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.
Keyword: 

Judul: Quantitative analysis of potency of acerophagus papayae noyes & schauff (Hymenoptera: Encyrtidae), parasitoid of the papaya mealybug
Abstrak: The papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), was an invasive pest that invaded Indonesia in early 2008 and caused heavy damage on papaya. One of the natural enemies found in Bogor was parasitoid Acerophagus papayae Noyes and Schauff (Hymenoptera:Encyrtidae). The parasitoid was believed to have been fortuitously introduced into Indonesia. Research was conducted to evaluate the potency of A. papayae as biological control agent for the papaya mealybug. Studies included determining various biological parameters such as development time, host preference, functional response, and simulation model of host-parasitoid population dynamics. Parasitoids were obtained from the papaya fields by collecting the mummy of papaya mealybugs and enclosed individually in gelatin capsules. Adult parasitoids emerged were reared on the papaya mealybugs with Jatropha curcas as a host plant. Fitness and preference of the parasitoids were studied using papaya mealybug instar II dan III with a piece of papaya leaf in a test tube (d = 3 cm, h = 15 cm). Functional response of the parasitoids were studied at the host density of 2, 5, 10, 20, 30, 40, and 50 nymphs. Mummies were also collected from the fields, and the data were used to test the sensitivity and validate the model using Stella version 9.02 software. Our study revealed that the parasitoid preferred second-instar over the third-instar nymphs of P. marginatus. Immature developmental time was shorter and survival rate was higher of parasitoids developed on the second-instar nymps. Female parasitoid showed type II functional response with the increasing host density. Our simulation model indicated that the parasitoid had a good searching capacity and was able to regulate papaya mealybug population.
Keyword: 

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.
Keyword: