• Title/Summary/Keyword: agricultural insect pests

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Zoophthora phalloides Batko (Zygomycetes: Entomophthoraceae), a Fungal Parasite of the Aphid Dactynotus species in Korea (Dactynotus 진딧물의 국내 미기록 곤충병원성 곰팡이, Zoophthora phalloides에 관한 보고)

  • Yoon, Cheol-Sik;Sung, Gi-Ho;Lee, Seung-Hwan;Yun, Tae-Yu;Lee, Jeang-Oon
    • The Korean Journal of Mycology
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    • v.26 no.4 s.87
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    • pp.413-415
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    • 1998
  • An entomophthoraceous fungus, Zoophthora phalloides, was found in populations of the aphid Dactynotus species, at National Institute of Agricultural Science and Technology, and Jeonnam Provincial RDA during June, 1998. Occurrence of the fungus and aphid has never been recorded in Korea. Microscopic observations of this fungus are described, and illustrated. The fungus has sausage-shaped primary conidia with $28.98\;{\mu}m$ in length, and two types of secondary conidiophores. Our specimens exhibit closer relationship with the North American isolates than with the European isolates on the basis of conidial length described by other study.

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Improvement of Wuyiencin Biosynthesis in Streptomyces wuyiensis CK-15 by Identification of a Key Regulator, WysR

  • Liu, Yanyan;Ryu, Hojin;Ge, Beibei;Pan, Guohui;Sun, Lei;Park, Kyungseok;Zhang, Kecheng
    • Journal of Microbiology and Biotechnology
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    • v.24 no.12
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    • pp.1644-1653
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    • 2014
  • Wuyiencin is produced by Streptomyces ahygroscopicus var. wuyiensis CK-15 and is widely used as an antifungal agent in agriculture. Analysis of wuyiencin biosynthetic gene clusters reveals wysR, a member of the LAL-family of transcriptional regulatory genes. WysR consists of an N-terminal PAS domain and a LuxR family C-terminal helix-turn-helix motif. However, the roles of wysR in wuyiencin biosynthesis are largely unknown. In this study, we showed that inactivation of wysR resulted in the complete loss of wuyiencin production, which could be restored by complementation with a single copy of wysR. Furthermore, we successfully increased wuyiencin production to a significantly higher level by overexpression of wysR in S. wuyiensis CK-15. Quantitative real-time RT-PCR analysis showed that WysR regulates wuyiencin biosynthesis by modulating other putative regulatory genes. Thus, WysR was identified as an activator of wuyiencin biosynthesis, and overexpression of wysR gene proved to be an effective strategy for improving wuyiencin production.

Study of Major Insect Pests on Rice and Corn in Four Provinces in Red River Delta of Vietnam During 2018- 2022

  • Thuy Linh Pham;Ohseok Kwon
    • Proceedings of the National Institute of Ecology of the Republic of Korea
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    • v.5 no.1
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    • pp.21-27
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    • 2024
  • Harmful pet insects, if not controlled, can negatively affect people, plants and their surrounding environment. In Vietnam, all crops are regularly impacted by pest insects. In serious cases, crops can be totally destroyed by insect pests. Harmful insects that damage crops often grow fast and increase rapidly. Therefore, research on insects is crucial for managing pests, protecting crops, and forecasting pest situation in the following years. This study aimed to collect data regarding changes of pests on rice and corn as two main crops in four provinces in Red River Delta of Vietnam, including Thai Binh, Nam Dinh, Ha Nam, and Hung Yen, from 2018 to 2022. Primary data were collected from reports of government agencies and official statistics. Based on these data, this study evaluated changes of pest insects in five years, discussed reasons for such changes and response methods, and forecasted pest's behavior in the following years. Significant findings of this study include the fact that Vietnam has to face many difficulties to develop its agricultural sector. For insect management, an essential action is to do ground surveys to gather all related data including weather data, pesticide data, crop yield, and product quality. This information is meaningful for finding out causes of changes, understanding relationships between insects and surrounding factors, and predicting the situation in the following years.

Comparison of Environmental-Friendly and Chemical Spray Calendar for Controlling Diseases and Insect Pests of Strawberry during Nursery Seasons (딸기 육묘기 병해충 관리를 위한 친환경과 화학적 방제력 비교)

  • Nam, Myeong Hyeon;Kim, Hyun Sook;Kim, Tae Il;Lee, Eun Mo
    • Research in Plant Disease
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    • v.21 no.4
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    • pp.273-279
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    • 2015
  • Major diseases and insect pests in nursery season of strawberry were anthracnose, powdery mildew, Fusarium wilt, two-spotted spider mite, and aphids. Environmental-friendly and chemical application schedules can improve diseases and insect pests control with relatively fewer organic and chemical materials inputs compared with spray programs when it's occurred. Field experiments were performed in 2012 to 2013 according to calendar-based spray programs with environmental-friendly spray calendar (EFSC) and conventional chemical spray calendar (CSC) for controlling diseases and insect pests of strawberry plants cv, Seolhyang during the two nursery seasons. EFSC did reduce the incidence of diseases and insect pests as compared to the non-treated control. Incidence of anthracnose and powdery mildew by EFSC and CSC was similar in 2012 and 2013 seasons. In addition, occurrence of two-spotted spider mite in EFSC in 2013 was similar to those of CSC and was shown highly in early and mid-June both 2012 and 2013 seasons. Occurrence of aphid in EFSC was shown highly in early and mid-June both 2012 and 2013 seasons. These results suggest that EFSC program may be effective for controlling strawberry diseases and insect pests by using environmental-friendly organic materials.

