Judul: In Vitro Antagonistic Assay of Endophytic Fungi Isolated from Pilea microphylla (L.) Liebm against Fusarium oxysporum f. sp. cubense (Foc)
Abstrak: ISHMAH AFIAH. In Vitro Antagonistic Assay of Endophytic Fungi Isolated from Pilea microphylla (L.) Liebm against Fusarium oxysporum f. sp. cubense (Foc). Supervised by SRI LISTIYOWATI and TRIADIATI. Endophytic fungi are reported capable of effectively inhibit the growth of plant pathogenic fungi. Utilization of endophytic fungi as an environmentally friendly biological control agent still needs to be done. This study aimed to test the in vitro antagonism ability of the endophytic fungi from Pilea microphylla (L.) Liebm against the pathogenic fungi Fusarium oxysporum f. sp. cubense (Foc) and analyzed the types of interactions and their inhibitory mechanisms. Antagonism test was performed by pairing the endophytic fungi and Foc using dual culture methods. The control was made without the addition of endophytic fungi as the antagonisms. Analysis of percentage inhibition (DH) and growth rate of radial mycelia Foc was performed using a completely randomized design (CRD). The results showed that the isolate PM 1A2.4 has a moderate inhibitory ability (DH 41.58%), with slight inhibition type of interaction exhibited and probably perform antibiosis mechanism. The isolate PM 2A2.3 has a very weak inhibitory ability (DH 10.76%), indicated by the Foc mycelia grew through (overgrowing) the mycelia of endophytic fungi. Similarly, with the isolate PM 2A2.4 against the Foc (DH 19.68%), the Foc mycelia grew around part of the mycelia of endophytic fungi. The interaction of the two endophytic fungi against Foc was competitive. The Foc hyphae paired with the isolate PM 1A2.4 and PM 2A2.3 showed vacuolization, whereas with the isolate PM 2A2.4 there was no difference with control. The endophytic fungi of P. microphylla had various antagonistic activity against Foc. Keywords: antibiosis, competition, dual culture, inhibition, vacuolization, Cendawan endofit dilaporkan mampu menghambat pertumbuhan cendawan patogen tanaman secara efektif. Pemanfaatan cendawan endofit sebagai agen pengendalian hayati yang ramah lingkungan di bidang pertanian masih perlu dilakukan. Penelitian ini bertujuan menguji kemampuan antagonisme cendawan endofit asal tumbuhan Pilea microphylla (L.) Liebm terhadap cendawan patogen Fusarium oxysporum f. sp. cubense (Foc) secara in vitro dan menganalisis tipe interaksi serta mekanisme penghambatannya. Uji antagonisme dilakukan dengan memasangkan cendawan endofit dan Foc menggunakan metode kultur ganda. Kontrol dibuat tanpa penambahan cendawan endofit sebagai antagonisnya. Analisis persentase daya hambat (DH) dan rata-rata pertumbuhan miselia radial Foc dilakukan menggunakan rancangan acak lengkap (RAL). Hasil penelitian menunjukkan isolat PM 1A2.4 memiliki kemampuan hambat sedang (DH 41,58%), dengan tipe interaksi slight inhibition yang diduga melalui mekanisme antibiosis. Isolat PM 2A2.3 memiliki kemampuan hambat sangat lemah (DH 10,76%), sehingga tampak miselium Foc tumbuh melewati (overgrowing) miselium cendawan endofit. Demikian juga isolat PM 2A2.4 terhadap Foc (DH 19,68%), miselium Foc tumbuh mengelilingi (growth around) sebagian sisi miselium cendawan endofit. Interaksi kedua cendawan endofit tersebut terhadap Foc bersifat kompetisi. Hifa Foc yang dipasangkan dengan isolat PM 1A2.4 dan PM 2A2.3 mengalami vakuolisasi, sedangkan isolat PM 2A2.4 tidak ada perbedaan dengan kontrol. Cendawan endofit asal tumbuhan P. microphylla memiliki kemampuan antagonisme yang bervariasi terhadap Foc. Kata kunci: antibiosis, daya hambat, kompetisi, kultur ganda, vakuolisasi, Endophytic fungi are reported capable of effectively inhibit the growth of plant pathogenic fungi. Utilization of endophytic fungi as an environmentally friendly biological
