Korean Journal of Applied Entomology, Mar 30, 2009
Paromius exiguus (Distant) has caused serious damage by pecky grains around Gimpo paddy fields in... more Paromius exiguus (Distant) has caused serious damage by pecky grains around Gimpo paddy fields in 2001. We conducted field and laboratory studies to determine the seasonal occurrence and age distribution of P. exiguus on the three major host plants. The overwintering P. exiguus was found mainly on the basal part of gramineae weeds in various localities. After overwintering, in mid-May, the adults aggregated on the grain parts of Imperata cylindrica, laid their eggs and nymphs developed into adults on the same host plants. By the time, the Calamagrostis epigeios colony had newly occupied I. cylindrica areas, the nymphs and adults of first generation had already moved to the second host. The second generation of P. exiguus, after having completed its life cycle on C. epigeios, the newly emerged adults migrated to the rice plants and other gramineae weeds in early August. Afterwards, they complete its third generation cycle where they can move to the overwintering site again. P. exiguus has the five nymphal stages and each nymphal stage could be determined by head or prothoracic width. On the I. cylindrica and O. sativa hosts, the age distribution of P. exiguus showed a simple structure as each stage ratio increased stepwise with time. But in case of C. epigeios, as the newly emerged adults and immature nymphs continuously migrate after a month from the I. cylindrica, the age structure became remarkably complex. The peak nymphal density was observed when the ratio of third and forth instar was the highest in the population. The finding about the specific age structure on each generation of the insect would be very useful in control decision making on the major host plants. It is also important to consider the host's specificity to pesticide sensitivity in relation to various nymphal stages.
Bemisia tabaciMediterranean (Gennadius) (Hemiptera: Aleyrodidae) is an economically important ins... more Bemisia tabaciMediterranean (Gennadius) (Hemiptera: Aleyrodidae) is an economically important insect pest worldwide. Previously, we have reported that mostB.tabaciMediterranean (MED) populations occurring in greenhouse tomatoes in Korea have been displaced from well-differentiated two genetic clusters (C1 and C2) to one (C2) during one-year period. To elucidate factors responsible for this phenomenon, we compared life history parameters of these two different genetic clusters through single and cross mating experiments on two different host plants, cucumber and tobacco, at 26°C. Intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (Ro) were significantly higher in the dominating cluster (C2) (0.247, 1.280, and 192.402, respectively on cucumber; 0.226, 1.253, and 133.792, respectively on tobacco) than in the other cluster (C1) (0.149, 1.161, and 50.539, respectively on cucumber; 0.145, 1.156, and 53.332, respectively on tobacco). Overall performances...
Aphis gossypii Glover (Hemiptera: Aphididae) is a serious polyphagous agricultural pest worldwide... more Aphis gossypii Glover (Hemiptera: Aphididae) is a serious polyphagous agricultural pest worldwide. In the present study, we used eight microsatellite markers to investigate the genetic structure and diversity of A. gossypii populations in Korea. Samples were collected from 37 locations in Korea (18 populations in 2016, 14 populations in 2017, and five populations in 2018) from pepper plants. A. gossypii had low to moderate genetic diversity, and expected heterozygosity (HE) ranged from 0.354 to 0.719. A Mantel test of isolation by distance indicated no relationship between genetic structure and geographic distance among all populations (r2 = 0.0004, p = 0.370), suggesting high gene flow among populations in Korea. Populations of A. gossypii in Korea were divided into two distinct genetic clusters (ΔK = 2). In 2016 and 2017, the genetic clusters changed into opposite genetic structures within one year mostly in northwest and southeast parts of Korea. Possible relevance of study resul...
