Judul: Study of entomopathogenic fungi Lecanicillium lecanii (Zimm.) (Viegas) zare & gams to control pod sucking bug Riptortus linearis (F.) (Hemiptera: alydidae) Egg.
Abstrak: Lecanicillium lecanii (Zimm.) (Viegas) Zare & Gams is one of the most entopathogenic fungi that can be used to control pod sucking bug Riptortus linearis F. (Hemiptera: Alydidae) egg. The effectiveness of fungi were affected by intraspecies virulence, conidia density, host developmental stage, and environmental factors. The purposes of this research are: (1) to study the phisiological character of various L. lecanii isolates and their virulence to pod sucking bug R. linearis egg, (2) to obtain the maximal conidia density of L. lecanii to control different ages of R. linearis eggs, and (3) to study the effect of several vegetable oils as adjuvant to increase the effectiveness of fungi. Among 37 isolates tested, isolates Ll-JTM11, Ll-JTM12, Ll- JTM15, and Ll-TB2 were judged as the most virulent. The fungi that were virulent were isolated from insect cadaver killed by fungi in the field, while fungi isolated from the soil in general did not show high infectivity. The virulent isolates showed higher growth rate, formed wholly colony, produced more conidia than avirulent isolates, had large conidial size up to 6.5 x 2.5 ìm. More than 95% germ tubes of virulent isolates were formed after 12 hours incubation in the water. The conidia density of 108/ml was found as an effective preparation against newly laid and less than one day old insect eggs. During in vitro experiment, peanut, soybean, and coconut oil increased the growth and development of the fungi. The persistence of fungal conidia on the soybean leaf surface could be maintained until seven days after application. Mixing the vegetable oil at concentration 10 ml/l fungal suspension, increased infectivity of the fungi and decreased hatchability of the egg until 20%. Therefore, damage intensity as indicated by sum of spots, empty pods, and weight of grains were reduced. Adding vegetable oil to the fungal preparation, yielded 40% more grain weight as compared to control. Among three vegetable oils tested, the effect of peanut oil was more pronounced than soybean and coconut oil.
Keyword: Virulence, Soybean pod, Vegetable oils, Conidia

Judul: Pengaruh lama penyimpanan berbagai formulasi cendawan entomopatogen Lecanicillium lecanii terhadap telur hama penghisap polong kedelai Riptortus linearis L. (Hemiptera: Alydidae)
Abstrak: The entomopathogenic fungi Lecanicillium lecanii is currently being developed as mycoinsecticide to control the soybean pod sucking bug Riptortus linearis. In the field, without treated in formulation, this bioinsecticide is often unstable. To maintain the viability and infectivity, the fungi must be formulated by adding certain additives. The aim of the research is to study the viability and infectivity of the fungi after storage in several formulations. The fungi were mixed with (1) talcum powder (2) sweet potato powder (3) cassava powder (4) rice powder (5) corn powder (6) molasses (7) peanut oil (8) soybean oil as treatment and (9) water as control, and stored in the room condition. The viability of the conidia as indicated by germination in water after 10 hours, the growth of fungal colony in 4 to 7 days after being inoculated on PDA media, and infectivity to R. linearis eggs were observed each month during 11 month. The experiment was set in completely randomized design with three replicates. The results show that, the viability and the infectivity of the fungi in all formulations decreased along the storage. On the 11th month of storage the viability decreased to 65% (peanut oil, the lowest) and 87% (cassava powder, the highest). Similarly, the infectivity of the fungi decreased as well, to 47% (talcum powder, the lowest) and 76 % (molasses and cassava powder, the highest).
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf