Effect of gamma irradiation [60 Co] against Bactrocera carambolae Drew & Hancock in vitro and in vivo. Bactrocera carambolae Drew & Hancock is one of the most important pests on guava fruit. According to a quarantine regulation in export-import commodities, irradiation treatment is a suitable methods for eradicating infested organism, which is relatively safe for the environment. The aim of this research was to determine mortality doses and an effective dose of [ 60 Co] gamma ray irradiation for the eradication purpose, and its implication on the survival of fruit fly B. carambolae. Two irradiation methods of in vitro dan in vivo were carried out, by exposing egg and 3 rd instar larvae of B. carambolae obtained from the laboratory reared insect. Eleven doses of gamma ray irradiation of 0, 30, 50, 75, 100, 125, 150, 175, 200, 300, 450, and 600 Gy were applied, respectively. The level of 99% fruit fly mortality was estimated by the value of LD 99 using probit analysis and the number of larvae, pupae and adult survival were evaluated by analysis of variance (ANOVA), and the means compared by Tukey's test, at 5% of significance level. These result showed that the effective lethal dose (LD 99 ) of irradiation that could be successful to eradicate eggs and 3 rd instar larvae in vitro were 2225 and 2343 Gy and in vivo were 3165 dan 3177 Gy, respectively. Almost all of the treated larvae survived and developed to pupae, therefore only the minimum irradiation dose of 30 Gy allowed the pupae to develop into adults.
Key words: Bactrocera carambolae, eradication, irradiation, LD 99
ABSTRAK
Pengaruh iradiasi sinar gamma [60 Co] terhadap Bactrocera carambolae Drew & Hancock in vitro dan in vivo. Bactrocera carambolae Drew & Hancock merupakan organisme pengganggu tumbuhan (OPT) penting pada buah jambu biji. Sehubungan dengan regulasi karantina dalam lalulintas komoditas ekspor, iradiasi merupakan upaya membebaskan OPT dari komoditas tersebut yang relatif aman terhadap lingkungan. Penelitian ini bertujuan menentukan dosis lethal dan dosis efektif iradiasi sinar gamma [ 60 Co] untuk mengeradikasi lalat buah B. carambolae, serta mengamati implikasi terhadap keloloshidupannya. Dua metode pengujian in vitro dan in vivo masing-masing diaplikasikan terhadap telur dan larva instar 3 B. carambolae hasil perbanyakan laboratorium. Sebelas dosis perlakuan iradiasi diaplikasikan berturut-turut: 0, 30, 50, 75, 100, 125, 150, 175, 200, 300, 450, dan 600 Gy. Tingkat mortalitas 99% (LD 99 ) ditentukan melalui program probit, dan kemampuan keloloshidupan larva, pupa, dan imago dibedakan melalui uji Tukey pada taraf 5%. Hasil perlakuan menunjukkan bahwa dosis lethal iradiasi efektif (LD 99 ) berhasil mengeradikasi telur dan larva instar 3 berturut-turut sebesar 2225 dan 2343 Gy in vitro, serta 3165 dan 3177 Gy in vivo. Hampir seluruh larva perlakuan yang lolos hidup berhasil berkembang menjadi pupa, namun hanya dosis iradiasi terendah, yaitu 30 Gy saja yang dapat berkembang menjadi imago.