Both herbivores that consume transgenic crops and their predators can be exposed to insecticidal ... more Both herbivores that consume transgenic crops and their predators can be exposed to insecticidal proteins expressed in those crops. We conducted a tritrophic bioassay to evaluate the ecotoxicological impacts that Bt cabbage (Brassica oleracea var. capitata) expressing Cry1Ac1 protein might have on the wolf spider (Pardosa astrigera), a non-target generalist predator. Enzyme-Linked Immunosorbent Assays indicated that protein levels were 4.61 ng g-1 dry weight in fruit flies (Drosophila melanogaster) fed with the transgenic cabbage and 1.86 ng g-1 dry weight in the wolf spiders that preyed upon them. We also compared the life history traits of spiders collected from Bt versus non-Bt cabbage and found no significant differences in their growth, survival, and developmental rates. Because Bt cabbage did not affect the growth of fruit flies, we conclude that any indirect effects that this crop had on the wolf spider were probably not mediated by prey quality. Therefore, exposure to Cry1Ac...
Ground beetles were collected by pitfall trapping to compare their species richness between conif... more Ground beetles were collected by pitfall trapping to compare their species richness between conifer plantations (14 sites) and regenerating forests (14 sites) and among forest ages and to examine how different functional groups responded to forest type, forest age, patch size, elevation, and geographic location in terms of abundance and richness. Ground beetles were collected from middle August to late October, 2008. A total of 34 species were identified from 3,156 collected ground beetles. Individual-based rarefaction curves showed greater species richness in regenerating forests, especially in 40-50-year-old forests, than in conifer plantations. Stepwise multiple regression analysis showed that patch size and elevation were major predictors of species richness and/or abundance of forest specialists, brachypterous species, and large-and medium-bodied species. A multivariate regression tree indicated that patch size and elevation were major predictors of assemblage structure. Although our results suggest that maintaining forest areas adjacent to agricultural landscapes may be essential to preserve ground beetle assemblages irrespective of forest types, further study is necessary to clarify the effects of habitat quality and amount on ground beetles in forests.
The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), is a major ... more The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), is a major pest of rice and has long-range migratory behavior in Asia. Microsatellite markers (simple sequence repeats) have been widely used to determine the origins and genetic diversity of insect pests. We identified novel microsatellite loci for S. furcifera samples collected from Laos, Vietnam, and three localities in Bangladesh from next-generation Roche 454 pyrosequencing data. Size polymorphism at 12 microsatellite loci was verified for 40 adult individuals collected from Shinan, South Korea. The average number of alleles per locus was 7.92. The mean values of observed (Ho) and expected heterozygosities (HE) were 0.615 and 0.757, respectively. These new microsatellite markers will be a resource for future ecological genetic studies of S. furcifera samples across more broad geographic regions in Asia and may assist in estimations of genetic differentiation and gene flow among populations for...
To assess the potential adverse effects of a Bt rice line (Japonica rice cultivar, Nakdong) expre... more To assess the potential adverse effects of a Bt rice line (Japonica rice cultivar, Nakdong) expressing a synthetic cry1Ac1 gene, C7-1-9-1-B, which was highly active against all larval stages of Cnaphalocrocis medinalis (Guené e) (Lepidoptera: Crambidae), we investigated the community structure of spiders in Bt and non-Bt rice Þelds during the rice-growing season in 2007 and 2008 in Chungcheongnam-do, Korea. Spiders were surveyed with a sweep net and suction device. Suction sampling captured more spiders, measured in terms of species level and abundance, than sweeping. Araneidae and Thomisidae were captured more by sweeping, and certain species were captured only by sweeping. These Þndings show that both suction and sweep sampling methods should be used because these methods are most likely complementary. In total, 29 species in 23 genera and nine families were identiÞed from the 4,937 spiders collected, and both Bt and non-Bt rice Þelds showed a typical Korean spider assemblage. The temporal patterns of spider species richness and spider abundance were very similar between Bt and non-Bt rice, although signiÞcant differences in species richness were observed on a few occasions. Overall, spider community structure, including diversity, the dominant species, and abundance did not differ between Bt and non-Bt rice. The results of the study indicated that the transgenic Cry1Ac rice lines tested in this study had no adverse effects on the spider community structure of the rice Þelds.
