• Korean journal of applied entomology
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• v.62 no.3
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• pp.161-169
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• 2023

Thrips are usually not exposed to insecticide spray due to hiding at holes, gaps, or crevices of host plants with their relatively small body sizes. This study devised a strategy to use a contact pheromone to suppress the seclusive behavior of the thrips, A contact pheromone identified as 7-methyltricosane (7TM) in the western flower thrips, Frankliniella occidentalis, was added to the diet to test the preference of the thrips. Although 7TM did not change the larval behavior, it significantly induced the avoiding behavior in male adults. In contrast, the contact pheromone was preferred by the female adults. Similar behavioral changes were also observed in another flower thrips, Frankliniella intonsa. Based on the behavioral changes induced by the contact pheromone, a mixture of 7TM and insecticide was applied to thrips infesting hot peppers in field conditions. Compared to spinetoram treatment, its mixture treatment with 7TM enhanced the control efficacy against thrips. Interestingly, 7TM treatment alone also gave slight reduction in F. intonsa density, suggesting a behavioral disruption of thrips by the contact pheromone. This study suggests a novel technology to control insect pests using contact pheromone by suppressing the seclusive behavior to avoid exposure to insecticide spray.

• Korean journal of applied entomology
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• v.45 no.1 s.142
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• pp.9-13
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• 2006

Seasonal occurrence of thrips and its damage on fruits were studied at in open field red pepper in Jeonbuk Province. The kind of thrips were Franklinella occidentalis and F. intonsa. The ratio of F. occidentalis was about 30% in periods of survey. Density of thrips increased in late May and showed peak occurrence in early to middle July. The peak occurrence of thrips was appeared at 4 pentad June, 2 pentad July, 3 pentad August, and 4 pentad September. The part of fruit damaged by thrips became discolored and roughed. When turned red, the colors of damaged parts changed from dark brown to yellowish brown. As a result, damage fruits by thrips decreased marketability. The percent of damaged fruits was highest in Imsil at 20.8% in early August. Density of thrips on flowers was highest in middle July.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.387-401
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• 2021

Thrips infesting hot peppers were monitored in greenhouses using yellow sticky traps. In addition, the hot peppers infected with tomato spotted wilt virus (TSWV) were observed during the monitoring period. The flower thrips (Frankliniella intonsa) were initially trapped at a low density just after transplanting seedlings of hot peppers at late March. The western flower thrips (Frankliniella occidentalis) were trapped after mid April. These two thrips represented more than 98% of the total thrips attracted to the traps after May, in which F. intonsa showed higher occurrence frequency than F. occidentalis. The total number of thrips had two peaks at mid May with a small and short-term peak and at June-July with a large and long-term peak. The trapped thrips exhibited inconsistent sex ratios, suggesting a seasonal parthenogenesis. Different geographical populations were varied in cytochrome oxidase I sequences, in which local populations in Andong shared a high sequence similarity. TSWV-infected hot peppers, which might be mediated by these two thrips species, were observed and confirmed by an immunoassay kit and a molecular diagnosis using RT-PCR. In addition, the TSWV was detected in F. occidentalis collected from the infected hot peppers. Three open reading frames (NS_S, N, and NS_M) of the isolated TSWV genomes were sequenced and showed multiple point mutations containing missense mutations among geographical variants. When the isolated TSWV was fed to nonvirulent thrips of F. occidentalis, the virus was detected in both larvae and adults. However, the viral replication occurred in larvae, but not in adults.

• Research in Plant Disease
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• v.26 no.4
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• pp.264-271
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• 2020

We have developed a simultaneous diagnostic method that can identify both the species of thrips and tomato spotted wilt virus (TSWV) that are problematic in chrysanthemum plants. This is a method of amplifying DNA by performing reverse transcription-polymerase chain reaction by simultaneously adding primers specific to TSWV coat protein (N) gene and primers specific to the internal transcribed spacer 2 region of Frankliniella occidentalis and F. intonsa using total nucleic acid extracted from one thrips. The sizes of DNA fragments for TSWV, F. occidentalis, and F. intonsa were 777, 287, and 367 bp, respectively. These results showed species identification of thrips and whether thrips carrying TSWV can be simultaneously confirmed. Further usefulness of the simultaneous diagnostic method was made from greenhouse survey at chrysanthemum greenhouses in Taean (Chungcheongnam-do) and Changwon (Gyeongsangnam-do) to investigate the identification of thrips species and the rate of thrips carrying TSWV. Of thrips collected from the greenhouses, 83.7% thrips was F. occidentalis and 72.9% F. occidentalis carried TSWV in Taean. Similarly, the diagnostic method showed that 92.2% thrips was F. occidentalis and 84.0% F. occidentalis carried TSWV in Changwon. These results confirm that F. occidentalis is a dominant thrips species and the thrips species plays a crucial role in the transmission of TSWV in chrysanthemum plants in the greenhouses. Taken together, this study showed a simple diagnostic method for thrips identification and epidemiological studies of the timing and spread of TSWV through thrips in chrysanthemum greenhouses in South Korea.

