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Pohang, South Korea

Kim D.-S.,Jeju National University | Seo Y.D.,Hankook Life Science Institute | Choi K.S.,National Institute of Horticultural and Herbal Science
Journal of Asia-Pacific Entomology | Year: 2010

Arrowhead scale (AHS), Unaspis yanonensis (Kuwana) (Hemiptera: Diaspididae), and pink citrus rust mite (PCRM), Aculops pelekassi (Keifer) (Acari: Eriophyoidae), are important arthropod pests of organic citrus orchards in Jeju. This study was conducted to evaluate the stage-specific mortality effects of petroleum spray oil (PSO) (AI 95%) and lime sulfur (LSF) (AI 22%) against AHS and PCRM in the laboratory. The developmental stages of AHS were divided into the 1st nymph, the three sub-stages of the 2nd nymph (N2a = early soft body, N2b = hardened body, and N2c = late apolysis), and the two sub-stages of adult females (A3a = early age, and A3b = middle age). The developmental stages of PCRM were divided into eggs, the 2nd nymphs, and adults. PSO 100× and LSF 80× resulted in high mortality against the 1st nymphs of AHS. The effects of PSO and LSF were significantly different among the application rates on 2nd nymphs of AHS and were higher on N2a. The PSO and LSF treatments significantly affected egg hatch rate of PCRM: LSF 50× (2.4%), LSF 100× and PSO of 50× and 200× (17.8% to 20.4%), and LSF 200× (39.0%). PSO and LSF also significantly affected the mortality of the 2nd nymphs and adults of PCRM. PSO and LSF resulted in low direct mortality on A3a and A3b of AHS, but induced an abnormal morphology. PSO treatment resulted in a loose attachment of AHS scale cover on the leaf surface and LSF treatment resulted in an abnormal or lacking scale cover. © 2010 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Source

Seo Y.D.,Hankook Life Science Institute | Kim D.-S.,Jeju National University
Journal of Asia-Pacific Entomology | Year: 2014

This study was carried out to develop temperature-driven models for immature development and oviposition of the pink citrus rust mite Aculops pelekassi (Keifer). A. pelekassi egg development times decreased as the temperature increased, ranging from 6.6. days at 16. °C to 1.9. days at 35. °C. Total nymph development times decreased from 8.2. days at 16. °C to 3.3. days at 35. °C. The egg-to-adult development durations were 14.8, 11.6, 9.7, 8.0, 7.3, 6.1, and 5.2. days at 16, 20, 24, 26, 28, 32, and 35. °C, respectively. The lower developmental threshold temperatures for eggs, nymphs, and total egg-to-adult development were calculated as 9.3, 4.3, and 6.9. °C, respectively. The thermal constants were 54.0, 101.8, and 153.8. degree days for each of the above stages. The non-linear biophysical model fitted well for the relationship between the development rate and temperature for all stages. The Weibull function provided a good fit for the distribution of development times of each stage. Temperature affected the longevity and fecundity of A. pelekassi. Adult longevity decreased as the temperature increased and ranged from 24.2. days at 16. °C to 14.6. days at 35.0. °C. A. pelekassi had a maximum fecundity of 33.1 eggs per female at 28. °C, which declined to 18.8 eggs per female at 16. °C. In addition, three temperature-dependent components for an oviposition model of A. pelekassi were developed with sub-models estimated: total fecundity, age-specific cumulative oviposition rate, and age-specific survival rate. The oviposition model, coupled with the stage emergence model, should be useful to construct a population model for A. pelekassi in the future. © 2013 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Source

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