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Judul: Morphological Characterization and Antagonism Mechanism of Entomopathogenic Fungi towards Fusarium oxysporum f. sp. cubense (Foc) Causal Agents of Banana’s Panama Disease
Abstrak: Fusarium oxysporum f. sp. cubense (Foc) merupakan cendawan patogen tular tanah penyebab layu panama pada tanaman pisang. Pengendalian Foc banyak dilakukan termasuk menggunakan agen hayati seperti cendawan. Namun, potensi cendawan entomopatogen sebagai agen biokontrol patogen Foc belum banyak diteliti. Oleh sebab itu, penelitian ini bertujuan mengevaluasi mekanisme antagonisme empat kultur cendawan entomopatogen PS 4, PS 9, PS 11, yang berasal dari kawasan Situ Gunung, Sukabumi, Jawa Barat, serta KRC asal Kebun Raya Cibodas terhadap Foc, dan mengarakterisasi morfologinya. Cendawan entomopatogen diamati ciri morfologinya dan dipasangkan dengan Foc menggunakan metode kultur ganda. Kontrol dibuat tanpa berpasangan dengan cendawan entomopatogen. Persentase daya hambat dan pertumbuhan diameter koloni Foc pada uji antagonisme disusun dalam Rancangan Acak Lengkap (RAL) kemudian dianalisis menggunakan program SPSS versi 25.0. Cendawan entomopatogen yang digunakan dalam penelitian ini memiliki hifa septat dan tidak bersporulasi serta pertumbuhan koloninya lebih kecil dari Foc. Kultur KRC menghambat koloni Foc sebesar 67,18% dan termasuk aktivitas antagonisme kuat. Kultur PS 4, PS 9, dan PS 11 menghambat koloni Foc berturut-turut sebesar 18,37%, 31,86%, dan 21,72% serta termasuk aktivitas antagonisme lemah. Kultur PS 9 menyebabkan pembentukan klamidospora pada hifa Foc, sedangkan ketiga kultur lainnya menyebabkan pembentukan vakuolisasi pada hifa Foc. Semua cendawan entomopatogen menghambat melalui mekanisme kompetisi ruang., Fusarium oxysporum f. sp. cubense (Foc) is a soil-borne pathogenic fungus that causes Panama wilt on banana plants. Foc control has been done, including using biological agents such as fungi. However, the potential of entomopathogenic fungi as biocontrol agents for Foc pathogen has not been widely studied. Therefore, this study aimed to evaluate the mechanism of antagonism of four entomopathogenic fungi PS 4, PS 9, and PS 11 originating from Situ Gunung, Sukabumi, West Java, and KRC from Cibodas Botanical Gardens against Foc, and to characterize their morphology. The entomopathogenic fungi were observed for their morphological characteristics and paired with the pathogenic fungi Foc using the dual culture method. The control was made without the addition of entomopathogenic fungi. The percentage of inhibition and growth of Foc colony diameter in the antagonism test was arranged in a Completely Randomized Design (CRD) and then analyzed using the SPSS version 25.0 program. The entomopathogenic fungi used in this study had septate and non-sporulated hyphae and smaller colony growth than Foc. KRC culture inhibited Foc colonies by 67.18% and included vigorous antagonism activity. PS 4, PS 9, and PS 11 cultures inhibited Foc colonies by 18.37%, 31.86%, and 21.72%, respectively, and included weak antagonistic activity. The PS 9 culture caused the formation of chlamydospores in the Foc hyphae, while the other three cultures caused the formation of vacuolization in the Foc hyphae. All entomopathogenic fungi inhibit through the mechanism of space competition.
Keyword: chlamydospores, dual cultures, inhibition, pathogen, vacuolization

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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