Tae-Heung Kim

High-brightness gallium nitride nanowire UV–blue light emitting diodes

We report on high-brightness GaN nanowire UV–blue light emitting diodes (LEDs), which are fabricated by coupling of n-GaN nanowires and p-GaN substrates using two assembly methods, random dispersion (RD) and dielectrophoresis assisted assembly deposition (DAAD). These GaN nanowire LEDs have bright UV–blue emission (411–437 nm) from the n-GaN nanowire/p-GaN substrate junction and the light emission is strong enough to be observed with the naked eye even for a single GaN nanowire LED. The results reported here should have significant implications for the fabrication of highly efficient, low-cost UV–blue LEDs with low power consumption, as compared to conventional thin-film based GaN LEDs.

Molecular Genetic Diagnosis of Four Fruit Fly Species (Tephritidae)

Abstract The true fruit flies (Diptera: Tephritidae) are major agricultural pests worldwide. In Korea, imported crops are carefully scrutinized to prevent infestation by exotic tephritids and rapid species identification is required to make quarantine decisions. At quarantine checkpoints, tephritids are most commonly intercepted at the larval stage, however larvae have few diagnostic morphological features. Here we describe a molecular genetic method using restriction enzyme digestions of PCR products from the mitochondrial gene, cytochrome oxidase I (COI). This technique provides a simple diagnostic marker for Korean fruit flies in the genus Bactrocera (B. depressa, pumpkin fruit fly; and B. scutellata, pumpkin flower fruit fly) and wide spread fruit flies (B. dorsalis, oriental fruit fly; and Ceratitis capitata, medfly). The restriction enzymes ApaI, NheI and SacI were used to digest the 815 bp PCR product into fragments that uniquely diagnose each species. The simplicity and relatively low cost of this molecular approach will facilitate rapid quarantine decisions concerning exotic fruit flies.

Effect of Temperature on Development and Life Table Parameters of Tetranychus urticae Koch (Acari: Tetranychide) Reared on Eggplants

Temperature dependent development of Tetranychus. urticae Koch was studied on the leaf of eggplant at 17, 22, 27, 32 and . T. urticae showed a minimum mortality at and it increased at higher or lower temperatures than . The hatchability was low at 17 and . The duration of development decreased with increasing temperatures i.e., 5.3d at and 25.8d at . Linear regression analysis of temperature vs. rate of development yielded the higher resulting in a good fit of the estimated line in the range of . Developmental zero temperature was for the entire immature stage of female and for that of male. Thermal constants were 80.5 and 74.7 degree days for those of female and male, respectively. Adult life span and oviposition period decreased with increasing temperatures. The number of eggs laid per female peaked at 141.0 eggs at , while that was a minimum 78.0 eggs at . Rate of hatchability, ratio of female, and were increased up to , and than declined thereafter. Intrinsic rate of natural increase (Rm) increased with rising temperatures and showed a maximum 0.5652 at . Also, increased with increasing temperature. Doubling time (Dt) and generation time (T) decreased with increasing temperature.

Development under Constant Temperatures and Seasonal Prevalence in Soybean Field of the Bean Pyralid, Omiodes indicatus (Lepidoptera: Crambidae)

The bean pyralid, Omiodes indicatus (Fabricius), moulted 4 times during larval period. When temperature increased from 15 to 20, 25, and , the developmental period of immature stages was shortened; 18.2, 7.5, 5.0, and 4.1 days of egg period; 51.8, 20.0, 12.7, and 9.9 days of larval period; 29.5, 12.0, 8.0, and 5.9 days of pupal period, respectively. Adult longevity was 16.0, 14.7, 11.2, and 7.5 days at respective temperatures. A female adult layed 57.0, 63.3, 82.2, and 31.7 eggs in 3.7, 6.0, 5.8, and 3.0 days of oviposition period at the same temperature regimes, respectively. Field survey in 2006 and 2007 showed that leaf damage on paddy field and upland soybeans began to appear in mid July, reaching its peaks in mid August and late September. Adults of the bean pyralid appeared in mid July and peaked in late August and early October.

