The Residue and fate of DDT in paddy rice of subtropical environment were studied byradionuclear tracing. The results obtained were as follows:Loss rate of DDT was rapidly underthe subtropical agroecosystem in Guangzhou

Using normal spray dosage in agroecosystem

DDTresidue in spikes of paddy rice is not over the trace standard( 7 mg/kg)

The DDT residue was2. 1 mg/kg in rice bran

1.8 mg/kg in grain residue was 5. 8 mg/kg in rice bran

4.5 mg/kg ingrain of rice when applicated three times at tillering stage

booting stage and filling stage

It main-lv exists in stems and leaves.Therefore

using normal spray dosage 1000 mg/kg DDT of 15 daysbefore harvesting stage in subtropical crops is safe.