First known female of the sac spider Clubiona zacharovi Mikhailov, 1991 is described from Korea. ... more First known female of the sac spider Clubiona zacharovi Mikhailov, 1991 is described from Korea. This is a rare species inhabiting in the plant litter or under the stone in mountain sites.
Thrips palmi Karny, melon thrips was introduced and first recorded in 1993 in Korea. This species... more Thrips palmi Karny, melon thrips was introduced and first recorded in 1993 in Korea. This species has become a serious pest of vegetable and ornamental crops. The CLIMEX simulation was applied to T. palmi to predict its potential geographic distribution in Korea under the Representative Concentration Pathway (RCP) 8.5 climate change scenario. In the CLIMEX simulation, the ecoclimatic index was calculated, and compared in each simulated year and each simulated location. The map comparisons show good agreements between simulated and present distributions of T. palmi, indicating that the CLIMEX model has promising potential for prediction of future distributions of this species in Korea. In the near future, until the year 2020, all the western and eastern parts of Korea show favorable to marginal suitability for T. palmi populations in the fields. After the year 2040, potential distributions shift from no persistence to favorable for establishment and persistence from coastal to interi...
Developmental time decreased with increasing temperature up to 32.5°C in all stages. The total de... more Developmental time decreased with increasing temperature up to 32.5°C in all stages. The total developmental time was longest at 12.5°C (64.2 days) and shortest at 32.5°C (9.2 days). The lower developmental threshold was 10.6, 10.6, 9.1, and 10.7°C for egg, larva, prepupa, and pupa, respectively. The thermal constant required to complete the respective stage was 71.7, 59.2, 18.1, and 36.8DD. The lower threshold temperature and thermal constant were 10.6°C and 183.3DD, respectively, for total immature development. The nonlinear relationship between developmental rate and temperature was well described by the modified Sharpe and DeMichele biophysical model (r 2 = 0.905-0.998). The distribution of developmental completion of each stage was described by the 3parameter Weibull function (r 2 = 0.855-0.927). The temperature-dependent developmental models of T. palmi developed in this study could be used to predict its seasonal phenology in field and greenhouse vegetable crops.
Two cherry tomato plant cultivars (Lycopersicon esculentum Miller, cultivars 'Koko' and 'Pepe') w... more Two cherry tomato plant cultivars (Lycopersicon esculentum Miller, cultivars 'Koko' and 'Pepe') were supplied with high (395 ppm), medium (266 ppm) and low (199 ppm) concentrations of nitrogen to determine the influence of nitrogen fertilization on development, cultivar preference and honeydew production by greenhouse whiteflies, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae). The nitrogen, protein, and chlorophyll contents of tomato leaves were higher in the high nitrogen supplied plants than in the medium or low nitrogen supplied plants, but the sugar content showed an inverse relationship. The developmental times of eggs and nymphs decreased as the nitrogen concentrations increased in both cultivars. The preference of T. vaporariorum was compared by counting the number of eggs deposited on leaves in choice and non-choice tests. In the non-choice test, no significant nitrogen treatment effects were observed but the upper plant stratum was preferred for egg laying. In the choice test, there were significant main effects of cultivar and nitrogen concentration. T. vaporariorum laid eggs more on leaves of plants with higher nitrogen at the upper stratum. In both experiments, T. vaporariorum preferred the 'Koko' cultivar to the 'Pepe' cultivar. The honeydew production of T. vaporariorum nymphs increased with decreasing nitrogen treatment concentrations. The largest honeydew production was detected in the 'Pepe' cultivar grown at low nitrogen concentration. It is concluded that cultivar 'Pepe' had an advantage over 'Koko' in term of T. vaporariorum management program in tomato greenhouses.
Two new species of the genus Atypus, Atypus sternosulcus new species from Andong and A. suwonensi... more Two new species of the genus Atypus, Atypus sternosulcus new species from Andong and A. suwonensis new species from Suwon, are newly described from Korea.