Mating Behavior of the Pumpkin Fruit Fly [Bactrocera (Paradacus) depressa (Shiraki)] in a Field Cage

ABSTRACT : Field collected larvae inside the pumpkin fruit in Jinan, Chonbuk Province were kept in the laboratory at 24±2℃, RH 65±5%, and 14L:10D until they pupated and eclosed. Adults were fed with dry-milk based diet. Mating behavior was observed when they were 40 days old in a field cage at dusk in July and October, 2008. Wing vibration in male took place under the light intensity of 200 lux-20 lux, however, most commonly under 30 lux. Mounting between male and female was observed under 150 lux-30 lux after the act of wing vibration, also most frequently under 30 lux. Copulation occurred under 150 lux-20 lux. Females approached face to face to males which had been engaged in wing vibration and the copulation was successful for up to 64%. Copulation never occurred when a female positioned in front or at side of the male that was not engaged in wing vibration. KEY WORDS : Pumpkin fruit fly, Wing vibration, Mounting, Copulation초록 : 호박과실파리의 유충은 전북 완주군 진안의 호박 피해과에서 채집하였다 . 실내 사육실 24±2℃, RH 65±5%, 14L:10D에서 용화를 유도하였으며 번데기에서 우화한 성충은 전지분유를 기본으로 한 diet를 제공하였다. 호박과실파리 짝짓기 관련 행동의 관찰은 우화 후 40일의 암, 수 성충을 대상으로 야외 케이지를 이용하여 2008년 7월과 10월 초 오후 자연광 아래에서 실시하였다. 성충 수컷 날개 떨림의 광 조건은 200 lux-20 lux였고, 30 lux에서 활발하였다. 날개 떨림 후 성충 암, 수의 올라타기는 150 lux-30 lux 사이에서 관찰 되었으며, 올라타기도 30 lux에서 빈도가 높았다. 교미의 경우 올라타기 광 조건과 유사한 150 lux-20 lux에서 관찰되었다. 날개 떨림 중의 수컷은 암컷과 교미 성공률이 64% 수준으로 날개 떨림 행동을 통해 이끌려 날아온 암컷이 수컷의 앞쪽에 있을 때 대부분 교미가 이루어졌다 . 날개 떨림을 하지 않은 경우 앞쪽 , 옆쪽, 그리고 어느 쪽에 암컷이 있어도 교미가 이루어지지 않았다 .검색어 : 호박과실파리, 날개 떨림, 올라타기, 교미

Life Table of the Greenbug, Schizaphis graminum (Rondani) (Homoptera: Aphididae) on Barley, Hordeum vulgare L.

To construct a life table and development model Schizaphis graminum (Rondani), its adult longevity and fecundity were studied at various constant temperatures ranging from 15 to , with RH, and a photoperiod of 16L:8D. Adult longevity of the greenbug gradually increased with decreasing temperature below . Total fecundity was not significantly different at all temperatures except at . Daily fecundity gradually increased from . It was 3.6 at and as temperatures either went down or up, it decreased to 1.4 at and 0.4 at Net reproduction rate (Ro) was highest with 47.6 at . The intrinsic rate of increase per day and the finite rate of increase per day were highest with 0.4 and 1.5 at , respectively and the doubling time (Dt) was shortest with 0.98 at . The mean generation time (T) was 8.41 at

Temperature-dependent Development and Its Model of the Greenbug, Schizaphis graminum (Rondani) (Homoptera: Aphididae)

The development of Schizaphis graminum (Rondani) was studied at various constant temperatures ranging from 15 to , with RH, and a photoperiod of 16L:8D. Mortality of the stage nymphs were similar at most temperature ranges while at high temperature of , more stage individuals died. The total developmental time ranged from 13.8 days at to 4.9 days at suggesting that the higher the temperature, the faster the development. However, at higher end temperature of the development took 6.4 days. The lower developmental threshold temperature and effective accumulative temperatures for the total immature stage were and 105.9 day-degrees, respectively and the nonlinear shape of temperature related development was well described by the modified Sharpe and DeMichele model. The normalized cumulative frequency distributions of developmental period for each life stage were fitted to the three-parameter Weibull function. The attendance of shortened developmental times was apparent with nymph, and total nymph stages in descending order. The coefficient of determination ranged between 0.80 and 0.87.

