재확인 및 살포적기를 구명코저 시행하였다. 2. 제일화기에 있어서 Diazinon, Lebaycild, Endrin 및 Folidol은 부화 14일전 처리로서도 부화유충의 식입제로서 유효하였고, 부화유충 식입후일처리구에 있어서도 무처리구에 비하여 유효하였다. 3. 제2화기에 있어 부화 21일전 처리구의 유효성은 Detron=Folidol>$\gamma$-dol>Endrin>Dimecron의 순이었다. 그리고 부화 14일 및 17일전과 부화 2일 및 7일후 처리에 있어서도 $\gamma-dol$을 제한 다음 약제들은 고도의 유효성을 나타내었다. 4. 그러나 약제처리시기 사이에는 유의성이 없었다. 5. 본시험은 1회의 시험성적임으로 동일시험이 수회반복되어 살충효과 및 살포적기가 완전히 구명되었으면 한다.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.536-542
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• 1992

Control effects of carbofuran soil incorporation just before transplanting on the early occur-ring rice insect pests were studied in the rice field. Also, its residual effects on the brown planthopper (BPH) were studied by pot experiments. Carbofurn soil incorporation in late May was much more effective in controlling the early occurring rice insect pests such as small brown planthopper, green leafhopper and rice stem borer than carbofuran broadcasting or diazinon (3G) + BPMC (50% EC) treatment in mid June. Residual effects of carbofuran soil incorportaion on the female adult BPH decreased ca. a half one month after treatment. However, its residual effects on the next generation of the BPH lasted much longer; control effects on the next generation were above 90 and 70% on 37 and 46 days after treatment, respectively. From these results, it is thought that carbofuran soil incorporation just before rice transplanting can be a good control method to the early occurring rice insect pests and the brown planthopper immigrating during June. Also, it can suppress immigrating BPH popula¬tion moderately in early July.

• Korean journal of applied entomology
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• v.11 no.1
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• pp.25-30
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• 1972

Five to seven day old pupae were irradiated with gamma rays, the mating ability, and competability of the irradiated males were examined. The results obtained are summarized as follows: 1. There is no difference in percentage of males that mated, nor in the maximum number of matings of the males, when individual matings were made, and fresh females were provided every day for his life time. 2. The average days for the first mating of the emerged were 1.5 days for the control, and 2.4 days for the males irradiated with 25 and 30 Krad. The average days between first and second mating were 3.0 days for the irradiated males, and 1.3 days for the control. 3. The average matings of a male were 1.2 and 2.5 times when 5 and 10 females were provided to a normal male respectively. No significant different in average numbers of mated female per male were observed between the normal and irradiated males. 4. To test the mating competitiveness of the irradiated and normal males (1:0, 1:1, 2:1, 1:2, 5:1, 1:5, 0:1) were confined together with five virgin females. The greatest reduction in hatching percentage was found with 5 : 1 : 1 (30 Krad) where $26.6\%$ was hatched.5, The results showed that the irradiated males were not fully competitive with normal males, but if the reduced number of eggs produced by the female mated with irradiated male is considered, it might be used sterile male techniques in rice stem borer control.

• The Korean Journal of Mycology
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• v.27 no.3 s.90
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• pp.206-207
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• 1999

Hirsutella subulata (Hyphomycetes) was observed for the first time on diseased larvae of Chilo suppressalis in Korea. This fungus formed slender and slightly attenuated synnemata consisting of closely bound, longitudinal hyphae on the insect larvae. Typical characteristics of this species are ellipsoid or broadly obovoid phialides with slender, needle-like necks and asymmetric conidia. It is very similar to H. barberi but can be distinguished by its asymmetrical conidia.

• Korean journal of applied entomology
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• v.62 no.4
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• pp.227-243
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• 2023

The Asiatic pink stem borer, Sesamia inferens (Walker, 1856) (Lepidoptera: Noctuidae) is a pest that attacks rice stems. In this study, we estimated the annual generation of insect in several regions of the Republic of Korea. Adult trapping using a sex pheromone trap detected the occurrence of S. inferens adults in the three northernmost areas around 38° latitude and showed that the insect inhabits all of Korea. In most areas investigated, the seasons of the adult generations estimated using the single-sine degree-day model did not deviate from the corresponding observed seasons of adult occurrence. We estimated that the overwintering larvae hypothetically-estimated using the model could be originated from the last generation of adults. When larvae collected in paddy fields during the autumn season in a few middle and southern areas were reared at 25℃, ca. 70% of pupae did not show additional larval molting before their pupation. All larvae collected in early March in a southern area (Goseong, Gyeongsangnam-do) pupated without additional larval molting when reared at 25℃. Based on these results, we presumed that S. inferens could overwinter as mainly the last instar larval stage in the area. Taken together, we conclude that S. inferens primarily has two generations per year in areas around 38° latitude, and three generations in the areas between 35.3° and 37.3° latitude. In addition, approximately 35% of insects captured by the sex pheromone trap were species other than S. inferens, as determined by analyzing the nucleotide sequences of the cytochrome c oxidase 1 gene. These species were not morphologically misidentified as S. inferens.

