Division of Entomology, IARI, New Delhi-110 012
*Present Address. I. I. H. R, 155, Upper Palace Orchards, Bangalore -560080.
Studies on the residues of phorate in okra and cauliflower c ops were undertaken at 1ARI, New Delhi. Phorate was applied at 1.5 and 2 0 kg a.i/ha. at the time of sowing/transplanting of the crop and the residues were estimated by bioassay as well as by chemical assay in leaves and fruits/cuds periodically.
The residues of phorate reached below detectable limit in the leaves of okra in about 100 days and in fruits about 75 days after the treatment, The first samples of fruits which were taken after 50 days of treatment were found to contain 1.38 and 1.52 ppm for the first and second dosages respectively showing residues above tolerance limit. The waiting period of nearly 60 days was sufficient to bring down the level of residues below the tolerance limit of 0.1 ppm for okra fruits irrespective of the concentrations.
The residues of phorate in leaves and cauliflower curds were below the tolerance limits in about 82 and 71 days respectively. The first sample of eurds after 50 days of application found to contain 0.78 and 1.06 ppm for the lower and higher dosages respectively. However the residues were below detectable limits on the 75 h day samples.
