Broadleaf weeds and sugar beet response to phenmedipham, desmedipham, ethofumesate and triflusulfuron-methyl

The sugar beet plant is a poor competitor against weeds. Uncontrolled weeds that emerge with the crop typically cause from 50 to 100% yield loss. Field studies were conducted from 2002-2004 to investigate the effects of different rates (1/1, 3 / 4 , ½) of herbicides on broadleaf weed control and yield of sugar beet. Phenmedipham + desmedipham + ethofumesate, triflusulfuron, metamitron, chloridazon, chloridazon + quimerac and oil-seed rape oil (1.0 1 ha -1 ) were applied three times at 10 to 15 days intervals starting at the cotyledon growth stage of weeds at 91+71+112, 15, 700, 650, 540+90 g a.i. ha -1 dosage (full rate). All rates of herbicides phenmedipham + desmedipham + ethofumesate had a low efficacy. The addition of triflusulfuron to this herbicide reduced the amount of Tripleurospermum perforatum, Thlaspi arvense, Viola arvensis and Polygonum aviculare, but didn't affect Chenopodium album, Lamium purpureum. Weed control by applying phenmedipham, desmedipham, ethofumesate and triflusulfuron had increased from 5.5 to 58% by the addition of metamitron, chloridazon and chloridazon+quimerac. The dry-weight of weeds varied significantly depending on the'herbicide rates used. Using ½ of full (1/1) rates of the herbicide phenmedipham + desmedipham + ethofumesate had a low efficacy. All herbicide treatments produced higher sugar beet root and sugar yields than did phenmedipham + desmedipham + ethofumesate. Non-sugars were not affected by the herbicide treatments.