Determination of Diazinon residue ih shallot and it's toxicity against armyworm (Spodoptera Exigua)

ABDALLA, Isam Eldeen Ibrahim Hassan, Prof.Dr.Ir. Edhi Martono, M.Sc

2008 | Tesis | S2 Ilmu Hama Tumbuhan

Penelitian dilaksanakan mulai februari sampai Juni 2007 di lab. Pestisida Toksikologi, Fak. Pertanian, UGM. Pnelitian ini bertujuan untuk mengidentifikasi residu diazinon pada bawang merah yang ditanam di daerah Parangtritis, Samas dan Sanden, Kabupaten Bantul, DI. Yogyakarta. Koesioner dibagikan kepada petani untuk mengetahui latar belakang penggunaan diazinon serta aspek lain yang berkaitan, seperti frekuensi dan dosis applikasi. Sampel uji diambil dari ketiga lokasi tersebut dan sampel lain diambil dari Pasar Bantul. Sampel dianalisis dengan metode thin layer chromatography (TLC) dan metode gas chromatography (GC). Residu diazinon terdeteksi dengan metode TLC, dengan nilai Rf sampel yang diperoleh sama dengan nilai Rf pada standar diazinon, yaitu sebesar 0,86 kecuali pada sampel yang berasal lahan petani di daerah Parangtritis tidak menggunakan diazinon. Hasil analisis GC menunjukkan bahwa sampel uji mengandung residu diazinon dalam jumlah kecil, yaitu di bawah batas residu maksimum (MRL), namun residu diazinon tidak terdeteksi pada sampel aat panen yang beasal dari lahan petani di daerah Parangtritis yang tidak menggunakan diazinon. Residu terkecil (2,915 ppb) terdeteksi pada sampel dari Sanden yang dianalisis satu minggu setalah panen. Residu terbesar (23,116 ppb) terdeteksi pada sampel saat panen yang berasal dari Parangtritis. Percobaan lain dilakukan untuk menentukan efek toksik diazinon terhadap Spodoptera exigua. Bioassay dilakukan dengan mencelupkan daun bawang merah ke dalam larutan diazinon selama 10 detik, kemudian dikeringkan selama 15 menit sebelum digunakan. Berdasarkan uji pendahulan, lima konsentrasi diazinon (600, 900, 1200, 1500, 1800 ppm) dan kontrol diaplikasikan pada larva instar ketiga (umur 5-7 hari) dari generasi ketiga yang dipelihara dalam lab. Mortalitas larva diamati 48 jam setalah perlakuan. Data dianalisis menggunakan analisis probit untuk menuntukan nilai LC50. Nilai LC50 yang diperoleh yaitu sebesar 1155,47 ppm, tidak melampaui konsntrasi diazinon yang direkomendasikan (1200 ppm). Populasi yang diuji dikategorikan rentan setelah mendapat paparan diazinon selama 48 jam.

Research was conducted from February until June 2007 in the laboratory of Pesticide Toxicology, Faculty of Agriculture, Gadjah Mada University. It was carried out to identify the residue of diazinon in shallot crop which was grown in Yogyakarta Special Terrytory, Bantul Regency (Parangtritis, Samas and Sanden). Questioners were carried out to find the background of diazinon application and there were many aspects (e.g. frequency, dosage time of application) that could not been thoroughly explained. The samples were taken from these locations and another sample was taken from Bantul market and was analyzed by Thin Layer Chromatography (TLC) and Gas Chromatography (GC). Diazinon residue was detected by TLC, where Rf values of samples were same to Rf diazinon standard (0, 86), except sample which was taken from Parangtritis from farmers plot which not use diazinon. GC results showed that all the samples contained small amount of diazinon residue below maximum residue limit (MRL), whereas residue was not detected in the harvested sample where farmers not apply diazinon in Parangtritis. The least residue level (2,915ppb) was detected in the sample that had been analysed one week after harvesting from Sanden. The highest residue level (23,116 ppb) was detected in the Sample from Parangtritis at harvesting time. Confirmatory experiments were done to determine the toxicity effect of diazinon against Spdoptera exigua, where bioassays were carried out by dipping the shallot leaves in insecticidal solutions for 10 seconds and dried for 15 minutes before use. Based on the preliminary test, five concentrations (600, 900, 1200, 1500, 1800 ppm) and control were used on third instar larvae (5-7 days old) of the third generation which were reared in the laboratory. Larval mortality was reported 48 hrs exposure. Data was analyzed of using probit analysis to determine LC50 values. The results showed that the LC50 of diazinon 48 hrs after exposure was 1155, 47 ppm and not above the recommended concentration (1200 ppm). The population was considered to be susceptible 48 hrs after exposure.

Kata Kunci : Residu Diazinon,Toksisitas,Spodoptera Exigua, residue, diazinon, MRL, toxicity, Spodoptera exigua, shallot