• Title/Summary/Keyword: Population suppression

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Biological Control Strategy of Uzi Fly in Sericulture

  • Singh, R.N.;Saratchandra, Beera
    • International Journal of Industrial Entomology and Biomaterials
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    • v.6 no.2
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    • pp.125-132
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    • 2003
  • Uzi fly (Exorista bombycis Louis) is one of the major larval endo-parasitoid of silkworm (Bombyx mori). It causes extensive damage to sericulture industry. The application of synthetic organic pesticides has tremendous impact on minimizing pest population but their overuse and frequent misuse and high sensitivity towards the silkworms, has forced the entomologists to search for alternatives to chemical control, which is safe to silkworm, environment and farm workers. Biological control continues to offer exciting possibilities for the control of fly pest population. It is environmentally safe alternative to chemical control and offering a long-term protection. Several potential hymenopteran parasitoids have been screened. Among successful natural enemies, Nesolynx thymus, Trichomalopsis apanteloctena, Trichopria sp., Brachymeria lasus, Pediobius sp., Spalangia sp., Spilomicrus karnatakensis and Dhirhinus sp. are important. It is essential to predict accurately the efficacy of these natural enemies in a new habitat prior to its introduction. The important desirable attributes of these potential parasitoids viz., host searching capacity, specificity, power of increase and fitness and adaptability of the parasitoid in new environment has been recorded. Results of the host parasitoid interaction indicate that the aging of the host function as a factor that influence the host finding efficiency of the parasitoid. It is highly scored with 15-20 hrs old pupa of the host. However, aging of the parasitoid does not significantly affect it. The sex ratio is female biased which is advantageous from biological control point of view, Biological suppression methods involving conservation and utilization of natural enemies have been discussed in detail.

Loss of Expression of Cyclin D2 by Aberrant DNA Methylation: a Potential Biomarker in Vietnamese Breast Cancer Patients

  • Truong, Phuong Kim;Lao, Thuan Duc;Doan, Thao Phuong Thi;Huyen Le, Thuy Ai
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.6
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    • pp.2209-2213
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    • 2015
  • DNA methylation of tumor suppressor gene promoters is the most frequent phenomenon leading to inactivation of function, consequently driving malignant cell transformation. Cyclin D2 is implicated in tumor suppression. In our study, we carried out the MSP assay to evaluation the methylation status at CpG islands in the cyclin D2 promoter in breast cancer cases from the Vietnamese population. The results showed that the frequency of methylation reached 62.1% (59 of 95 breast cancer tumors), but was low in non-cancer specimens at 10% (2 of 20 non-cancer specimens). Additionally, with an RR (relative risk) and OR (odd ratios) of 6.21 and 14.8, DNA hypermethylation of cyclin D2 increased the possibility of malignant transformation. Our results confirmed the cyclin D2 hypermethylation could be used as the potential biomarker which could be applied in prognosis and early diagnosis of Vietnamese breast cancer patients.

The Eclogy of the Pine Needle Gall Midge (Thecodiplosis japonensis Uchida et Inouye) ana Its Control Strategies (솔잎혹파리의 생태와 방제전략)

  • Hyun Jai Sun
    • Korean journal of applied entomology
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    • v.21 no.3 s.52
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    • pp.163-166
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    • 1982
  • The pine needle gall midge, Therodiplosis japonensis Uchida et Inouye, is the most important insect pest. It requires two different habitats for the development; on trees and under the ground. The habitat specific mortality rates ere $30\~40\%,\;and\;50\~60\%$ for the respective habitats. The key developmental stage is the prepupa, and the key mortality factor is the moisture contents of the soil and its variability. Since the insect is an exotic, the population status is the periphery and in the source of infestation are considerably different. Such a difference in habitats and the population status of the insect should be considered in relation to suppression of the insect. The control strategies should be directional and rational based on the reality of the pest status. There have been substantial information on the control methods of the pine needle gall midge, and each control method has an important place, but none has always provided a satisfactory solution to the many problems associated by this insect. These methods should be applied to a system based on the ecology of the insect. There should be continued support for directed effort on the development of operational management systems for the insect: specifically, estmation of the critical economic injury level, and of the absolute density of the insect.

