Judul: Evaluasi Potensi Asap Cair dalam Melindungi Biji Kakao Terhadap Hama Gudang (Corcyra cephalonica)
Abstrak: Cocoa is a very important crop all over the world. For the countries that grow it, it has become a major export commodity and foreign exchange earner. To importing countries, it is also considered a valuable raw material for the manufacturing of various products. The postharvest handling of cocoa bean is critical because of its ability to affect the final quality of products. Storage as an aspect of postharvest handling is very critical and must be carried out well to reduce risk factors like insect attacks on beans. Efforts to curb it using synthetic pesticides have ended up with other serious problems such as pesticide residue in food products, depletion of the ozone layer, and development of resistance by target pests. In the meantime, improper disposal of the cocoa pod husk (CPH) waste after pod breaking has also been found to be serving as alternate hosts and hideout for cocoa plant disease pathogens such as Phytophthora spp. The resulting disease causes a reduction in the quantity and quality of beans harvested. The nature of the problem described above inspired the design of this research to investigate the possible use of CPH to produce wood vinegar/ liquid smoke (LS) as a biopesticide for controlling the storage pests of cocoa beans. In this study, the third instar larva of Corcyra cephalonica was used model insect. The specific objectives include ; 1, determining the compounds present in CPH liquid smoke. 2, ascertaining the toxicity, repellence and feeding deterrence effects of the liquid smoke against Corcyra cephalonica, and 3, investigating the effect of CPH liquid smoke treatment on the quality of cocoa beans. The study was set up in a Completely Randomized Design (CRD) with four replications. There were five treatments representing various concentration rates of liquid smoke :10%; 20%; 50%; 100 % concentrations and control (0 %) distilled water. The treatment was applied to the outer surface of mini jute sacks containing cocoa beans. The GCMS analysis of the LS detected 20 compounds. The compounds with higher concentrations were Butanamine (27%), Acetic acid (8.23%), 2-Pyrrolidinone (7.25%), Butanoic acid (6.96%), 2,5-Pyrrolidinedione (6.93%), 2H-Pyran-2-on (6.45%) and Cyclopropyl carbinol (5.62%). Allyl N butanoate and Hydrazine compounds were found to have a strong odour hence possess high potential for use as an insect repellent. In the test for mortality, LS did not cause enough mortality effect against Corcyra cephalonica. At the undiluted concentration of 100%, the LS could kill just half (52.5 %) of the insect population after five days (120hrs) of treatment. However, from the repellency test, 100% concentration of LS repelled as much as 90% of the insect population. The feeding deterrence index (FDI) was also highest at the 100% treatment. This, however, was not significantly different from the performance of the 50% concentration, which also deterred 90% of feeding activity. The FDI effect also caused a reduction in bean damage: 7.65% damage for beans treated with 100% LS as against 22% damage in beans without treatment. Weight loss was also reduced from 2.13% in control to 0.11 % in beans treated with 100% LS. Further quality
Keyword: cocoa beans, Corcyrca, liquid smoke, Pyrolysis, postharvest, Storage Pest

Judul: Pengendalian Penyakit Phytophthora dengan Fungisida Asam Fosfit pada Tanaman Kakao melalui Metode Injeksi Batang, Penyemprotan Kulit Batang, dan Irigasi Tetes
Abstrak: Cocoa production has been declining due to factors such as plant age, poor planting materials, and high pest and disease attacks. Phytophthora palmivora Butl. is a hemibiotrophic phytopathogen that may infect a wide variety of hosts, including many agricultural crops across the globe. Phytophthora palmivora causes two types of disease in cocoa trees: pod rot and stem canker resulted in the reduction of the quality and quantity of cocoa beans, with losses up to 30%. This research was aimed to determine the effective and economically viable disease management through phosphonic application. This study was conducted on a 5-year-old cocoa plantation in South Sulawesi, Indonesia, using a trunk injection method, stem bark spray, and drip irrigation. All treatments resulted in a substantial reduction in lesion size and sporulation on inoculated sample with differing levels of effectiveness. Considering its effectiveness in suppressing Phytophthora disease development, 80 ml and 40 ml-injected tree and 40 ml-sprayed tree of phosphonic acid showed the best results. Although higher doses (80 ml/tree) provide better control of stem canker, the use of the lowest dose (20 ml/tree) was adequate to suppress lesion development, particularly in the injection method. While the economical analysis on 1 ha cocoa field showed that injection of 80 ml/tree and drip irrigation of 40 ml/tree produced the highest income per season of IDR 136 and 132 million., Produksi kakao terus mengalami penurunan signifikan yang diakibatkan oleh beberapa faktor seperti umur tanaman, bahan tanam yang rentan, dan tingginya serangan hama dan penyakit. Phytophthora palmivora Butl. merupakan cendawan hemibiotrofik yang dapat menginfeksi berbagai macam inang yang tersebar di seluruh dunia, termasuk kakao. Phytophthora palmivora menyebabkan dua jenis penyakit pada tanaman kakao yaitu penyakit busuk buah dan kanker batang yang mengakibatkan penurunan kualitas dan kuantitas biji kakao, dengan kerugian mencapai 30%. Penelitian ini bertujuan menentukan pengendalian penyakit yang efektif dan ekonomis melalui aplikasi asam fosfit. Penelitian ini dilakukan pada perkebunan kakao berumur 5 tahun di Sulawesi Selatan, Indonesia, dengan menggunakan metode injeksi batang, penyemprotan kulit batang, dan irigasi tetes. Berdasarkan hasil, aplikasi asam fosfit menunjukkan penurunan substansial dalam diameter lesi dan sporulasi pada sampel yang diinokulasi dengan tingkat efektivitas yang berbeda. Hasil pengamatan menunjukkan bahwa injeksi asam fosfit dengan dosis 80 dan 40 ml/pohon, penyemprotan pada dosis 40 ml/pohon, dan melalui irigasi tetes 40 ml/pohon merupakan hasil terbaik dalam menekan perkembangan penyakit phytophthora. Meskipun demikian, penggunaan dosis terendah (20 ml/pohon) telah mampu menekan perkembangan penyakit kanker batang, terutama pada metode injeksi. Sementara itu, analisis ekonomi pada lahan kakao seluas 1 ha menunjukkan bahwa injeksi 80 ml/pohon dan drip irrigation 40 ml/pohon menghasilkan pendapatan per musim tertinggi yaitu 136 dan 132 juta rupiah.
Keyword: cocoa pod rot, phosphonic acid, Phytophthora palmivora, stem canker

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
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