Sang-Guei Lee

Seasonal Occurrence and Damage of Bactrocera scutellata (Diptera: Tephritidae) in Jeonbuk Province

The striped fruit fly, Baetrocera scutellata (Diptera: Tephritidae), is one of the most important pests in Cucurbitaceae plants. Among 6 attractants for B. scutellata used, Cue-lure was shown better effect than the others. Newly emerged adult of B. scutellata had been occurred early June of the year tested. There were two peaks of occurrences of B. scutellata, one was from mid-July to early August and the other was early September suggesting that B. scutellata has two generation a year. The larva of B. seutellata damaging the female flower and stem of the pumpkin was found for the frist time on Korea. The blossoms were damaged and fallen by B. scutellata which were 53.8% of male flower and 30.7% of female flower in the 6 pumpkins. The pumpkin flowers were damaged 51.9% by B. scutellata. Especially thc pumpkin flowers damaged were shown 72.7% (1015/1397 individuals) from August to September. The larva of B. scutellata was found from the Trichosanthes kirilowii on 24 June 2009 in Jinan-gun Jeollabuk-do.

Insecticidal activities of their components derived from the essential oils of Cinnamomum sp. barks and against Ricania sp. (Homoptera: Ricaniidae), a newly recorded pest

BACKGROUND Insecticidal activities of Cinnamomum cassia and Cinnamomum zeylanicum oils and their components are not known against Ricania sp. Insecticidal activities of major components derived from C. cassia and C. zeylanicum oils were examined in spray and leaf-dipping bioassays against Ricania sp. nymphs and adults. RESULTS The LC50 value of C. cassia and C. zeylanicum oils was 37.66 and 72.62 mg L-1 , respectively, in leaf-dipping bioassays against Ricania sp. nymphs, and 77.38 and 134.86 mg L-1 in spray bioassays against Ricania sp. adults. The insecticidal activity of C. cassia oil was 1.74-1.93 times greater than that of C. zeylanicum oil. When examined by gas chromatography mass spectrometry, the cinnamaldehyde content of C. cassia and C. zeylanicum oils was 80.20% and 46.32%, respectively. Based on the LC50 values of cinnamaldehyde, hydrocinnamaldehyde and 4-hydroxy-3-methoxycinnamaldehyde against Ricania sp. nymphs and adults, cinnamaldehyde (LC50 , 31.25 and 62.43 mg L-1 ) demonstrated the most potent insecticidal activity, followed by 4-hydroxy-3-methoxycinnamaldehyde (172.19 and 212.77 mg L-1 ) and hydrocinnamaldehyde (275.05 and 318.63 mg L-1 ). CONCLUSION The findings revealed that C. cassia oil, C. zeylanicum oil and cinnamaldehyde have potential value in the management of Ricania sp. and could be valuable as effective insecticides.

Temperature-dependent Development Model of the Striped Fruit Fly, Bactrocera scutellata (Hendel)(Diptera: Tephritidae)

The striped fruit fly, Bactrocera scutellata, damages pumpkin and other cucurbitaceous plants. The developmental period of each stage was measured at seven constant temperatures (15, 18, 21, 24, 27, 30, and ). The developmental time of eggs ranged from 4.2 days at to 0.9 days at . The developmental period of larvae was 4.2 days at , and slowed in temperatures above . The developmental period of pupa was 21.5 days at and 7.6 days at . The mortality of eggs was 17.1% at and 22.9% at , Larval mortalities (1st, 2nd, 3rd) were 24.1, 27.3 and 18.2%, respectively, at , Pupal mortalities were 18.2% at and 23.1% at . The relationship between developmental rate and temperature fit both a linear model and a nonlinear model. The lower threshold temperatures of eggs, larvae, and pupae were 12.5, 10.7, and , respectively, and threshold temperature of the total immature period was . The thermal constants required to complete the egg, larval, and pupal stages were 33.2, 118.3, and 181.2 DD, respectively. The distribution of each development stages was described by a 3-parameter Weibull function.

