PENGENDALIAN NYAMUK Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) MENGGUNAKAN BEBERAPA ISOLAT BAKTERI Lysinibacillus sphaericus ENDOGENIK INDONESIA

IKA INDAYATI, Drs. Hari Purwanto, M. P., Ph. D

2021 | Tesis | MAGISTER BIOLOGI

Penelitian ini bertujuan untuk mengidentifikasi isolat bakteri yang telah dikoleksi berdasarkan gen 16S rRNA, melakukan uji optimasi media bulu ayam untuk perbanyakan isolat L. sphaericus dan melakukan uji patogenesitas isolat bakteri yang telah dikoleksi terhadap larva Cx. quinquefasciatus. Isolat bakteri yang digunakan dalam penelitian ini dikoleksi dari tanah perakaran, kotoran burung dan guano. Berdasarkan hasil analisis sekuen 16S RNA isolat 229C, 6B4, 6.2 dan 4D21 diperoleh hasil bahwa keempat isolat tersebut termasuk dalam spesies L. sphaericus dengan similarity scores berkisar antara 97% sampai 100%, media kaldu bulu ayam dengan berat kering 100g/L air ditambah garam yang terdiri dari 1 mg/L CaCO3; 1 mg/L MgSO4; 0,1 mg/L FeSO4; 0,1 mg/L MnSO4, dan 0,1 mg/L ZnSO4 adalah media yang paling baik digunakan karena isolat hasil perbanyakan menggunakan media tersebut menunjukkan tingkat patogenesitas paling tinggi. Hasil uji patogenesitas 6 isolat 15.4, 229C, 1593, 6B4, 6.2 dan 4D21 menunjukkan bahwa isolat 15.4 memiliki tingkat mortalitas larva paling tinggi sehingga berpotensi untuk digunakan sebagai agensia hayati untuk mengendalikan nyamuk vektor penyakit.

This study aims to identify bacterial isolates collected based on the 16S rRNA gene, to perform optimization test of chicken feather media for the propagation of L. sphaericus isolates, and to carry out the pathogenicity test of the bacterial isolates collected on Cx. quinquefasciatus larvae. Bacterial isolates used in this study were collected from root soil, bird droppings and guano. The identification of the type of bacteria was carried out based on the 16S rRNA gene fragment. Based on the results of the 16S RNA sequence analysis of isolates 229C, 6B4, 6.2 and 4D21, it was found that the four isolates were included in the L. sphaericus species with similarity scores ranging from 97% to 100%. The media optimization for the propagation of L. sphaericus isolates was carried out using chicken feather broth. The pathogenicity of bacteria was measured based on the mortality of Cx. quinquefasciatus larvae to know whether it has pathogenicity equal to or higher than strain 1593. The results showed that the broth of chicken feathers with a dry weight of 100g/L water, added with salt consisting of 1 mg/L CaCO3; 1 mg/L MgSO4; 0.1 mg/L FeSO4; 0.1 mg/L MnSO4, and 0.1 mg/L ZnSO4, is the best media to use because the isolates propagated using this media showed the highest level of pathogenicity. The pathogenicity test results of 6 isolates 15.4, 229C, 1593, 6B4, 6.2 and 4D21 showed that isolate 15.4 has the highest larval mortality rate, so it is potentially used as a biological agent to control disease vector mosquitoes.

Kata Kunci : Lysinibacillus sphaericus, Culex quinquefasciatus, uji patogenisitas, Indonesia, bulu ayam.