• Korean journal of applied entomology
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• v.42 no.3
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• pp.197-201
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• 2003

These studies were carried out to investigate the amounts and preferences of Oligota kashmirica benefica to 3 species of phytophagous mites and cannibalism. The number of mites consumed by an adult beetle tended to increase as prey density and temperature go up. In the constant temperature of 25$^{\circ}C$, average number of consumed adult mites by an adult of O. kashmirica benefica to Panonychus citri, Tetranychus urticae and T. kanzawai were 21.9, 13.5, and 14.1 for a day, respectively. The number of mites consumed by larva of O, kashmirica benefica tended to increase as the larva grow up. First, 2nd and 3rd larva of the beetle consumed 2.8, 11.2 and 25.4 adult of citrus red mite (P. citri) for a day, respectively. Total number of mites consumed during larval stage (5 days, 25$^{\circ}C$) to P. citri, T. urticae and T. kanzawai were 77.7, 61.3 and 73.0, respectively. The larva and adult beetle did not prefer specific species in the P. citri, T. urticae and T. kanzawai, and when there was no diet, few incidents of cannibalism between different developmental stage were observed.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.150-154
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• 2005

To overcome the problems associated with chemical pesticides, biological pest controls agent extracted from Ginkgo biloba was studied. Insecticidal activities components in Ginkgo biloba extracts were analyzed using high performance liquid chromatography (HPLC). This results of HPLC analysis, GG-W80 were included bilobalide $611\;{\mu}g/kg$, ginkgolide A $37\;{\mu}g/kg$ and ginkgolide B $243\;{\mu}g/kg$, while YG-W80 were included bilobalide $214\;{\mu}g/kg$ and ginkgolide B $46\;{\mu}g/kg$. The biological activity of Ginkgo biloba extracts were conducted to repellent and pesticidial effect of Tetranichus urticae, Aphis gossypii and Myzus persicae treated with Ginkgo biloba leaves extracts. Mortalities of adult T. urticae to green Ginkgo biloba extracts (GG-W80) and yellow Ginkgo biloba extracts (YG-W80) were shown 98.3% and 20.0%, respectively. From these results, terpenes components in Ginkgo biloba extracts could be use for biological controls for T. urticae.

• Korean journal of applied entomology
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• v.40 no.4
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• pp.321-326
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• 2001

Contribution of Wolbachia infection to fitness of a species (developmental time, adult life span, fecundity and ovipositional period) was measured in the susceptible and dicofol-resistant strains of two spotted spider mite, Tetranychus urticae Koch, on miniature roses. Based on ftsZPCR assay, Wolbachia infection was confirmed only in the susceptible strain. The susceptible strain had significantly higher fecundity (eggs/female) and shorter developmental times than the resistant strain. Longer adult life span and ovipositional period were observed in the susceptible strain. Fitness differences were appeared to influence dicofol resistance development. Similar measurements were performed with progeny from two reciprocal $F_1$crosses. Similar to other examples of cytoplasmic incompatibility induced by Wolbachia, subsequent cross between uninfected female and infected male spider mites were different from the other combination: a high egg mortality and a male-biased sex ratio. When the intrinsic rate of natural increase was calculated, the cross between uninfected female and infected male spider mites had a significantly lower rate($0.09\pm$0.01) than did the other combination ($0.20\pm$0.01). These results suggest that the dynamic and evolution of the fitness are closely associated with dicofol resistance and Wolbachia infection in the two spotted spider mites.

• Research in Plant Disease
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• v.24 no.4
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• pp.257-264
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• 2018

Hydroponic strawberry culture system is increasing annually. Most of strawberry farmers use mulched bed in hydroponic culture and strawberry plants were transplanted in early September. After transplanting, Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae and twospotted spider mite (TSSM), Tetranychus urticae, can increase their occurrence under high temperature condition. Therefore, we conducted for comparison occurrence of Fusarium wilt and TSSM on mulched with green polyethylene film and non-mulched bed. Occurrence of Fusarium wilt on mulched bed was started from early October and more increase than non-mulched bed. Damage rate of TSSM on mulched bed was shown higher than non-mulched bed. Temperature of substrate in mulched bed increased than non-mulched bed, but relative humidity near plants was decreased. As a result, use of non-mulched bed should be effective for reducing of Fusarium wilt and TSSM on strawberry plants.