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Suppression of Indian Meal Moth (Lepidoptera : Pyralidae) by Iterative Mass Release of Bracon hebetor (Hymenoptera : Braconidae) in Wheat Elevators (대형 엘리베이터에서 Bracon hebetor (벌목: 좀벌과)의 반복 방사에 의한 화랑곡나방 (나비목 : 명나방과)의 방제 효과)

  • Na, Ja-Hyun;Chun, Yong-Shik;Ryoo, Mun-Il
    • Korean journal of applied entomology
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    • v.44 no.3 s.140
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    • pp.237-241
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    • 2005
  • Biological control of Indian meat moth (Plodia interpunctella ($H\"{u}bner$)) by iterative mass release of its larval parasitoid, Bracon hebetor Say, was tested in a large wheat elevator (diameter 8 m, height 41 m) containing 6,000 t of wheat. Adult parasitoids were released seven times from July 23 to September 3, 2002. The number of parasitoid adults per release time varied from 3,000 to 10,000 so that the total number released was 50,000. The moth population density in the parasitoid-released elevator was maintained at a level of ${\approx}30%$ compared to the moth population in untreated elevators.

Culturing Simpler and Bacterial Wilt Suppressive Microbial Communities from Tomato Rhizosphere

  • Roy, Nazish;Choi, Kihyuck;Khan, Raees;Lee, Seon-Woo
    • The Plant Pathology Journal
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    • v.35 no.4
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    • pp.362-371
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    • 2019
  • Plant phenotype is affected by a community of associated microorganisms which requires dissection of the functional fraction. In this study, we aimed to culture the functionally active fraction of an upland soil microbiome, which can suppress tomato bacterial wilt. The microbiome fraction (MF) from the rhizosphere of Hawaii 7996 treated with an upland soil or forest soil MF was successively cultured in a designed modified M9 (MM9) medium partially mimicking the nutrient composition of tomato root exudates. Bacterial cells were harvested to amplify V3 and V4 regions of 16S rRNA gene for QIIME based sequence analysis and were also treated to Hawaii 7996 prior to Ralstonia solanacearum inoculation. The disease progress indicated that the upland MM9 $1^{st}$ transfer suppressed the bacterial wilt. Community analysis revealed that species richness was declined by successive cultivation of the MF. The upland MM9 $1^{st}$ transfer harbored population of phylum Proteobacteria (98.12%), Bacteriodetes (0.69%), Firmicutes (0.51%), Actinobacteria (0.08%), unidentified (0.54%), Cyanobacteria (0.01%), FBP (0.001%), OD1 (0.001%), Acidobacteria (0.005%). The family Enterobacteriaceae of Proteobacteria was the dominant member (86.76%) of the total population of which genus Enterobacter composed 86.76% making it a potential candidate to suppress bacterial wilt. The results suggest that this mixed culture approach is feasible to harvest microorganisms which may function as biocontrol agents.

Trunk Injection of Citrus Trees with a Polymeric Nanobactericide Reduces Huanglongbing Severity Caused by Candidatus Liberibacter asiaticus

  • Ramiro Guerrero-Santos;Gabriela Cabrales-Orona;John Paul Delano-Frier;Judith Cabello-Romero;Jose Roman Torres-Lubian;Jose Humberto Valenzuela-Soto
    • The Plant Pathology Journal
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    • v.40 no.2
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    • pp.139-150
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    • 2024
  • Huanglongbing (HLB) is a disease caused by the phloem-limited Candidatus Liberibacter asiaticus (CLas) that affects the citrus industry worldwide. To date, only indirect strategies have been implemented to eradicate HLB. Included among these is the population control of the psyllid vector (Diaphorina citri), which usually provides inconsistent results. Even though strategies for direct CLas suppression seem a priori more promising, only a handful of reports have been focused on a confrontation of the pathogen. Recent developments in polymer chemistry have allowed the design of polycationic self-assembled block copolymers with outstanding antibacterial capabilities. Here, we report the use of polymeric nano-sized bactericide particles (PNB) to control CLas directly in the phloem vasculature. The field experiments were performed in Rioverde, San Luis Potosí, and is one of the most important citrusproducing regions in Mexico. An average 52% reduction in the bacterial population was produced when PNB was injected directly into the trunk of 20 infected trees, although, in some cases, reduction levels reached 97%. These results position PNB as a novel and promising nanotechnological tool for citrus crop protection against CLas and other related pathogens.