Your article is protected by copyright and all rights are held exclusively by Springer Science+Bu... more Your article is protected by copyright and all rights are held exclusively by Springer Science+Business Media B.V.. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication. Sublethal effects of fenpyroximate and pyridaben on two predatory mite species, Neoseiulus womersleyi and Phytoseiulus persimilis (Acari, Phytoseiidae)
Effects of timing of overwintering larval-cocoon formation, constant temperature, and soil moistu... more Effects of timing of overwintering larval-cocoon formation, constant temperature, and soil moisture on postdiapause development of Carposina sasakii Matsumura were examined. Also, a forecasting model of its spring emergence was constructed based on degree-days. The development time from overwintering larva to adult emergence was not signiÞcantly different among soil moistures in the range of 10 Ð20%, but it was different according to the timing of larval-cocoon formation in the previous year. The weight of cocoons containing an overwintering larva was less for cocoons formed after 6 October than cocoons formed before 15 September. There was a positive correlation (r ϭ 0.47) between the overwintering larval-cocoon weight and its development time to adult. Approximately 3Ð 4% of C. sasakii showed a prolonged diapause spending 2 yr as larval-cocoons in the soil. A greater proportion (18.4%) of heavier cocoons (Ͼ0.040 g) remained in diapause in the current year compared with normal weighed cocoons (0.022Ð 0.040 g) (1.6%) or lighter cocoons (Ͻ0.022 g) (0%). The adult spring emergence showed a two-peak emergence pattern in which the Þrst major peak occurred in late June and the second smaller peak in late July. A bimodal distribution model was developed to describe this emergence pattern. The bimodal model predicted more accurately C. sasakii spring emergence times than the Weibull model.
Outlier detection and cleaning procedures were evaluated to estimate mathematical restricted vari... more Outlier detection and cleaning procedures were evaluated to estimate mathematical restricted variogram models with discrete insect population count data. Because variogram modeling is significantly affected by outliers, methods to detect and clean outliers from data sets are critical for proper variogram modeling. In this study, we examined spatial data in the form of discrete measurements of insect counts on a rectangular grid. Two well-known insect pest population data were analyzed; one data set was the western flower thrips, Frankliniella occidentalis (Pergande) on greenhouse cucumbers and the other was the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) on greenhouse cherry tomatoes. A spatial additive outlier model was constructed to detect outliers in both the isolated and patchy spatial distributions of outliers, and the outliers were cleaned with the neighboring median cleaner. To analyze the effect of outliers, we compared the relative nugget effects of data cleaned of outliers and data still containing outliers after transformation. In addition, the correlation coefficients between the actual and predicted values were compared using the leave-one-out crossvalidation method with data cleaned of outliers and non-cleaned data after unbiased back transformation. The outlier detection and cleaning procedure improved geostatistical analysis, particularly by reducing the nugget effect, which greatly impacts the prediction variance of kriging. Consequently, the outlier detection and cleaning procedures used here improved the results of geostatistical analysis with highly skewed and extremely fluctuating data, such as insect counts.
; however, these previous studies did not incorporate a population dynamics model for R. clavatus... more ; however, these previous studies did not incorporate a population dynamics model for R. clavatus, even though this could enhance the effectiveness of control methods and strategies. To develop a population dynamics model for R. clavatus, models of temperature-dependent development and fecundity of R. clavatus are essential.
Page 1. Quantitative Survivorship Analysis of the Velvetbean Caterpillar (Lepidoptera: Noctuidae)... more Page 1. Quantitative Survivorship Analysis of the Velvetbean Caterpillar (Lepidoptera: Noctuidae) Pupae in Soybean Fields in Louisiana JOON-HO LEE,l SETH J. JOHNSON," ANDVERNON L. WRIGHT" Department of Entomology ...
Page 1. Microhabitat Distribution of Velvetbean Caterpillar (Lepidoptera: Noctuidae) Pupae in Soy... more Page 1. Microhabitat Distribution of Velvetbean Caterpillar (Lepidoptera: Noctuidae) Pupae in Soybean Fields in Louisiana JOON-HO LEE' ANDSETH J. JOHNSON" Department of Entomology, Louisiana Agricultural Experiment ...
