Chang-Yeon Hwang

Biological Control of Cotton Aphid by Aphidius colemani(Hymenoptera: Braconidae) in Watermelon Greenhouses

Biological control of Aphis gossypii by natural enemies was carried out in watermelon from April to June. Aphidius colemani was released 3 times at rate of to control A. gossypii(April 24, May 8, and May 22 in 2007). In A. colemani-released plots, A. gossypii showed low population density of

An Investigation and Evaluation of Insect Pests in Greenhouse Vegetables in Jeonbuk Province

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 Hbner 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, Trialeurodes vaporariorum Westwood, Trichoplusia ni Hbner, and P. horticola were not recorded. On Brassicaceae were Brevicoyne brassicae Linn, M. persicae, Phaedon brassicae Baly, Phyllotreta striolata Fabricius, Plutella xylostella Linn, Hellula undalis Fabricius, S. litura, Pieris rapae Linn, Artogeia rapae Linn, 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.

Economic Injury levels of Liriomyza trifolii Burgess (Diptera: Agromyzidae) infesting Eggplant in Greenhouse

Economic injury levels and economic thresholds were estimated for the american serpentine leafminer (Liriomyza trifolii) on greenhouse eggplant. Liriomyza trifolii density was increased until the late June and decreased after the July in innoculation on may 17. Growth of an aerial plants and fruits were not different in treatment respectively. But total number of fruits and yields were decreased on higher inoculation density. Whereas the rate of yield loss was increased. The rates of damaged leaf by L. trifolii were increased on higher inoculation density and the peak was 65%. The number of commodity fruits and the rates of commodity fruit were become lower than non-treatment (72.2%). The rates of damaged leaf area were 5.3, 11.7, 19.7, 25.7% on inoculation densities and the rates of yield loss were 0.6, 4.8, 9.8, 14.7%, respectively. There existed close correlation between rate of yield loss and inoculation density (Y

Temperature-dependent Development Model of Hawaiian Beet Webworm Spoladea recurvalis Fabricius (Lepidoptera: Pyraustinae)

The Hawaiian beet webworm (Spoladea recurvalis) is one of the serious insect pests found on red beet (Beta vulgaris var. conditiva) in Korea. The study was conducted to investigate the development period of S. recurvalis at various constant temperatures, 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, 32.5 and , with RH and a photoperiod of 16L:8D. The developmental period from egg to pre-adult was 51.0 days at and 14.6 days at . The developmental period of S. recurvalis was decreased with increasing temperature. The relationship between the developmental rate and temperature was fitted well by linear regression analysis (). The lower developmental threshold and effective accumulative temperature of the total immature stage were and 384.7 degree days, respectively. The nonlinear relationship between the temperature and developmental rate was well described by the Lactin model. The relationship between the cumulative frequency and normalized distributions of the developmental period for each life stage were fitted to the Weibull function with

Occurrence of Insect Pests in Rubus coreanus Miquel

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Seasonal occurrence of Tetranychus kanzawai and control efficacy of alternate use of natural enemy and miticide in Rubus coreanus field.

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.

Life Table Analysis of the Cabbage Aphide, Brevicoryne brassicae (Linnaeus) (Homoptera: Aphididae), on Tah Tsai Chinese Cabbages

Seasonal occurrence and suitable time of control of Tetranychus kanzawai along with the control efficacy of the alternative use of natural predator and miticide was investigated in Rubus coreanus (Miquel). T. kanzawai appeared in late May with its peak between June and July, and decreased after August in R. coreanus. In Iksan, T. kanzawai estimates show peaks 2~4 times per year during the investigation periods from 2006 to 2008 in R. coreanus fields. Suitable time of control of T. kanzawai was in early to mid May. And control effects of T. kanzawai was improved with an alternated control plot, treating miticides in early-occurrence of T. kanzawai and then releasing the natural predator (Phytoseiulus persimilis Anthias-Henriot). Also, the yields of R. coreanus was highest in the alternated control plot of 638kg/10a compared to non-treatment of 559kg/10a.

Seasonal Occurrences of Insect Pests in Watermelon under Greenhouses as Affected by Cropping Season

Life table analysis and temperature-dependent development experiments were conducted to understand the biological characteristics of the cabbage aphid, Brevicoryne brassicae (Linnaeus) on detached Tah Tsai Chinese cabbage (Brassica campestris var. narinosa) leaves at seven constant temperatures (15, 18, 21, 24, 27, 30 and ; RH; 16L:8D). Mortality was lowest at with 18% and 0% at and nymphal stages, respectively. The developmental period of nymphal stage was 8.4 days at , and it decreased with increasing temperature. The developmental period of the nymphal stage was 6.7 days at . The lower threshold temperature calculated using a linear model was , and the effective accumulative temperature was 120.1DD. Adult longevity was 14.9 days at , and total fecundity was observed 58.5 at . According to the life table, the net reproduction rate was 47.5 at , and the intrinsic rate of increase and the finite rate of increase were 0.36 and 1.43, respectively, at . The doubling time was 1.95d at , and mean generation time was 7.43d at .

Economic Injury Levels and control threshold of Tetranychus kanzawai Kishida(Acari, Tetranychidae) Infesting Korean black raspberry (Rubus coreanus Miquel)

The seasonal occurrence of insect pests in watermelon cultivated in greenhouses was surveyed in Gochang from 2006 to 2007 considering three seasonal types of culture: forcing culture, semi-forcing culture and retarding culture. Aphis gossypii, mites (Tetranychus urticae+T. kanzawai) and Palpita indica were the most serious pest species in watermelon greenhouse culture. A. gossypii and mites showed high density during the months of June and September in semi-forcing and retarding culture, respectively. Palpita indica was observed only in retarding culture. Leaf damage by Palpita indica was observed from the middle of August and peaked to 79.4% damage in the middle of September. Thrips and whiteflies were captured in high density by the yellow sticky trap in semi-forcing culture and retarding culture but these insects showed low population density in watermelon leaves.

Some Medicinal Plants Suppressed Reproduction of Meloidogyne hapla on Codonopsis lanceolata Trautv

Economic injury levels (EILs) and economic control threshold (ET) were estimated for the Tea red spider mite, Tetranychus kanzawai Kishida(Acari, Tetranychidae) in Rubus coreanus Miquel. T. kanzawai density increased until the early-July and thereafter decreased in all plots except the non-innoculation plot where initial density of the mite were different each 0, 5, 10, 20 and 40 adults per plant branch on May 7 in 2008. And the occurrence of the densities were increased higher innoculated density than different innoculation density. The yield was decreased with increasing initial mite density and thereby the rates of yield loss was increased with increasing initial mite density. And T. kanzawai occurrence density, yields and the rates of yield loss, where initial density of the mite were different each 0, 2, 5, 10 and 20 adults per plant branch on May 8 in 2009 were similar tendency to 2008 year results. The relationship between initial T. kanzawai densities and the yield losses was well described by a linear regression, Y