Judul: Aktivitas Insektisida Ekstrak Buah Cabai Jawa (Piper relrojrac/lIl71, Piperaceae) terhadap He/ope/tis antonii Sign. (Hemiptera: Miridae)
Abstrak: Helopeltis antonii Sign. (Hemiptera: Miridae) is an important pest of cocoa, tea, and cashew nuts. This insect pest sucks shoot and nut saps of plants causing blackish brown spots. Application of synthetic insecticides is commonly used to control Helopeltis spp. due to insecticide fast action. However, use of synthetic chemical insecticides can cause pest resistance and resurgence and outbreak of secondary pests, killing of non-target organisms as well as environmental contamination. Therefore, it is necessary to search for environmental friendly strategy to control H. antonii. The objectives of this study were to test the toxicity of Piper retrofractum extract to H. antonii adults, evaluate the effect of sublethal concentrations of the extract on the number of progeny nymphs of H. antonii, and to evaluate the persistence of the extract against mortality and oviposition of H. antonii. Cucumber was used as an alternate host for mass rearing and testing medium. The study was conducted in several stages: insect rearing, extraction, toxicity test, effects of sublethal, and persistency test. Toxicity test of P. retrofractum extract was conducted at concentrations of 0.05%, 0.10%, 0.15%, 0.20%, 0.25% and 0.3% based on the result of preliminary test. The extract was diluted in a mixture of acetone, methanol, and Tween 80 (5:5:5 v/v) [final concentration of 1.2%] and then diluted with distilled water until the desired volume. In addition, control solution was also prepared containing distilled water and a mixture of acetone, methanol, and Tween 80 (5:5:2 v/v) 1.2%. For each treatment, 10 individuals of H. antonii adults were used with five replications. The effect of sublethal test was conducted at concentrations equivalent to LC25 and LC50. The extract was sprayed on the whole surface of cucumber. Then the treated cucumbers and fourth instar nymphs were put in a plastic container (13 cm and diameter 14 cm) and the insects were held for 48 hours. After 48 hours, the treated cucumbers were replaced with untreated cucumbers until the nymphs became adults. The adult insects were then paired to obtain 10 pairs for each concentration level and control. Each pair of adult insects was placed into plastic containers and fed with untreated cucumbers. All of the adult insects were maintained until they died. Observations were made by counting the number of progeny nymphs in each treatment. Persistence test of P. retrofractum extract was conducted at concentrations of 0.49% (LC95), 0.98% (2 x LC95) and control ([aceton + methanol + Tween 80,5:5:2] + distilled water). The test extract emulsions were put into a clear glass spray bottle then exposed under sunlight for 7 hours/day from 08:00 to 15:00 pm for 0, 1, 3, and 5 days. These extracts were subsequently used for testing of the effect on mortality and oviposition of H. antonii. In the mortality test, P. retrofractum extracts that had been exposed under sunlight for 0, 1, 3, and 5 days were sprayed on H. antonii using a hand sprayer. Ten H. antonii adults were used v for each treatment and each treatment was replicated five times. The percentage of mortality was counted at 1, 2, 3, 4,
Keyword: Botanical insecticide, mortality, oviposition, persistence

Judul: The Development of Nanoemulsion Formulation of Botanical Insecticides Containing Piper retrofractum Vahl. and Curcuma xanthorrhiza Roxb. Extract Mixtures for Helopeltis antonii Sign. Control (Hemiptera: Miridae) on the Cocoa Plant.
