The successful control of basal rot disease (BSR) determined by early detection of infection because when the symptoms already appear, generally plants are difficult to save. The earlier the Ganoderma infection is known, the easier the control will be and the losses can be minimized. Therefore, early detection of Ganoderma infection is very necessary, which in this study was carried out by detecting volatile compounds using electronic nose (E-nose). E-nose detection has been carried out to analyze the compounds formed in pure Ganoderma culture. Detection of plants in the field carried out at 4 levels of infection, i.e. healthy, early, moderate and severe infection. The results concluded that Ganoderma mycelium when compared with other fungi (Trichoderma, Aspergillus and Omphalina) showed significant differences when analyzed using an unsupervised PCA chemometric system. The E-nose data processed using machine learning Support Vector Machine (SVM) was able to distinguish the aroma between Ganoderma boninense CSB, G. boninense ‘Rejosari’, and G. lucidum with an accuracy rate of 99.64%. E nose was able to differentiate with high accuracy (90.95%) of each infection level even though there was still a slice between in root sample.

Aktivitas antibakteri ekstrak kulit buah kakao (Theobroma cacao L.) terhadap Escherichia coli, Bacillus subtilis, dan Staphylococcus aureus Antibacterial activity of cocoa pod husk extract (Theobroma cacao L.) against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus

Corn, an important crop in Indonesia still has a low productivity, thus many efforts are required to fulfill its national demand. One of the solutions to improve corn yield is by applying biostimulant containing chitosan as an active ingredient. Chitosan has been proved to increase plant growth and resistance against diseases. The objective of this research was to study the effects of several chitosan formulas on the yield and diseases occurance in sweet corn (Zea mays var. Bonanza). The chitosan formulas tested were soluble liquid(SL), wettable powder (WP), nano chitosan (NN), and unformulated chitosan (CH). The experiment was arranged using a randomized block design with three replications. All chitosan formulas were applied by seeds soaking for 20 minutes, followed by foliar spraying on corn plants at three weeks after planting (WAP), with the concentration of 500 ppm (400 L/ha spray volume), every threeweeks until 9 WAP. Parameters observed were brix value, weight of corn cobs, weight of corn biomass, and plant diseases including downy leaves, leafblight and leaf rust. The results showed that NN formula increased the brix value up to 7%, the corn cob weight up to 49% and the biomass weight upto 34% compared to the control; whereas SL formula reduced the incidence of downy mildew by 53% at 3 WAP and leaf blight disease by 51% at 6 WAP. In addition, the incidence of corn leaf rust reduced 59-71% in corn plant subjected to all chitosan formulas. Based on the results, application of chitosan in NN formula was best in increasing yield, while in SL formula was best in reducing the incidence of important corn diseases.[Keywords: downy mildew, chitosan formula, seed treatment]AbstrakJagung sebagai salah satu komoditas pangan penting di Indonesia masih memiliki produktivitas yang rendah sehingga diperlukan usaha untuk memenuhi kebutuhan jagung nasional. Salah satu cara untuk meningkatkan hasil jagung adalah dengan aplikasi biostimulan yang mengandung bahan aktif kitosan. Kitosan telah terbukti mampu meningkatkan pertumbuhan dan daya tahantanaman terhadap penyakit. Penelitian ini bertujuan mempelajari pengaruh beberapa formula kitosan terhadap hasil dan kejadian penyakit pada tanaman jagung manis (Zea mays var. Bonanza). Formula kitosan yang diuji adalah cairan yang dapat larut (soluble liquid, SL), tepung yang dapat dibasahi (wettable powder, WP), nano kitosan (nano chitosan, NN), dan kitosan non formulasi (unformulated chitosan, CH). Percobaan dilakukan menggunakan rancangan acak kelompok (RAK) dengan tiga ulangan. Masingmasing formula kitosan tersebut diaplikasikan melalui perendaman benih selama 20 menit yangdiikuti dengan penyemprotan daun pada tanaman jagung berumur tiga minggu dengan konsentrasi 500 ppm (volume semprot 400 L/ha) yang dilakukan setiap tiga minggu sampai tanaman berumur sembilan minggu. Parameter yangdiamati adalah nilai brix, bobot tongkol jagung, bobot biomassa jagung, dan penekanan kejadian beberapa penyakit tanaman meliputi bulai, hawardaun, dan karat daun. Hasil penelitian menunjukkan bahwa aplikasi kitosan NNmeningkatkan nilai brix jagung manis hingga 7%, bobot tongkol jagung hingga 49% dan bobot biomassa hingga 34% dibandingkan dengan kontrol. Sementara itu, aplikasi kitosan SL dapat menekan kejadian penyakit bulai hingga 53% padaumur tanaman 3 minggu setelah tanam (MST) dan penyakit hawar daun hingga 51% pada umur 6 MST. Selain itu, kejadian penyakit karat daun jagung juga dapat ditekan 59-71% pada aplikasi keempat formula kitosan. Berdasarkan hasiltersebut, aplikasi kitosan NN paling optimal dalam meningkatkan hasil panen jagung manis, sedangkan aplikasi kitosan SL paling optimal dalam menekan kejadian beberapa penyakit pada tanaman jagung.[Kata Kunci: bulai, formula kitosan, perlakuan benih]

No abstract

Plastic wastes  have  become a serious problem  of  the world  because of  unbiodegradable  property. There are many  solutions to this problem  and  one of  them is by replacing conventional plastic base  material with  the  biodegradable  materials. Bioplastic material that is quite important for industries and  recently being developed  by  scientists  is Polyhydroxyalcanoate (PHA). It is a natural polyester which  can be produced  by several microorganisms, like bacteria and algae. Bacterial isolations  from landfills waste and  palm oil mill effluents were conducted on this research. Preliminary screenings of PHA-producing-bacteria were examined qualitatively using  0.05%  Nile red dye. The selection results showed  that among 32 bacterial isolates, 10  of  them could  accumulate PHA  which  could be detected qualitatively through  its  fluorescence in  UV  ray  at λ 235 nm. TH-D092 and LC-S05 isolates originated  respectively  from landfill and  palm oil mill effluent had ability to accumulate PHA respectively  6.67 and 9.44% dried cell weight. Identification  of  the microbe concluded  that TH-D092  was Pseudomonas aeroginosa, whilst LC-S05 and LC-D02 isolates was  Bacillus subtilis.AbstrakLimbah plastik menjadi masalah serius yang dihadapi dunia karena sulit didegradasi mikroba. Salah satu solusi masalah adalah dengan mengganti bahan dasar plastik konvensional dengan plastik biodegradable (bioplastik). Bahan bioplastik yang cukup penting bagi indutri  dan saat ini terus dikembangkan oleh peneliti adalah Polihidroksial- kanoat (PHA). PHA merupakan poliester alami yang dapat diproduksi oleh mikroorganisme, seperti bakteri dan alga. Pada penelitian dilakukan isolasi bakteri dari tanah tempat pembuangan sampah (TPS) dan limbah cair pabrik kelapa sawit (LCPKS). Penapisan awal bakteri penghasil PHA dilakukan secara kualitatif menggunakan pewarna Nile red  0.05%. Hasil penapisan menunjukkan diantara ke-32  isolat bakteri diperoleh 10 isolat mampu mengakumulasi PHA secara kualitatif, yaitu isolat yang mampu menimbulkan  pendaran floresen pada sinar UV  pada λ 235 nm. Isolat TH-D092 dari tanah tempat pembuangan  sampah dan isolat LC-S05 dari limbah cair pabrik kelapa sawit memiliki kemampuan mengakumulasi PHA berturut-turut  6,67 dan 9,44% dari berat sel kering. Hasil identifikasi spesies bakteri menunjukkan bahwa isolat TH-DO9 termasuk Pseudomonas aeroginosa, LC-SO5 dan LC-DO2 termasuk Bacillus subtilis.