Korean Journal of Applied Entomology, Mar 30, 2009
Paromius exiguus (Distant) has caused serious damage by pecky grains around Gimpo paddy fields in... more Paromius exiguus (Distant) has caused serious damage by pecky grains around Gimpo paddy fields in 2001. We conducted field and laboratory studies to determine the seasonal occurrence and age distribution of P. exiguus on the three major host plants. The overwintering P. exiguus was found mainly on the basal part of gramineae weeds in various localities. After overwintering, in mid-May, the adults aggregated on the grain parts of Imperata cylindrica, laid their eggs and nymphs developed into adults on the same host plants. By the time, the Calamagrostis epigeios colony had newly occupied I. cylindrica areas, the nymphs and adults of first generation had already moved to the second host. The second generation of P. exiguus, after having completed its life cycle on C. epigeios, the newly emerged adults migrated to the rice plants and other gramineae weeds in early August. Afterwards, they complete its third generation cycle where they can move to the overwintering site again. P. exiguus has the five nymphal stages and each nymphal stage could be determined by head or prothoracic width. On the I. cylindrica and O. sativa hosts, the age distribution of P. exiguus showed a simple structure as each stage ratio increased stepwise with time. But in case of C. epigeios, as the newly emerged adults and immature nymphs continuously migrate after a month from the I. cylindrica, the age structure became remarkably complex. The peak nymphal density was observed when the ratio of third and forth instar was the highest in the population. The finding about the specific age structure on each generation of the insect would be very useful in control decision making on the major host plants. It is also important to consider the host's specificity to pesticide sensitivity in relation to various nymphal stages.
Bemisia tabaciMediterranean (Gennadius) (Hemiptera: Aleyrodidae) is an economically important ins... more Bemisia tabaciMediterranean (Gennadius) (Hemiptera: Aleyrodidae) is an economically important insect pest worldwide. Previously, we have reported that mostB.tabaciMediterranean (MED) populations occurring in greenhouse tomatoes in Korea have been displaced from well-differentiated two genetic clusters (C1 and C2) to one (C2) during one-year period. To elucidate factors responsible for this phenomenon, we compared life history parameters of these two different genetic clusters through single and cross mating experiments on two different host plants, cucumber and tobacco, at 26°C. Intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (Ro) were significantly higher in the dominating cluster (C2) (0.247, 1.280, and 192.402, respectively on cucumber; 0.226, 1.253, and 133.792, respectively on tobacco) than in the other cluster (C1) (0.149, 1.161, and 50.539, respectively on cucumber; 0.145, 1.156, and 53.332, respectively on tobacco). Overall performances...
Aphis gossypii Glover (Hemiptera: Aphididae) is a serious polyphagous agricultural pest worldwide... more Aphis gossypii Glover (Hemiptera: Aphididae) is a serious polyphagous agricultural pest worldwide. In the present study, we used eight microsatellite markers to investigate the genetic structure and diversity of A. gossypii populations in Korea. Samples were collected from 37 locations in Korea (18 populations in 2016, 14 populations in 2017, and five populations in 2018) from pepper plants. A. gossypii had low to moderate genetic diversity, and expected heterozygosity (HE) ranged from 0.354 to 0.719. A Mantel test of isolation by distance indicated no relationship between genetic structure and geographic distance among all populations (r2 = 0.0004, p = 0.370), suggesting high gene flow among populations in Korea. Populations of A. gossypii in Korea were divided into two distinct genetic clusters (ΔK = 2). In 2016 and 2017, the genetic clusters changed into opposite genetic structures within one year mostly in northwest and southeast parts of Korea. Possible relevance of study resul...
