Residue Trial of Dimethoate in Tangerine to Establish Maximum Residue Limit, MRL

Abstract

The trials of dimethoate in concentration of 40% active ingredient were applied on the tangerine experimental plot at Chantaburi and Phatum Thani which are field type and ridge type plantation respectively. The rates of application were 136 and 272 g/rai. the dimethoate was firstly sprayed when the fruits with 1 - 2 cm diameter. At flushing stage, it was sprayed weekly until the fruits were mature. then they were collected and analysed the dimethoate residues in whole fruit in an interval time of 0, 1, 3, 5, 7 and 10 days from the last time of dimethoate application. significantly different of their residue concentrations in 2 plantations especially double dose appeared only the initial degradation range and degradation rate of ridge type higher than the field type due to the external factors such as temperature, light, rainfall intensity and spraying technique.