Alternative methods of weed control for carrot production

Experiments were conducted to study alternative methods of weed control in carrot. Several herbicides were tested in Michigan between 2001 and 2003 for preemergence and postemergence weed control in carrot. Preemergence clomazone and flufenacet plus metribuzin (DomainRTM) were consistently safe on carrot and provided good weed control during the production season. Carrot stand counts and yield in these herbicide treatments were similar to linuron treatment in all sites and years. Oxyfluorfen postemergence was safe on carrot and also gave good weed control.; In another experiment, an air-assisted rotary atomizer sprayer was compared to a conventional boom sprayer. Herbicide application effectiveness did not differ between the conventional sprayer and the rotary atomizer sprayer. However, this sprayer used a fourth of the amount of liquid compared to the conventional sprayer, an advantage of fewer refill trips required.; Flame weeding was studied as an alternative method of weed control. Broadleaf weeds with unprotected growing points were more susceptible to heat than grass weeds with protected growing points. Furthermore, weeds at earlier developmental stages were more susceptible to heat than weeds at older stages. In general, better weed control was obtained when weeds were flamed at the 0-2 leaf stage.