Isolation of Insecticidal Constituent from Ruta graveolens and Structure-Activity Relationship Studies against Stored-Food Pests (Coleoptera)

Isolates from essential oil extracted from the flowers and leaves of Ruta graveolens and commercial phenolic analogs were evaluated using fumigant and contact toxicity bioassays against adults of the stored-food pests Sitophilus zeamais, Sitophilus oryzae, and Lasioderma serricorne. The insecticidal activity of these compounds was then compared with that of the synthetic insecticide dichlorvos. To investigate the structure-activity relationships, the activity of 2-isopropyl-5-methylphenol and its analogs was examined against these stored-food pests. Based on the 50% lethal dose, the most toxic compound against S. zeamais was 3-isopropylephenol, followed by 2-isopropylphenol, 4-isopropylphenol, 5-isopropyl-2-methylphenol, 2-isopropyl-5-methylphenol, 3-methylphenol, and 2-methylphenol. Similar results were observed with phenolic compounds against S. oryzae. However, when 2-isopropyl-5-methylphenol isolated from R. graveolens oil and its structurally related analogs were used against L. serricorne, little or no insecticidal activity was found regardless of bioassay. These results indicate that introducing and changing the positions of functional groups in the phenol skeleton have an important effect on insecticidal activity of these compounds against stored-food pests.

Temperature-dependent Development Model of White Backed Planthopper (WBPH), Sogatella furcifera (Horvath) (Homoptera: Delphacidae)

The developmental times of the immature stages of Sogatella furcifera (Horvath) were investigated at ten constant temperatures (12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, ), 20~30% RH, and a photoperiod of 14:10 (L:D) h. Eggs were successfully developed on each tested temperature regimes except and its developmental time was longest at (22.5 days) and shortest at (5.5 days). Nymphs successfully developed to the adult stage from to temperature regimes. Developmental time was longest at (51.9 days) and it was decreased with increasing temperature up to (9.0 days). The relationships between developmental rate and temperature were fitted by a linear model and seven nonlinear models (Analytis, Briere 1, 2, Lactin 2, Logan 6, Performance and modified Sharpe & DeMichele). The lower threshold temperature of egg and total nymphal stage was and respectively. The thermal constant required to complete egg and nymphal stage were 122.0 and 156.3 DD, respectively. The Briere 1 model was best fitted (

Fumigant Toxicity and the Repellent Effect of Essential Oils against Sitophilus zeamais Motschulsky

Stored grain insects appear frequently as grains are harvested, stored, and distributed on the market. Producers mostly depend on chemical fumigants to control and repel insect pests, but this application of chemicals may cause side effects for humans and the environment. Safer control approaches, including the use of natural products are required, and in this study, we assessed the control effect of essential oils on stored grain insects. The essential oils of 8 plant species from 6 families were tested for their fumigant toxicity and repellent effects using a Y-tube Olfactometer against Sitophilus zeamais adults. Pennyroyal and tea tree oil respectively exhibited 97% and 63% mortality at air concentration in tested fumigant toxicity. Of particular note, pennyroyal oil (, hour

Repellent and Acaricidal Activities against Leptotrombidium pallidum Larvae of Eucalyptus Oil

Repellent and acaricidal activities of eucalyptus oil, permethrin, and DEET against Leptotrombidium pallidum larvae, which are a vector transmitting tsutsugamushi disease, were evaluated under laboratory conditions using a filter paper impregnated method. The values of eucalyptus oil and DEET were 0.025 and 0.018 , respectively while that of permethrin was higher than 0.2 . In the repellency test of these materials at 6.14 , eucalyptus oil gave complete repellency, and the larvae crossed the treated zone killed. But permethrin showed 60% repellency at 9.20 and the mites croosed the zone were not killed. The percent repellency of DEET at 0.53 was 8.3 and 2.8 times higher than that of permethrin and eucalyptus oil, respectively. The acaricidal activities of emulsifiable concentrates-pump sprayers containing the eucalyptus oil as an active ingredient were assayed. The emulsifiable concentrates containing 1% and 3% eucalyptus oil showed weak mortality at 1 hour after treatment, while all ones containing more than 6% oil produced 100% activity against L. pallidum larvae. The mortality also increased as exposure time to the concentrates increase. These results suggest that the potential of eucalyptus oil highly expected to be used as a control or repellent agent against L. pallidum larvae may be very high.

