Determination of insecticide residues in okra fruit wash using mosquito larvae (Anopheles arabiensis patton) as bio-indicator

A study was conducted to determine insecticide residues in okra (Abelmoschus esculentus L) fruits by using mosquito (Anopheles arabiensis Patton) larvae 3^rd or early 4^th instar as a bio-indicator a tool instead of high technology and costly analytical equipment. Mortality was evaluated by taking 10 larvae/replicate (3 replicates/concentration) and each experiment was repeated thrice to obtain the Probit model used later in the feld study to calculate the residues. The insecticide residues in tape water fruit wash of okra fruits collected from the feld were investigated by using the mosquito larvae from day 1 to day 10 after insecticide application. The results were subjected to the equation of the regression line for each insecticide used, as the Probit model, to calculate the concentration of these insecticides in okra fruits collected from the sprayed feld. The residues were measured from 250 g and 1 kg of fruits as mg/g okra fruit. Malathion and cypermethrin residues in the 0.25 kg batches and 1 kg batches were found below the Acceptable Daily Intake (ADI) of 0.02mg/kg body weight and 0.05mg/kg body weight, respectively, while imidacloprid was above the ADI (0.06mg/kg body weight) in day 1 - day 6, but was equal to ADI in day 2 for the 0.25 kg batches, and below the ADI for the rest of the days. Regarding the 1 kg batches, the imidacloprid was found above the ADI in days 1, 2, 3, and 4, equal to the ADI in days 5 and 6, and below ADI in 7, 8, 9, and 10 days.