Judul: Biologi perkembangan dan neraca hayati kutu putih pepaya, Paracoccus marginatus (Williams and Granara de Willink) (Hemiptera: Pseudococcidae) pada tiga jenis tumbuhan inang
Abstrak: The papaya mealybug, Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae), has been considered as a new invasive pest causing heavy damage on papaya in Indonesia since 2008. The pest is polyphagous with more than 55 host plant species. Study was conducted in laboratory with the objectives to determine developmental biology and life table parameters of the mealybug feeding on papaya, physic nut, and cassava leaves. Host plant species affected papaya mealybug performances. Egg stage lasted 7,25, 8,09, and 9,86 d on papaya, physic nut, and cassava, respectively. The shortest female nymphal developmental time was on papaya (18,91 d) and the longest on cassava (32,45 d). Longevity of adult males ranged from 1,09-2,85 d while females 12,29-14,93 d, respectively. When the mealybugs were reared on a seedling, the fecundity was higher on papaya (324,6) than those of physic nut (186,6) and cassava (157,5). No egg production occurred in virgin females. The sex ratio of P. marginatus favoured females, which comprised about 90% of population on papaya and cassava. The intrinsic rate of increase (rm) was significantly different among hosts, with the highest rate (0,117 female offspring/female/d) occured on papaya, followed by physic nut (0,079) and cassava (0,057). The maximum values of rm along with net reproductive rate (Ro) and finite rate of increase (λ), and the shortest mean generation time (T) and doubling time (DT) on papaya, indicating that papaya was the most favorable host plant for P. marginatus.
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Judul: Neraca hayati dan pemangsaan curinus coeruleus mulsant (Coleoptera:Coccinellidae) pada kutu putih tanaman pepaya paracoccus marginatus williams
Abstrak: Papaya mealybug, Paracoccus marginatus, is a new invasive pest causing heavy damage on papaya in Indonesia since 2008. One of its natural enemies found in the field was a lady beetle Curinus coeruleus.Studies were conducted in laboratory with the objectives to determine life history and life table parameters as well as predation rate on the papaya mealybug. Our studies revealed that eggs of C. coeruleus hatched in 7,00 days. Development of larval instar I took 6,06 days, instar II 5,5 days, instar III 6,11 days, and instar IV 8, 43 days. The pupal stage was 6,66 days. The longevity of male adult was 49,08 days, while of female was 76,99 days.
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Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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