Bionomics of Tetranychus urticae Koch on Eggplants under Various Nitrogen Regimes in Controlled Environment

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with nitrogen contents of 5 mM, 10 mM, 30 mM, and 60 mM. As the nitrogen level in hydroponics increased, it also increased in the plant whereas that of K, Ca, and Mg decreased. More nitrogen in hydroponics resulted in increased contents of water and crude protein, and decreased ash, carbohydrates, and fibers within the plant. Biomass was the heaviest as 989.5 g at 10 mM and the lightest at 60 mM. Leaf thickness and the content of chlorophyll increased as the content of nitrogen increased. Laboratory leaf disc tests obtained from plants grown at various nitrogen levels revealed that feeding and oviposition preferences of T. urticae were high at 30 mM and low at 5 mM. Ratio of damaged leaf by naturally occurring T. urticae on eggplants of 99 days post-transplant in the greenhouse was the highest as 98% at 60 mM. Degrees of damage on eggplants with and without T. urticae infestation turned up more as the differences in the levels of nitrogen in the hydroponics get bigger. No definite differences in the rate of T. urticae development was found between nitrogen treatment levels but, mortalities in immature stages dropped as the nitrogen levels went up. Adult longevity was the longest of 11.9 for female and 6.9 days for male at 60 mM. Oviposition period was also the longest as 11.7 days at 60 mM and shortened as the level of nitrogen decreased. The number of eggs oviposited was the most as 144.4 at 60 mM while it was the least as 41.0 at 5 mM. Sex ratio was 0.75 in favor of female at 10 mM. and T increased, no trends were detected in , while Dt decreased as the levels of nitrogen went up.

Effects of Temperature on the Development of Tropidothorax cruciger (Hemiptera: Lygaeidae) on Cynanchum wilfordii

Abstract Tropidothorax cruciger (Motschulsky) was reared on buds and leaves of Cynanchum wilfordii Hemsley at constant temperatures of 15, 18, 23, 28, and 33±1°C in the laboratory. Eggs of T. cruciger did not hatch at 15°C. Egg periods were 21.9, 14.2, 8.5, and 7.8 days at 18, 23, 28, and 33°C, respectively. Nymphal periods were 69.4, 52.6, 30.5, and 20.2 days, and egg to adult emergence periods were 91.3, 66.8, 39.0, and 28.0 days at 18, 23, 28, and 33°C, respectively. Theoretical developmental threshold (DT) temperatures of T. cruciger were 10.1 and 13.3°C for egg and nymph stages, respectively. When the egg and nymphal stadia were pooled, the DT temperature turned out to be 12.6°C. Accumulated effective temperatures (ET) for stages of egg, nymph, and egg-nymph combined were 171.8, 420.7, and 589.9 day-degrees, respectively. Longevity of adults was 47.8, 54.4, 31.9, and 18.5 days, respectively, the longest being at 23°C. Pre-ovipositional periods were 38.5, 43.0, 26.3, and 17.4 days and the number of eggs laid per female was 27.8, 34.0, 30.8, and 23.4 at the above temperatures, respectively. The rates of hatching were 35.6, 85.1, 68.1, and 39.4%, respectively at the temperatures previously given.

Bionomics, Damage Assesment and Management of Tetranychid Mites on Perennial Herbs

Abstract This study searched for biological and agricultural bases necessary in formulating suppressive measures of herbaceous mites occurring on perennial herbs in Korea. Of those tetranychids, the tea red spider mite (TRSM), Tetranychus kanzawai Kishida, mainly attacked the perennials and was believed to be of economic importance. Its annual abundances on 3 different herbs are presented and for Codonopsis lanceolata various injury levels in leaf are related to loss of chlorophyll and root yield. And of 4 species of predaceous phytoseiids identified from the field, Amblyseius makuwa and Amblyseius obtuserellus were quite common and regarded as possible density control agents for tetranychid mites. Together with a review on pest control measures conventionally practiced by the local farmers, several cultural and biological tactics are discussed to help formulate a safe and sound integrated management program against TRSM on perennial herbs.