Construction and Evaluation of Cohort Based Model for Predicting Population Dynamics of Riptortus pedestris (Fabricicus) (Hemiptera: Alydidae) Using DYMEX

ABSTRACT: A Cohort based model for temperature-dependent population dynacmics of Riptortus pedestris was constructed by usinga commercial software (DYMEX) and seasonal occurrence along with pesticide treatments effect was simulated and validated with pheromone trap data. Ten modules of DYMEX software were used to construct the model and Lifecycle module was consisted of seve ndevelopmental stages (egg, 1 - 5 nymphal instars, and adult) of R. pedestirs . Simulated peaks of adult populations occurred three or fou rtimes after the peak of overwintered populations which was similar to those observed from pheromone trap catch. Estimated dates forthe second peak were quite similar (1-2 day difference) with those observed with pheromone trap. However, the estimated dates f or thefirst population peak were 9-16 days later than the observed dates by pheromone trap and the estimated dates for the last peak were 17-2 3days earlier than the observed dates. When insecticide treatments were included in the simulation, the biggest decrease in R. pedestris adult density occurred when insecticide was applied on July 1 for the first peak population: the estimated adult density of the second pea k was 3% of untreated population density. When insecticide was assumed to be applied on August 30 for the second peak population, theestimated adult density of the following generation was about 25% of untreated population and the peak density of the following generation reached about two weeks later than untreated population. These results can be used for the efficient management stra tegies for the populations of R. pedestris.Key words: Riptortus pedestris, DYMEX, Population dynamics model, Simulation초 록: 온도에 따른 톱다리개미허리노린재 (Riptortus pedestris)의 개체군 밀도 변동 예측 모델을 상용 소프트웨어인 DYMEX로 구축하고 월동 성충밀도를 바탕으로 한 연간 발생 밀도 변동 패턴과 살충제 처리 시기에 따른 밀도 억제 효과를 시뮬레이션하였다 . 구축된 모델은 총 10개의 모듈을사용하였으며, Lifecycle 모듈은 알, 1, 2, 3, 4, 5령, 성충의 7개 발육 단계로 구성하였다. 월동 성충 개체군의 포획시기를 이용하여 연중 밀도 변동을 예측한 결과 연도에 따라 3~4번의 신 성충 발생이 가능하여 페로몬 트랩 포획밀도 조사와 유사하였다. 콩 포장으로 침입해 들어오는 두 번째 신성충의 경우 개발된 모델을 이용하여 예측된 성충 발생 최성일이 페로몬 트랩으로 조사된 포획 밀도 최성기와 거의 일치 하였다 . 그러나 예측된 첫 번째 신 성충 발생 최성일은 페로몬트랩 포획 최성기보다 연도에 따라 9~16일 늦었으며, 마지막 세대의 발생 최성일은 연도에 따라 페로몬 트랩 포획 최성기보다 17~23일 빨랐다. 살충제 사용을 가정한 첫 번째 신성충 개체군 밀도 억제가 다음 세대들의 밀도 증가에 미치는 영향을 시뮬레이션 한 결과, 신 성충 발생 초기일수록 밀도 억제효과가 커서 7월 1일 살충제 처리를 가정하였을 때 다음 세대에 형성된 성충은 무처리의 3% 정도로 현저하게 낮았다. 또한 포장에 침입해 들어오는 두 번째 신성충 개체군을 대상으로 시기별 살충제 처리 효과를 시뮬레이션한 결과 8월 30일 살충제 처리를 가정한 경우 다음세대 성충 최고 밀도는 무처리의 25% 정도로 줄었고, 최고 밀도에 도달한 시기도 무처리에 비해 2주 이상 늦었다. 이상의 연구 결과들은 톱다리개미허리노린재의 효율적인 종합적 방제 계획을 세우는데 유용하게 사용될 수 있을 것으로 기대된다 .검색어: 톱다리개미허리노린재, DYMEX, 개체군 밀도변동 모델, 시뮬레이션*Corresponding author: changgpark@korea.krReceived February 10 2015; Revised March 30 2015Accepted April 15 2015

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

Prediction of Adult Emergence Time and Generation Number of Overwintered Small Brown Planthopper, Laodelphax striatellus According to RCP8.5 Climate Change Scenario

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