Herbicide Activation with Drip Irrigation in Celery

In nearly $0.5 billion California fresh market celery herbicides have been commonly applied with or activated with overhead irrigation, causing significant runoff, which contains nutrient and pesticide contaminants.  Drip-line irrigation is already being used as precise irrigation alternative, which made the testing of herbicide safety and efficacy in drip-only systems necessary. Goaltender (oxyfluorfen) at 0.25 a.i. /acre and Chateau (flumioxazin) at 0.063 lb a. I /acre were applied one day prior to planting to either drip pre-irrigated and dry beds. The lack of crop injury and 83% to 87% weed control in both dry and drip pre-irrigated beds were similar to sprinkler activation of these herbicides conducted previously.  Lorox (linuron) at 1.85 lbs/acre and Caparol (prometryn) at 1.48 lbs/acre applied three weeks after transplanting, were also evaluated in drip-only irrigated celery. Both herbicides provided >90% control of five broadleaf weeds without significant injury to the crop. These studies showed that drip line irrigation was effective in its activation of currently available herbicides and flumioxazin that is scheduled to receive registration for celery in 2014.