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.185-188
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• 2004

Feltiella acarisuga Vallot, a predatory gall midge preying upon spider mites, is reported for the first time in Korea. It was found in a greenhouse on Glycine soja Sieb. et Zucc. heavily infested with Tetranychus urticae in Sachon, Kyongnam Province. This species is very useful biological control agent for spider mites on greenhouse vegetable crops. Brief morphological characteristics are described.

• Korean journal of applied entomology
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• v.34 no.1
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• pp.40-45
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• 1995

Eight field-collected populations of the two-spotted spider mites, Tetranychus urticae (Koch) from apple orchards of different geographical areas were tested for resistance to seven acaricides by leaf disk method in comparison with a susceptible strain. Marked regional variations of susceptibility were observed. Only low to moderate resistance to azocyclotin, fenpropathrin, propargite, and abamectin was obtained. However, high resistance to dicofol, fenpyroxymate, and pyridaen by eight field-collected populations was produced. Resistance to dicofol and fenpyroxymate was widespread. All of the strains tested were susceptible to one or more o the acaricides used. These results indicate that careful selection of the chemical used against any population of the two-spotted spider mite might result in satisfactory control.

• Journal of Life Science
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• v.13 no.2
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• pp.150-153
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• 2003

To determine the effect of newly developed insecticide on two spotted spider mite, Tetranychus Urticae, populations, ten leaf discs were sprayed with three different concentrations (0.5%, 1.0%, and 1.5%) of the tested insecticide solution, and with a water-sprayed control. The tested insecticide solution was toxic to adult female and immature of two spotted spider mite, but was relatively non-toxic to eggs. For equivalent concentrations, more adult females were killed than immature stages. There was no marked difference between the hatch of treated and untreated eggs, although a weak trend between the numbers of unhatched eggs and the insecticide concentration after 7 days is shown.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.351-357
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• 2015

The two-spotted spider mite Tetranychus urticae Koch, overwinters in apple culture areas of apple orchards. The mite overwinters in various places on the apple trees, usually in groups of 5-15 females. Overwintering females were mostly found in bark crevices with the hibernation cocoons of the oriental fruit moth, Grapholita molesta Busck. They were also found in small crevices of the bark, and in pedicels left after fruit harvesting. Furthermore, overwintering females were found on rough bark at the bases of buds and spurs, on small limbs and twigs, and in limb crevices and forks. Empty scales of dead diaspidids and coccids, as well as cocoons of lacewings and mummies of parasitized aphids sporadically found on trees, were found to be less common overwintering sites for females of the two-spotted spider mite. In two successive years, the mortality of overwintering females was very high, reaching approximately 72 and 80%. This could be due to the low temperature of winter season in Korea and the low cold tolerance of the mite.

• Korean journal of applied entomology
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• v.34 no.1
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• pp.33-39
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• 1995

본문은 가지의 포전시험자료에 근거하여 점박이응애붙이(Tetranichus cinabaruinus(Boisduval))의 밀도와 피해엄중도간의 관계를 검토하였는데 그 결과 응애밀도와 피해엄중도간의 농약을 살포하기전 혹은 응애가 확산하기 전에는 정상관성(r=${0.865}^{\ast}{\ast}$)을 나타냈으나 통상적인 수량적 관계는 나타내지 않았다. 계통적조사에 근거하여 실제피해엄중도(DI) 증가율 model과 실측피해엄중도 model을 작성한 후 그 두 model로 실제피해엄중도 측정 model을 구성하였다. 피해정도를 잘 반영할 수 있는 누적피해일(cumulative damage days, CDD) 개념을 제출하고 그 수학적 model을 세웠다. 누적피해일은 실제피해엄중도곡선아래의 면적으로서 적분으로 표할 수 있는데 그속에 피해의 점차적이며 누적적인 기본 과정이 뒷받침 되어 있지 않다. 여러 가지 피해정도 표기법을 서로 서로 비교한 결과 CDD가 가장 합리적이었고 또한 동일한 생태조건(동지)하에서는 CDD와 DI가 일정한 등가성이 있었다.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2000.10a
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• pp.65-65
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• 2000