Abstract
The behavior of diazinon in the paddy field was studied chemically and biologically after the water surface application, which was used practically. On the first day after the application of diazinon 3% granules (3kg per 10a), 66g of diazinon was detected in water, 38g in soil, 0.6g in rice plant and 3.6g of gaseous diazinon in air in 24hr. On the second day 75g of diazinon in all were found, on the fourth day 21g, and on the 15th day only 2g of diazinon. Concentration of the chemical in rice plant depended on diazinon concentration in water. It seemed that 0.3ppm of diazinon in rice plant was enough to kill the larvae of the rice stem borer for successive 9 days, that is, effective against the larvae which infested the rice plant between 4 days before and 4 days after application.