Both herbivores that consume transgenic crops and their predators can be exposed to insecticidal ... more Both herbivores that consume transgenic crops and their predators can be exposed to insecticidal proteins expressed in those crops. We conducted a tritrophic bioassay to evaluate the ecotoxicological impacts that Bt cabbage (Brassica oleracea var. capitata) expressing Cry1Ac1 protein might have on the wolf spider (Pardosa astrigera), a non-target generalist predator. Enzyme-Linked Immunosorbent Assays indicated that protein levels were 4.61 ng g-1 dry weight in fruit flies (Drosophila melanogaster) fed with the transgenic cabbage and 1.86 ng g-1 dry weight in the wolf spiders that preyed upon them. We also compared the life history traits of spiders collected from Bt versus non-Bt cabbage and found no significant differences in their growth, survival, and developmental rates. Because Bt cabbage did not affect the growth of fruit flies, we conclude that any indirect effects that this crop had on the wolf spider were probably not mediated by prey quality. Therefore, exposure to Cry1Ac...
Ground beetles were collected by pitfall trapping to compare their species richness between conif... more Ground beetles were collected by pitfall trapping to compare their species richness between conifer plantations (14 sites) and regenerating forests (14 sites) and among forest ages and to examine how different functional groups responded to forest type, forest age, patch size, elevation, and geographic location in terms of abundance and richness. Ground beetles were collected from middle August to late October, 2008. A total of 34 species were identified from 3,156 collected ground beetles. Individual-based rarefaction curves showed greater species richness in regenerating forests, especially in 40-50-year-old forests, than in conifer plantations. Stepwise multiple regression analysis showed that patch size and elevation were major predictors of species richness and/or abundance of forest specialists, brachypterous species, and large-and medium-bodied species. A multivariate regression tree indicated that patch size and elevation were major predictors of assemblage structure. Although our results suggest that maintaining forest areas adjacent to agricultural landscapes may be essential to preserve ground beetle assemblages irrespective of forest types, further study is necessary to clarify the effects of habitat quality and amount on ground beetles in forests.
The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), is a major ... more The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), is a major pest of rice and has long-range migratory behavior in Asia. Microsatellite markers (simple sequence repeats) have been widely used to determine the origins and genetic diversity of insect pests. We identified novel microsatellite loci for S. furcifera samples collected from Laos, Vietnam, and three localities in Bangladesh from next-generation Roche 454 pyrosequencing data. Size polymorphism at 12 microsatellite loci was verified for 40 adult individuals collected from Shinan, South Korea. The average number of alleles per locus was 7.92. The mean values of observed (Ho) and expected heterozygosities (HE) were 0.615 and 0.757, respectively. These new microsatellite markers will be a resource for future ecological genetic studies of S. furcifera samples across more broad geographic regions in Asia and may assist in estimations of genetic differentiation and gene flow among populations for...
To assess the potential adverse effects of a Bt rice line (Japonica rice cultivar, Nakdong) expre... more To assess the potential adverse effects of a Bt rice line (Japonica rice cultivar, Nakdong) expressing a synthetic cry1Ac1 gene, C7-1-9-1-B, which was highly active against all larval stages of Cnaphalocrocis medinalis (Guené e) (Lepidoptera: Crambidae), we investigated the community structure of spiders in Bt and non-Bt rice Þelds during the rice-growing season in 2007 and 2008 in Chungcheongnam-do, Korea. Spiders were surveyed with a sweep net and suction device. Suction sampling captured more spiders, measured in terms of species level and abundance, than sweeping. Araneidae and Thomisidae were captured more by sweeping, and certain species were captured only by sweeping. These Þndings show that both suction and sweep sampling methods should be used because these methods are most likely complementary. In total, 29 species in 23 genera and nine families were identiÞed from the 4,937 spiders collected, and both Bt and non-Bt rice Þelds showed a typical Korean spider assemblage. The temporal patterns of spider species richness and spider abundance were very similar between Bt and non-Bt rice, although signiÞcant differences in species richness were observed on a few occasions. Overall, spider community structure, including diversity, the dominant species, and abundance did not differ between Bt and non-Bt rice. The results of the study indicated that the transgenic Cry1Ac rice lines tested in this study had no adverse effects on the spider community structure of the rice Þelds.
