broomrape control in sunflower with glyphosate

sunflower (helinathus annuus) is a susceptible host to the holoparasite hemp broomrape (orobanche ramosa) in central parts of iran, causing yield loss due to severe infestations. a field study was conducted in 2006 to evaluate the efficacy of glyphosate for controlling the parasitic weed hemp broomrape in sunflower. glyphosate was applied once or twice at five rates ranging from 0.075 to 0.450 kg ae ha-1. most efficient control was obtained from once or twice application of gyphosae at 0.225 and 0.350 kg ae ha-1 at both application times. there were a significant reduction in hemp broomrape dry weight at 0.225 and 0.350 kg ae ha-1 (75 and 87.5 %), respectively compared to control. glyphosate at 0.075 kg ae ha-1 was not sufficient enough to provide acceptable control, but duplicating the application of this rate provided good control of weed. nearly no hemp broomrape shoot and dry weight were measured when glyphosate was applied twice at 0.450 kg ae ha-1. however, sunflower grain yield loss (63%) resulting from glyphosate toxicity at 0.450 kg ae ha-1 was observed when applied twice, compared to its application at 0.225 kg ae ha-correspondence to: y. filizadeh, [email protected]   results showed that hemp broomrape was unable to survive after the twice application of glyphosate at 0.225 or 0.350 kg ae ha-1.