diuron (Karmex or Direx)
Rate 1.2 to 1.6 lb ai/a (1.5 to 2 lb/a of the 80% DF)
Time Apply as soon after drill planting as possible, but before barley emerges.
Remarks For use in western Oregon and western Washington in winter barley. Make a single application of 1.5 to 2 lbs/a as soon as possible, but before barley emergence. A smooth, moist seedbed and moisture after treatment will enhance weed control. Restricted entry interval (REI) is 12 hours.
Caution Unless otherwise directed, do not use on spring barley. Do not replant treated areas to any crop within 1 year after the last application because injury to the subsequent crop may result.
Site of action Group 7: photosystem II inhibitor
Chemical family Substituted urea
metribuzin (several trade names)
Rate 0.75 to 8 oz ai/a (1 to 10.66 oz/a of the 75DF or 1.5 to 16 fl oz/a of the 4F)
Time Apply low rates (0.75 to 3 oz ai/a) when barley is in two-leaf to four-tiller growth stage. Apply 3 to 8 oz ai/a when barley has more than four tillers and secondary roots are longer than 1 inch, but before jointing growth stage.
Remarks May be used on spring and winter barley. Best control is on weeds less than 2 inches tall. Do not apply more than 8 oz ai/a in 1 year. Application rate also depends on organic matter content. If applying sequentially, allow at least 21 days between applications. At least 0.5 inch rain or irrigation is required within 2 to 3 weeks after application to move metribuzin into weed root zone. See label for more specific information. Restricted entry interval (REI) is 12 hours.
Caution Certain barley varieties should not be treated with metribuzin (refer to label). On irrigated cereals, do not apply more than 0.5 inch water for the first irrigation; in each additional irrigation, do not exceed 1 inch. Allow at least 14 days between the first and subsequent irrigations. Do not use on soils containing less than 0.75% organic matter. Do not rotate to wheat, barley, alfalfa or seed corn in the fall of the year following application, or in the spring of the following year. Do not apply through any irrigation system. Crop injury may occur if metribuzin is applied to frozen soil or crop still in winter dormancy.
Site of action Group 5: photosystem II inhibitor
Chemical family Triazinone