First known female of the sac spider Clubiona zacharovi Mikhailov, 1991 is described from Korea. ... more First known female of the sac spider Clubiona zacharovi Mikhailov, 1991 is described from Korea. This is a rare species inhabiting in the plant litter or under the stone in mountain sites.
Thrips palmi Karny, melon thrips was introduced and first recorded in 1993 in Korea. This species... more Thrips palmi Karny, melon thrips was introduced and first recorded in 1993 in Korea. This species has become a serious pest of vegetable and ornamental crops. The CLIMEX simulation was applied to T. palmi to predict its potential geographic distribution in Korea under the Representative Concentration Pathway (RCP) 8.5 climate change scenario. In the CLIMEX simulation, the ecoclimatic index was calculated, and compared in each simulated year and each simulated location. The map comparisons show good agreements between simulated and present distributions of T. palmi, indicating that the CLIMEX model has promising potential for prediction of future distributions of this species in Korea. In the near future, until the year 2020, all the western and eastern parts of Korea show favorable to marginal suitability for T. palmi populations in the fields. After the year 2040, potential distributions shift from no persistence to favorable for establishment and persistence from coastal to interi...
Developmental time decreased with increasing temperature up to 32.5°C in all stages. The total de... more Developmental time decreased with increasing temperature up to 32.5°C in all stages. The total developmental time was longest at 12.5°C (64.2 days) and shortest at 32.5°C (9.2 days). The lower developmental threshold was 10.6, 10.6, 9.1, and 10.7°C for egg, larva, prepupa, and pupa, respectively. The thermal constant required to complete the respective stage was 71.7, 59.2, 18.1, and 36.8DD. The lower threshold temperature and thermal constant were 10.6°C and 183.3DD, respectively, for total immature development. The nonlinear relationship between developmental rate and temperature was well described by the modified Sharpe and DeMichele biophysical model (r 2 = 0.905-0.998). The distribution of developmental completion of each stage was described by the 3parameter Weibull function (r 2 = 0.855-0.927). The temperature-dependent developmental models of T. palmi developed in this study could be used to predict its seasonal phenology in field and greenhouse vegetable crops.
Two cherry tomato plant cultivars (Lycopersicon esculentum Miller, cultivars 'Koko' and 'Pepe') w... more Two cherry tomato plant cultivars (Lycopersicon esculentum Miller, cultivars 'Koko' and 'Pepe') were supplied with high (395 ppm), medium (266 ppm) and low (199 ppm) concentrations of nitrogen to determine the influence of nitrogen fertilization on development, cultivar preference and honeydew production by greenhouse whiteflies, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae). The nitrogen, protein, and chlorophyll contents of tomato leaves were higher in the high nitrogen supplied plants than in the medium or low nitrogen supplied plants, but the sugar content showed an inverse relationship. The developmental times of eggs and nymphs decreased as the nitrogen concentrations increased in both cultivars. The preference of T. vaporariorum was compared by counting the number of eggs deposited on leaves in choice and non-choice tests. In the non-choice test, no significant nitrogen treatment effects were observed but the upper plant stratum was preferred for egg laying. In the choice test, there were significant main effects of cultivar and nitrogen concentration. T. vaporariorum laid eggs more on leaves of plants with higher nitrogen at the upper stratum. In both experiments, T. vaporariorum preferred the 'Koko' cultivar to the 'Pepe' cultivar. The honeydew production of T. vaporariorum nymphs increased with decreasing nitrogen treatment concentrations. The largest honeydew production was detected in the 'Pepe' cultivar grown at low nitrogen concentration. It is concluded that cultivar 'Pepe' had an advantage over 'Koko' in term of T. vaporariorum management program in tomato greenhouses.
Two new species of the genus Atypus, Atypus sternosulcus new species from Andong and A. suwonensi... more Two new species of the genus Atypus, Atypus sternosulcus new species from Andong and A. suwonensis new species from Suwon, are newly described from Korea.
