Bioassay of Bacillus sphaericus 2362 against Anopheles barbirostris larvae in Wulanggitang Subdistrict, East Flores Regency

English. A study using biological agent Bacillus sphaericus 2362 (Spherimos FC) was conducted in the Vector Control Research Station Laboratory in Salatiga. It was also applied to ponds belonging to inhabitants of the Sukutukan village, Wulanggitang Sub District, East Flores Regency. These ponds were breeding sites for An. barbirostris larvae. The aim of this study was to determine the efficacy of liquid formulation of B. sphaericus 2362 against An. barbirostris larvae in the laboratory as well as in the field. The effect of B. sphaericus 2362 toward An. barbirostris larvae in the laboratory was conducted according to WHO guidelines to assess the lethal concentrations (LC50 and LC90), calculated through the probit analysis. Laboratory tests showed that after 24 hours of exposure, the LC50 and LC90 values calculated for early fourth-instar larvae of An. barbirostris were 1.2632 ppm and 2.0881 ppm respectively, while after 48 hours of exposure, the LC50 and LC90 were estimated as 0.8637 ppm and 1.5204 ppm respectively. In the field test, the efficacy of Spherimos FC (dosage of 30 ppm) on An. barbirostris larvae was maintained for 35 days with reduction of larval population density of more than 50 percent

Indonesian. Penelitian menggunakan jasad hayati B. sphaericus 2362 telah dilakukan di laboratorium Stasiun Penelitian Vektor Penyakit, Salatiga dan beberapa kolam tidak terawat milik penduduk desa Sukutukan, Kecamatan Wulanggitang, Kabupaten Flores Timur. Kolam tidak terawat tersebut merupakan tempat perindukan jentik An. barbirostris. Penelitian ini bertujuan untuk mengetahui efikasi informasi formulasi liquid B. sphaericus 2362 terhadap jentik An. barbirostris baik di laboratorum maupun di lapangan. Pengujian B. sphaericus 2362 terhadap An. barbirostris di laboratorium dilakukan menurut prosedur WHO dan dimaksudkan untuk mendapatkan nilai LC50 dan LC90 yang dihitung dengan analisis probit. Hasil pengujian selama 24 jam menunjukkan bahwa nilai LC50 sebesar 1,2632 ppm dan LC90 sebesar 2,0881 ppm, sedangkan pengujian selama 48 jam menunjukkan LC50 sebesar 0,8637 ppm dan LC90 sebesar 1,5204 ppm. Dari hasil pengujian di lapangan dengan dosis aplikasi sebesar 30 ppm, efikasi B. sphaericus 2362 terhadap jentik An. barbirostris dapat dipertahankan sampai hari ke 35 dengan persentase reduksi lebih dari 50 persen