Insect Pests and Their Natural Enemies in the Controlled Agricultural Farms (시설농업지에서의 해충과 천적의 발생상)

  • Seo, Mi-ja;Ahn, Soo-jeong;Park, Deok-kee;Youn, Young-nam
    • Korean Journal of Agricultural Science
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    • v.24 no.1
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    • pp.21-28
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    • 1997
  • For the investigation of occurrence of insect pests and their natural enemies, total number of 353 controlled agricultural farms were visited and surveyed. In the 73% of total controlled agricultural farms, 52 species insect pests were occurred. Among these pests, the western flower thrip (Frankliniella occidentalis), the two spotted spider mite (Tetranychus urticae), the greenhouse whitefly (Trialeurodes vaporariorum), the cotton aphid (Aphis gossypii) and the green peach aphid (Myzus persicae) were mainly occurred. On the other hand, small numbers of natural enemies were sustained in 40 controlled agricultural farms, which was 11% and 17% of visited farms and pest occurred farms, respectively. For the most part of collected natural enemies, there were included in Braconid, Coccinellid and Anthocorid, as 63, 20 and 8% of them, respectively.

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Expression and Synergistic Effect of Bacillus thuringiensis CrylAc in Lepidopteran Toxic Strain to Plutella xylostella

  • Kang, Joong-Nam;Roh, Jong-Yul;Shin, Sang-Chul;Ko, Sang-Hyun;Chung, Yeong-Jin;Kim, Yang-Su;Wang, Yong;Choi, Hee-Kyu;Li, Ming-Shun;Choi, Jae-Young;Je, Yeon-Ho
    • International Journal of Industrial Entomology and Biomaterials
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    • v.14 no.1
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    • pp.33-36
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    • 2007
  • To improve insecticidal activity of B. thuringiensis 2385-1 (Bt 2385-1), a recombinant plasmid, pHT1K-1Ac, was introduced into lepidopteran toxic Bt 2385-1 by electroporation. The presence of the recombinant plasmid in Bt 2385-1 after electroporation was confirmed by PCR. Bt 2385-1 transformant was named as Bt pHT1K-1Ac/2385-1 (1K-1Ac/2385-1). The 1K-1Ac/2385-1 transformant produced bipyramidal-shaped parasporal inclusion as like the wild-type strain, Bt 2385-1, and showed an 130 kDa band of Cry1Ac protein. The insecticidal activity of 1K-lAc/2385-1 against S. exigua was similar to that of Bt 2385-1 but the $LC_{50}$ value of transformant against P. xylostella was 1.8 times lower. Through these bioassay results, it was confirmed that toxicity of Bt 2385-1 transformant showed synergistic effect by introducing Cry1Ac. These results suggested that the multiple expressions of Cry proteins in a promising Bt strain may interact synergistically in insect midgut, resulting in increase of toxicity and expansion of host spectrum.

Insecticidal Activities of Aromatic Plant Extracts against Four Agricultural Insects

  • Kim, Soon-Il;Shin, Ook-Kyun;Song, Cheol;Cho, Kwang-Yun;Ahn, Young-Joon
    • Journal of Applied Biological Chemistry
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    • v.44 no.1
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    • pp.23-26
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    • 2001
  • The insecticidal activities of 30 aromatic plant extracts against four insect pests were examined by direct contact application. Against Nilaparvata lugens female adults, Myzus persicae female adults, and Plutella xylostella larvae, at 5,000 ppm, >90% mortality was achieved in the methanol extracts of the rhizomes from Cnidium officinale, Acorus gramineus, Acorus calamus var. angustatus and Curcuma Ionga, the whole plant from Agastache rugosa, the fruits from Illicium verum and Piper nigrum, and the flower bud from Eugenia caryophyllata as well as Cinnamomum camphora steam distillate. Against Spodoptera litura larvae, all test plant extracts were ineffective. The plants described merit further study as potential insect-control agents against insect pests.

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An Investigation and Evaluation of Insect Pests in Greenhouse Vegetables in Jeonbuk Province (전북지역 시설 채소류 작물별 해충 발생양상 및 종 동정)

  • Lim, Ju-Rak;Park, Sung-Hee;Moon, Hyung-Cheol;Kim, Ju;Choi, Dong-Chil;Hwang, Chang-Yeon;Lee, Kwan-Suk
    • Korean journal of applied entomology
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    • v.51 no.3
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    • pp.271-280
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    • 2012
  • Twenty-two families and 39 species of insect pests were surveyed on five families and 20 species of greenhouse vegetables in Jeonbuk province. The species of insect pests and the families of plants infested were seven families and 10 species on Chenophodiaceae, 16 families and 25 species on Brassicaceae, nine families and 10 species on Apiaceae, six families seven species on Liliaceae, and 13 families and 29 species on Compositae. Spodoptera exigua H$\ddot{u}$bner and Spodoptera litura Fabricius occurred on all vegetables. Additionally, Frankliniella intonsa Trybom, Trialeurodes vaporariorum Westwood, Myzus persicae Sulzer, and Phytomyza horticola Goureau occurred on all vegetables except Liliaceae(Allium tuberosum Rottl. and Allium fistulosum L.). Thirteen species of insect pests including Hymenia recurvalis Fabricius occurred only one vegetables, indicating that they were monophagous. The main insect pests of Chenophodiaceae were M. persicae, H. recurvalis, S. exigua and S. litura whereas Dolycoris baccarum Linn$\acute{e}$, Trialeurodes vaporariorum Westwood, Trichoplusia ni H$\ddot{u}$bner, and P. horticola were not recorded. On Brassicaceae were Brevicoyne brassicae Linn$\acute{e}$, M. persicae, Phaedon brassicae Baly, Phyllotreta striolata Fabricius, Plutella xylostella Linn$\acute{e}$, Hellula undalis Fabricius, S. litura, Pieris rapae Linn$\acute{e}$, Artogeia rapae Linn$\acute{e}$, and Athalia rosae ruficornis Jakovlev, but six species including Frankliniella intonsa Trybom were not recorded. The degree of damage by insect pests on Apiaceae was low, five species including Tetranychus kanzawai kishida, F. intonsa, T. vaporariorum, S. litura, and P. horticola were not recorded. The main insect pests on Liliaceae were Thyatira tabaci Lindeman, Acrolepiopsis sapporensis Matsumura, S. exigua, and Liriomyza chinensis Kato. The damage to Compositae by insect pests was relatively low except that of S. litura.

Occurrence of Insect Pests in Rubus coreanus Miquel (복분자딸기에서 발생하는 해충 종류 및 발생 양상)

  • Lim, Ju-Rak;Choi, Seon-U;Kim, Ju-Hee;Lee, Ki-Kwon;Cheong, Seong-Soo;Ryu, Jeong;Hwang, Chang-Yeon
    • Korean journal of applied entomology
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    • v.49 no.2
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    • pp.97-103
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    • 2010
  • In this study, 5 species (Tetranychus kanzawai Kishida, Endoclyta excrescens (Butler), leaf roller caterpillar (Adoxophyes orana Fisher), Anomis mesogona (Walker), and Aulacaspis rosae (Bouche)) were found in Rubus coreanus Miquel in Jeonbuk province, from 2006 to 2008. T. kanzawai appeared in mid-May and showed three peaks in late June, mid-July, and late August. Its density was over 10 adults per leaf. A. mesogona appeared in mid-June and showed two peaks in late July, and early October. Of the 28 insect pests in pre-harvesting, the 7 main species were T. kanzawai, T. urticae, A. orana, Lygocoris lucorum Meyer, Frankliniella intonsa (Trybom), Psylliodes punctifrons Baly and Motschulskyia serrata (Matsumura). Of the 19 insect pests in after-harvesting, the 6 main species were T. kanzawai, E. excrescens, A. mesogona, A. orana, P. punctifrons and A. rosae. Growth of R. coreanus decreased when insect pests were not managed and yields decreased approx. 7% a year. Management of insect pests in field using pesticide was not different.

Greenhouse Whitefly and Thrips Management Model Using Natural Enemies in Semi-forcing Culture of Tomato (토마토 반촉성 시설 재배에서 천적중심 온실가루이와 총채벌레 관리모델)

  • Jeong, Tae-Sung;Hwang, Mi-Ran;Hwang, Se-Jung;Lee, Jae-Hong;Lee, An-Soo;Won, Heon-Seop;Hong, Dae-Ki;Cho, Jum-Rae;Ham, Eun Hye
    • Korean journal of applied entomology
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    • v.56 no.4
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    • pp.403-412
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    • 2017
  • To investigate the control effect of insect pests by natural enemies, sticky traps were used in commercial tomato greenhouses in Chun-cheon and the experiment fields of Gangwon-do Agricultural Research and Extension Services, Republic of Korea using semi-forcing culture (February to June). We selected low toxicity pesticides, environment-friendly agricultural materials (EFAM), and natural enemies of the study species, combinations of which have been previously used in farms to control insect pests. In this study, Trialeurodes vaporariorum and thrips, which are major agricultural insect pests, were studied in experimental greenhouses. The adult T. vaporariorum population was observed in mid-April and the population of thrips showed occurrences in early April. Regarding seasonal fluctuation, T. vaporariorum peaked in mid-May and thrips peaked after June. one insecticide, spiromesifen suspension concentrate (SC); one fungicide, cyazofamid SC; and two EFAMs containing neem tree extract were shown to be slightly toxic to Encarsia formosa and Orius laevigatus. The results of this study could be used to develop management models using natural enemies of control the insect pests; T. vaporariorum and thrips in semi-forcing culture of tomato.