Your article is protected by copyright and all rights are held exclusively by Springer Science+Bu... more Your article is protected by copyright and all rights are held exclusively by Springer Science+Business Media B.V.. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication. Sublethal effects of fenpyroximate and pyridaben on two predatory mite species, Neoseiulus womersleyi and Phytoseiulus persimilis (Acari, Phytoseiidae)
Effects of timing of overwintering larval-cocoon formation, constant temperature, and soil moistu... more Effects of timing of overwintering larval-cocoon formation, constant temperature, and soil moisture on postdiapause development of Carposina sasakii Matsumura were examined. Also, a forecasting model of its spring emergence was constructed based on degree-days. The development time from overwintering larva to adult emergence was not signiÞcantly different among soil moistures in the range of 10 Ð20%, but it was different according to the timing of larval-cocoon formation in the previous year. The weight of cocoons containing an overwintering larva was less for cocoons formed after 6 October than cocoons formed before 15 September. There was a positive correlation (r ϭ 0.47) between the overwintering larval-cocoon weight and its development time to adult. Approximately 3Ð 4% of C. sasakii showed a prolonged diapause spending 2 yr as larval-cocoons in the soil. A greater proportion (18.4%) of heavier cocoons (Ͼ0.040 g) remained in diapause in the current year compared with normal weighed cocoons (0.022Ð 0.040 g) (1.6%) or lighter cocoons (Ͻ0.022 g) (0%). The adult spring emergence showed a two-peak emergence pattern in which the Þrst major peak occurred in late June and the second smaller peak in late July. A bimodal distribution model was developed to describe this emergence pattern. The bimodal model predicted more accurately C. sasakii spring emergence times than the Weibull model.
Outlier detection and cleaning procedures were evaluated to estimate mathematical restricted vari... more Outlier detection and cleaning procedures were evaluated to estimate mathematical restricted variogram models with discrete insect population count data. Because variogram modeling is significantly affected by outliers, methods to detect and clean outliers from data sets are critical for proper variogram modeling. In this study, we examined spatial data in the form of discrete measurements of insect counts on a rectangular grid. Two well-known insect pest population data were analyzed; one data set was the western flower thrips, Frankliniella occidentalis (Pergande) on greenhouse cucumbers and the other was the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) on greenhouse cherry tomatoes. A spatial additive outlier model was constructed to detect outliers in both the isolated and patchy spatial distributions of outliers, and the outliers were cleaned with the neighboring median cleaner. To analyze the effect of outliers, we compared the relative nugget effects of data cleaned of outliers and data still containing outliers after transformation. In addition, the correlation coefficients between the actual and predicted values were compared using the leave-one-out crossvalidation method with data cleaned of outliers and non-cleaned data after unbiased back transformation. The outlier detection and cleaning procedure improved geostatistical analysis, particularly by reducing the nugget effect, which greatly impacts the prediction variance of kriging. Consequently, the outlier detection and cleaning procedures used here improved the results of geostatistical analysis with highly skewed and extremely fluctuating data, such as insect counts.
; however, these previous studies did not incorporate a population dynamics model for R. clavatus... more ; however, these previous studies did not incorporate a population dynamics model for R. clavatus, even though this could enhance the effectiveness of control methods and strategies. To develop a population dynamics model for R. clavatus, models of temperature-dependent development and fecundity of R. clavatus are essential.
Page 1. Quantitative Survivorship Analysis of the Velvetbean Caterpillar (Lepidoptera: Noctuidae)... more Page 1. Quantitative Survivorship Analysis of the Velvetbean Caterpillar (Lepidoptera: Noctuidae) Pupae in Soybean Fields in Louisiana JOON-HO LEE,l SETH J. JOHNSON," ANDVERNON L. WRIGHT" Department of Entomology ...
Page 1. Microhabitat Distribution of Velvetbean Caterpillar (Lepidoptera: Noctuidae) Pupae in Soy... more Page 1. Microhabitat Distribution of Velvetbean Caterpillar (Lepidoptera: Noctuidae) Pupae in Soybean Fields in Louisiana JOON-HO LEE' ANDSETH J. JOHNSON" Department of Entomology, Louisiana Agricultural Experiment ...
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