• Korean journal of applied entomology
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• v.4
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• pp.67-74
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• 1965

The work on the 'Studies of radiosensitivity' in Korea has been initiated since 1959 by the author at various institutions in home and foreign countries, and more than 20000 of plant materials in 73 varieties and 41 kinds are treated under varied conditions for the studies of radiosensitivity in plants. However, a study of the susceptibility to radiation in insect pests as well as their biological effects has not been previously reported in this country. During the year of 1964 and 1965, near 50000 of insects at the stages of adult, egg, larva and pupa in 14 different kinds are irradiated under acute X and gamma rays to investigate the behavior of growth and lethality after irradiation, and thrir general tolerances to radiations are compared by the kind of insects, stage of growth, radiation sources and exposured dosages. Through the experiments, it is shown that the lethality in most of insects are high as several kilo roentgens above and no significant effects on pupation. emergence, and oviposition in the treated generation at the dose of 3 Kr. below, but in the following generation , the rice stem borer for instance, no oviposition or decreased laying is observed from the dosages at 3 Kr. to 1 Kr., and the hatching was possible from 1.5 Kr. below of irradiated larvae although laying and hatching are seemed in normal. In general, the lethal dose $50\%$ of tested infect materials at the larval stage can he classified some what 60-80 Kr. for Pine caterpillar, Fall webworm, Camphor silk moth and their relatives, at 40-60 Kr. for Gypsy moth, Monley prominent and some relatives and at 20-30 Kr. for House fly, Rice weevil, Pine sawfly etc. Plant parasitic nematodes such as Hirschmannia and Paratylenchus shown very high resistance to radiation and the LD-50 is observed from 100 Kr. or above. A concept to evaluate the radiosensitivity in insects by taxological family line as a practical measure is not answerable yet, but it ran he solved within the near future through the continuing experiments.

• Korean journal of applied entomology
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• v.25 no.1 s.66
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• pp.37-40
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• 1986

We surveyed the IRRI farm to determine the extent of parasitization of yellow stemborer egg masses. The egg masses were randomly collected at weekly intervals from July to October 1984 from rice fields, 15-20 days after transplanting, and brought to the laboratory for collection of emerging parasites. Three species of hymenopterous parasitoids-Tetrasticus schoenobii, Telenomus rowani, and Trichogramma japonicum-were found from 700 egg masses. We introduced a method to calculate percent parasitism as based on parasite biology and behaviour. Among the three species, the combination of T. rowani and T. japonicum was the highest multiparasitization of yellow stem borer egg masses, and T. rowani, a solitary parasite had the highest number based on immature and adult stages counted. However, T. schoenobii may be the most efficient parasite because two to four host eggs are needed to complete the larval period, and it took $10{\sim}14$ days for one generation.

• Korean Journal of Food Science and Technology
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• v.10 no.3
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• pp.306-312
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• 1978

Residue levels of an organochlorine insecticide, BHC, were determined for brown rice samples produced in Korea by collection and field experiments to obtain the following results. 1) Residue levels of total BHC in 112 samples (an Indica type variety Tongil) produced in 1976 and collected from 9 provinces in proportion to the production level of rice ranged from 0.0010 to 0.0762 ppm, the average being 0.0061 ppm. 2) The residue levels in samples from Jeonbook, Kyongnam and Choongnam provinces were higher than the average for whole samples. BHC isomers were found in the order of ${\alpha}>{\gamma}>{\beta}>{\delta}$ isomers, and the detection frequency by range were 89.3% below 0.01 ppm, 9.8% for $0.01{\sim}0.05{\;}ppm$ and 0.9% for $0.05{\sim}0.10{\;}ppm$. 3) In field experiments according to conventional agronomical practices, the brown rice samples after spraying of BHC at the first generation time of rice stem borer (4 kg of 6% granular formulation/10 a paddy field) showed a little higher residue level than control samples, but not more than 0.035 ppm, whereas samples after spraying at the second generation time (3 kg/10 a) contained in the range of $0.04{\sim}0.19\;ppm$.