• Korean journal of applied entomology
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• v.53 no.1
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• pp.27-34
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• 2014

Entomopathogenic fungi were isolated from Bemisia tabaci in an Oriental melon field, and their growth characteristics, factors related to a natural outbreak, and infectivity against Bemisia tabaci, Tetranychus urticae, and Frankliniella intonsa were investigated. The isolates had erect conidiophores bearing whorls of 4-6 phialides with a swollen base where cylindrical conidia of $3.0-3.4{\mu}m$ were attached. The isolates were identified as Isaria fumosorosea on the basis of morphological characteristics and an ITS sequence with 99% similarity. I. fumosorosea IFs-08 grew well on Sabouraud dextrose agar+yeast extract medium(3.2 mm/day/$24^{\circ}C$); it grew better at $35^{\circ}C$ than at $15^{\circ}C$. The isolates of I. fumosorosea-IFs were highly infective and killed 93.9-96.7% B. tabaci, 84.9-92.0% T. urticae, and 81.5-84.4% F. intonsa in bioassay, whereas three isolates (Isaria tenuipes, Isaria farinosa, and Isaria fumosorosea) from KACC showed a low infectivity of 10-20%. To the best of our knowledge, this is the first report of I. fumosorosea isolated from B. tabaci in Korea.

• 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.

• Korean Journal of Medicinal Crop Science
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• v.27 no.1
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• pp.17-23
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• 2019

Background: Cnidium officinale Makino and Ligusticum chuanxiong Hort. are important medicinal crops in Korea. However, there is insufficient information on the identification of thrips, which attack these plants. Until now, one species of thrips has been recorded as a main pest. Methods and Results: To identify the thrips emerging in C. officinale Makino and L. chuanxiong Hort., these plants were independently cultivated in two local areas. Thirty individuals of each plant species were selected randomly and surveyed for the presence of thrips. After confirming the existence of thrips, 100 thrips individuals were collected from each crop using the beating method. To identify thrips species, we performed PCR-restriction fragment length polymorphism (RFLP)-based analysis using ITS2 primer sets. Six thrips species were identified: western flower thrips (Frankliniella occidentalis), flower thrips (F. intonsa), onion thrips (Thrips tabaci), chrysanthemum thrips (T. nigropilosus), chilli thrips (Scirtothrips dorsalis), and grass thrips (Anaphothrips obscurus). The proportion of these species differed between the host plant species. Conclusions: Six thrips species were major pests of two medicinal crops. Integrated pest management is required to control these thrips species, and will enhance the yield and quality of C. officinale and L. chuanxiong.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.517-524
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• 2018

The purpose of this study was to investigate the density of thrips, and insecticidal resistance for effective control of Western flower thrips in greenhouse. The presence and density of the thrips was investigated using yellow colored-sticky trap in a cucumber field from May to August in Cheon-an. The results of the investigation revealed the existence of the following thrips species; Frankliniella occidentalis, F. intonsa, Thrips palmi, T. tabaci, Scirtothrips dorsalis, Microcephalothrips abdominalis, and T. nigropilosus. The predominant pest was found to be the western flower thrips. To survey the western flower thrips insecticidal resistance, we established the discriminating concentration (DC), recommended concentration (RC) and $2{\times}$recommended concentration ($2{\times}RC$) of nine insecticides; Emamectin benzoate EC, spinetoram SC, Chlorfenapyr EC, Spinosad SC, Cyantraniliprole EC, Acetamiprid WP, Dinotefuran WG, thiacloprid SC and thiamethoxam SC. The bioassay of about five local populations was conducted using the leaf-dipping method. In all local populations, insecticidal resistance in western flower thrips had not developed in emamectin benzoate EC (RC, $10.8{\mu}L\;L^{-1}$), chlorfenapyr EC (RC, $50.0{\mu}L\;L^{-1}$), spinetoram SC (RC, $25.0mg\;L^{-1}$), and spinosad SC (RC, $50.0mg\;L^{-1}$). However, insecticidal resistance in RC was found to have developed in cyantraniliprole EC (RC, $50.0{\mu}L\;L^{-1}$) and four insecticides of neonicotinoid type. Insecticidal activity of 95% or more was observed in each population when cyantraniliprole EC tested in $2{\times}RC$. However, the neonicotinoid types showed different insecticidal activity in $2{\times}RC$.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.601-615
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• 2013

This study was conducted to compare the community structure and biodiversity of arthropods between conventional and organic red pepper fields. A total of 36 species of 24 families belonging to 10 orders from collected 28,718 arthropods; 6,901 individuals from conventional field and 21,871 individuals from organic field. A number of species comprising arthropod community was same in both fields as 32 species. Species richness of Diptera was the highest in conventional field and that of Hymenoptera and Colembolla was the highest in organic field. Abundance of Frankliniella intonsa was the highest regardless of farming method. Helicoverpa assulta was dominant in conventional field, and Homidia mediaseta, Diptera sp. 4 and Pardosa astrigera were dominant in organic field. Diversity of community on the ground was higher in organic field and statistically different. Similarity of arthropod community showed difference with 34.07% on the ground and 26.95% in the plant above ground. In the ecologically functional guild: species richness of general, pest and parasitoid of natural enemy groups in the plant above ground were statistically different and pest and parasitoid groups were higher in organic field, abundance of predator group of natural enemy on the ground was 2 times higher in organic field and statistically different and diversity of general and parasitoid groups in the plant above ground were statistically different. In the relative occupancy rate, pest group was the highest in conventional field and decomposer group was the highest in organic field. The results of present study is considered to provide useful information of arthropod community for developing efficient insect pest management in organic farming.