Abstrak: Serangan Helopeltis antonii Sign. (Hemiptera: Miridae) menjadi kendala pengembangan kakao karena produksi buah dapat turun hingga 60%. Salah satu alternatif pengendaliannya menggunakan insektisida nabati, misalnya ekstrak tanaman dari famili Piperaceae, Asteraceae, dan Zingiberaceae. Beberapa senyawa aktif insektisida nabati bersifat tidak larut air, bahkan ada yang hanya larut dalam minyak dan tidak larut dalam air maupun minyak sehingga diperlukan senyawa kimia lain maupun perlakuan tertentu agar dapat larut. Disamping itu, pengembangan insektisida nabati terkendala adanya penurunan aktivitas biologis karena adanya reaksi oksidatif maupun polimerisasi. Salah satu cara untuk mengatasi kelemahan tersebut adalah dengan melakukan formulasi insektisida nabati dengan nanoteknologi. Nanoemulsifikasi sederhana dapat dilakukan dengan homogenisasi energi rendah mekanisme difusi spontan. Pengembangan formulasi insektisida nabati juga perlu disertai dengan informasi fitotoksisitas, persistensi, dan keamanannya terhadap organisme nontarget, sebagai syarat yang harus dipenuhi untuk pendaftaran insektisida sebelum dipasarkan. Penelitian ini bertujuan (1) mengevaluasi toksisitas dan aktivitas penghambatan makan ekstrak etil asetat buah Piper retrofractum (EaPr) dan Piper aduncum (EaPa) (Piperaceae); ekstrak etanol bunga Tagetes erecta (EtTe) dan ekstrak metanol Tithonia diversifolia (MeTd) (Asteraceae); serta ekstrak etanol rimpang Curcuma xanthorrhiza (EtCx) dan Alpinia galanga (EtAg) terhadap nimfa instar ketiga dan imago H. antonii, serta aktivitas penghambatan peneluran terhadap imago; (2) mendapatkan perbandingan campuran ekstrak yang kompatibel antara ekstrak EaPr dengan EtCx (hasil terbaik penelitian sebelumnya) dan mengevaluasi toksisitasnya terhadap nimfa instar ketiga H. antonii; (3) mendapatkan formulasi dan karakter fisikokimia nanoemulsi campuran ekstrak EaPr dan EtCx serta mengevaluasi toksisitasnya terhadap nimfa instar ketiga H. antonii; (4) mengevaluasi fitotoksisitas formulasi tunggal dan campuran nano dan nonnano ekstrak EaPr dan EtCx terhadap bibit kakao, persistensinya terhadap nimfa instar ketiga H. antonii, dan keamanan hayati terhadap serangga predator Sycanus annulicornis, serta keefektifan di tingkat semilapangan. Penelitian meliputi empat kegiatan. Kegiatan pertama (1) adalah bioaktivitas insektisida nabati dari ekstrak tanaman Piperaceae, Asteraceae, dan Zingiberaceae terpilih terhadap H. antonii. Bahan tanaman yang digunakan adalah buah P. retrofractum dan P. aduncum (Piperaceae); bunga T. erecta dan T. diversivolia (Asteraceae); dan rimpang C. xanthorrhiza dan A. galanga (Zingiberaceae). Pengujian aktivitas hayati, meliputi uji toksisitas, penghambatan makan dan peneluran. Uji toksisitas menggunakan residu pada pakan dan semprot serangga. Uji penghambatan makan dan peneluran menggunakan metode residu pada pakan. Formulasi yang menunjukkan lethal concentration (LC) terendah dan mampu menghambat makan dan peneluran dipilih untuk diformulasi campuran. Kegiatan kedua (2) adalah kompatibilitas campuran ekstrak EaPr dan EtCx untuk pengendalian H. antonii. Ekstrak EaPr dan EtCx merupakan ekstrak terbaik kegiatan I. Perbandingan ekstrak EaPr dan EtCx pada uji kompatibilitas, yaitu 4:1, 2:1, 1:1, 1:2, dan 1:4 (w/w). Pengujian menggunakan metode semprot serangga. Sifat interaksi campuran ditentukan dari nilai Indeks Kombinasi. Kegiatan ketiga (3) adalah karakteristik dan toksisitas formulasi nanoemulsi campuran ekstrak EaPr dan EtCx terhadap H. antonii. Perbandingan campuran ekstrak terbaik pada kegiatan kedua, yaitu EaPr:EtCx = 2:1 dan 1:2 (w/w), diformulasi nanoemulsi dengan teknik emulsifikasi energi rendah mekanisme spontan. Pengujian toksisitas nanoemulsi dilakukan dengan metode semprot serangga. Kegiatan keempat (4) adalah keamanan hayati dan keefektifan formulasi nanoemulsi campuran EaPr dan EtCx terhadap H. antonii. Formulasi yang diujikan, meliputi ekstrak tunggal EaPr dan EtCx; campuran nano dan nonnano EaPr dan EtCx (1:2 dan 2:1; w/w); serta pembanding
Keyword: keamanan hayati, nanoemulsi, nanoteknologi, persistensi, sinergistik, keamanan hayati, nanoemulsi, nanoteknologi, persistensi, sinergistik

Judul: Query Expansion based on Bilingual Dictionary Using Conditional Probability
Abstrak: Query expansion is a technique that can be used to bridge vocabulary gaps between queries and documents in the collection. With query expansion, user will be helped to formulate queries well so that user will optimize the search result. In this study, the expansion term was resulted from the translation of bilingual dictionary. Subsequently, several terms of expansion were elected based on the closeness of its relationship with the original query. This research showed that conditional probability can be used to select expansion term in bilingual translation method query expansion. The result of 1000 documents was more than 97% relevan document can be retrieved by this system. The more expansion term used, the larger number relevan document was retrieved.
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