Effect of Double-Cropping Systems on Nematode Population in Plastic Film House Soils of Oriental Melon Cultivation (이모작에 따른 참외 재배 비닐하우스 토양의 선충밀도 변화)

  • Byeon, Il-Su;Suh, Sun-Young;Lee, Yong-Se;Chung, Jong-Bae
    • Korean Journal of Environmental Agriculture
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    • v.33 no.1
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    • pp.17-23
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    • 2014
  • BACKGROUND: Crop rotation is often used as a solution to eradicate nematodes in soils used in plastic film houses for long-term cultivation of oriental melon. However, it is not clear if the double-cropping is effective in reducing nematode populations in soils. METHODS AND RESULTS: Nematode population in plastic film house soil was measured during oriental melon cultivation from April to July in short term crop rotation systems of oriental melon. Double-cropping of chinese cabbage in open-field for 3-4 months following oriental melon in plastic film houses could not prevent the build-up of high population density of nematodes. However, double-cropping of dropwort in flooded soil for 3-4 months following oriental melon in plastic film houses could effectively reduce the nematode population during the successive year of oriental melon cultivation. The reduced nematode population in soils of oriental melon-dropwort double-cropping system was continued until the mid season of progressive year oriental melon cultivation. Application of nematicide to soil before growing oriental melon in the oriental melon-dropwort double-cropping was very effective in preventing the build-up of high population density of nematode in plastic film house soils. CONCLUSION: Short-term introduction of crop rotation was not effective in suppression of high population density of nematodes in plastic film house soils of long-term year-to-year production of oriental melon. For securing the soil productivity and sustainability of plastic film house, various physical, chemical, and agronomic practices should be properly combined together.

Effects of Chungganhaewooltang on Serum Levels of Histamine and Corticosterone and Immune Response after Immobilization-Stress or Cold-Stress in Mice (청간해울탕(淸肝解鬱湯)이 생취에 Immobilization-Stress 및 Cold-Stress 부하후(負荷後) 혈중(血中)Histamine과 Corticosterone 함량(含量) 및 면역능(免疫能)에 미치는 영향(影響))

  • Kang, Bok-Hwan;Jung, Woo-Suk;Kim, Song-Baeg;Yoo, Sim-Keun
    • The Journal of Korean Obstetrics and Gynecology
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    • v.18 no.4
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    • pp.85-105
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    • 2005
  • Purpose : Investigate the effects of Chungganhaewooltang(CHT) on immobilization-stress or cold-stress in C576BL/6J mice. Methods : Male C57BL/6J 30 mice of weighting 18${\pm}$2g, were divided into sixs groups including the immobilization-stress group(5heads), after immobilization-stress CHT oral administration(500mg/kg) groups(5heads), cold-stress group(5heads) and after cold-stress CHT oral administration(500mg/kg) groups(5heads). then we observed changes in the serum histamine and corticosterone level and changes immune system Results : Immobilization-stress or cold-stress increased the serum level of histamine and corticosterone. CHT decreased the serum level of histamine and corticosterone increased by cold-stress. CHT inhibited the release of histamine from mast cells at the concentration of 0.1 mg/ml. In addition, immobilization-stress or cold-stress decreased the cell viability of murine thymocytes and splenocytes. CHT increased the cell viability of thymocytes decreased by immobilization-stress or cold-stress, but did not affect the cell viability of splenocytes decreased by immobilization-stress or cold-stress. Also immobilization-stress or cold-stress increased DNA fragmentation of thymocytes and splenocytes. CHT decreased DNA fragmentation of thymocytes increased by immobilization-stress or cold-stress, but did not affect DNA fragmentation of splenocytes increased by immobilization-stress or cold-stress. Immobilization-stress increased the population of thymic $CD4^+$ cells. CHT decreased the population of thymic $CD4^+$ cells increased by immobolization-stress. Immobilization-stress or cold-stress decreased the population of $B220^+$ cells and increased the population of $thy1^+$ cells. CHT decreased the population of $thy1^+$ cells increased by immobilization-stress or cold-stress. Immobilization-stress or cold-stress increased the population of splenic $CD4^+$ cells and $CD8^+$ cells. CHT decreased the population of splenic $CD4^+$ cells increased by immobolization-stress or cold-stress. Immobilization-stress or cold-stress decreased the production of ${\gamma}-interferon$(IFN) interleukin(IL)-2 and IL-4. CHT enhanced the production of ${\gamma}-IFN$ decreased by immobilization-stress or cold-stress but did not affect the production of IL-2 and IL-4 decreased by immobilization-stress or cold-stress. Furthermore, Immobilization- stress or cold-stress decreased the phagocytic activity of peritoneal macrophages and the production of nitric oxide. CHT enhanced the phagocytic activity and nitric oxide production decreased by cold-stress. Conclusion : CHT may be useful for the prevention and treatment of stress via suppression of serum histamine and corticosterone level and enhancement of immune response.

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False Seedbed Weed Control under Different Preparation Date and Method in Organic Corn Field (옥수수밭 예방적 잡초방제를 위한 가묘상 처리 시기)

  • Lee, Byung-Mo;Jo, Jeong-Rae;An, Nan-Hee;Ok, Jung-Heun;Kim, Seog-Cheol
    • Weed & Turfgrass Science
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    • v.3 no.4
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    • pp.299-304
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    • 2014
  • Effects of false seedbed procedures in organic corn field were evaluated as affected by preparation date and method. False seedbed was prepared at May 7, 14, 21, 28 and June 5 with shallow tillage or flame weeding. Weed suppression rate of each treatment was evaluated 3 weeks after sowing. Optimal false seedbed preparation time was between end of May and early in June. Weed suppression rate of early false seedbed preparation was quiet low. Flaming weed treatment was better than shallow tillage. Weed suppression rate by the second treatment was increased approximately 30-60% compared to $1^{st}$ treatment. Weed suppression rate at 3 weeks after sowing was 70-90% by the second false seedbed preparation. The results showed that the false seedbed technique between end of May and early in June preparation has some potential weed control to reduce weed population during crop growth. Therefore late planting time crop such as corn, sorghum and soybean would be possible to apply false seedbed for organic weed control.

The Meaning of P50 Suppression : Interaction of Gamma and Alpha Waves

  • Lee, Kyungjun;Kang, Ung Gu
    • Korean Journal of Biological Psychiatry
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    • v.21 no.4
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    • pp.168-174
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    • 2014
  • Objectives Sensory gating dysfunctions in patients with schizophrenia and bipolar disorder have been investigated through two similar methods ; P50 suppression and prepulse inhibition paradigms. However, recent studies have demonstrated that the two measures are not correlated but rather constitute as distinct neural processes. Recent studies adopting spectral frequency analysis suggest that P50 suppression reflects the interaction between gamma and other frequency bands. The aim of the present study is to investigate which frequency component shows more significant interaction with gamma band. Methods A total of 108 mood disorder patients and 36 normal subjects were included in the study. The P50 responses to conditioning and test stimuli with an intra-pair interval of 500 msec were measured in the study population. According to P50 ratio (amplitude to the test stimulus/amplitude to the conditioning stimulus), the subjects with P50 ratio less than 0.2 were defined as suppressed group (SG) ; non-suppressed group (NSG) consisted of P50 ratio more than 0.8. Thirty-five and 25 subjects were included in SG and NSG, respectively. Point-to-point correlation coefficients (PPCCs) of both groups were calculated between two time-windows : the first window (S1) was defined as the time-window of one hundred millisecond after the conditioning auditory stimulus and the second window (S2) was defined as the time-window of 100 msec after the test auditory stimulus. Spectral frequency analysis was performed to investigate which frequency band results in the difference of PPCC between SG and NSG. Results Significant reduction of PPCC between S1 and S2 was observed in the SG (Pearson's r = 0.24), compared to PPCC of the NSG (r = 0.58, p < 0.05). In spectral frequency analysis, gamma band showed "phase-reset" and similar responses after the two auditory stimuli in suppressed and non-suppressed group. However in the case of alpha band, comparison showed significantly low PPCC in SG (r = -0.14) compared to NSG (r = 0.36, p < 0.05). This may be reflecting "phase-out" of alpha band against gamma band at approximately 50 msecs after the test stimulus in the SG. Conclusions Our study suggests that normal P50 suppression is caused by phase-out of alpha band against gamma band after the second auditory stimulus. Thus it is demonstrated that normal sensory gating process is constituted with attenuated alpha power, superimposed on consistent gamma response. Implications of preserved gamma and decreased alpha band in sensory gating function are discussed.