Abstract

A field experiment was conducted at the experimental farm, Department of Field Crop Science , College of Agriculture , during spring and summer season of 2005 to investigate the efficacy of some commercial formulation of Trifluralin namely, Agrotrifluran, Califort 48 EC, Flural, Trifluralin and Trifluralin 48 EC to control sunflower‘s weed. Herbicides used with three application rates 2000, 2400 and 2800 cm3.ha 1. Results revealed that herbicides affect broad and narrow leaved weeds by inhibition of their dry weight by 100% and also reduced the dry weight of Johnson grass by 12.1% , 14.7% , 14.7% , 12.4%, and 17.1%respectively in spring season. Herbicides Califort 48 EC and Trifluralin 48 EC reduced dry weight of Johnson grass in summer season by 14.6% and16.3% respectively according to weedy treatment. Application of these formulations have improved all investigated characters of sunflower plant. All herbicides caused increasing the height plant by 143.4, 140.8, 141.4, 142.9and144.3 cm respectively in spring season and by 143.8, 141.4,142.7,143.3 and145.4 cm in summer season while the weedy treatment gave lowest value of height plant. Herbecides caused increasing diameter by 21.9 - 24.0% in spring season and 28.1-28.8% in summer season. Trifluralin 48 EC and Flural 48EC gave the highest number of seed in plate in two seasons 1228.4, 1218.3, 1249.9 and 1243.6 seed/plate respectively. The herbicides Agrotrifluran, Califort 48 EC, Flural, Trifluralin and Trifluralin 48 EC gave high value of yield by 4.1, 4.0,3.9, 4.1,4.1ton/ha-1 respectively in spring season while in summer caused increasing of yield by 4.3, 4.3 ,4.1 ,4.2 and 4.3 respectively according to the weedy treatment.