Presented in All India Weed Science Symposium from Jan. 29–31 held at MAU, Parbhan.
The experiment was conducted at the irrigation canal running across the Research Farm of Haryana Agricultural University, Hissar for testing the various herbicide mixtures and their frequency of application during 1975–76 and 1976–77. During both the years herbicides were sprayed either once or in 2–3 repeated doses at an interval of 10 days starting from 10th August, when there is sufficient rainfall to fix the herbicides in soil. It was obs;r-ved that single application of dalapon (2,2-dichloropropionic acid) when applied alone or in mixture with 2,4-D (2,4-dichlorophenoxy acetic acid) did not enhance killing weeds beyond 30 per cent. However, the mortality ‘percentage increased with corresponding increase in repeated application of herbicide. Diuron (3 (3,4-dichlorophenyl) -1, 1-dimethylurea) + MSMA (monosodium methanearsonate) at 10 4–5 kg a.i./ha proved most potent in killing the canal barik weeds at all the frequency levels. In the second year 2 or 3 application of dicryl (3, 4-dichloro-2-methyl acrylanilide) -I- atrazine (2-chloro-4-(ethyl amino)-6-(isopropy-lamino) -5-triazine) 4- dalapon at 5 + 10 4–10 kg/ha and paraquat (1, l,-dimethyl-4, 4,-bipyri-dinium ion) + diuron + DSMA (disodium methauearsonate) proved most effective in killing the canal bank weeds.
