Preemergence herbicide(s) should be applied after cane is packed and prior to weed emergence. Herbicide rate should be based on soil type and weed pressure. The high end of the herbicide rate range should be utilized for fields with clay soil types, fields with high organic matter, or with a history of heavy weed pressure. For most products, a minimum rainfall event of one-half inch within 10 to 14 days after herbicide application is necessary to ensure herbicide activation and optimal weed control.

Below are common preemergence herbicide programs used at planting. Herbicide rates are calculated for broadcast applications.

Command at 3.3 pt/a + Diuron/Direx/others 4L at 2.5 qt/a or Command at 3.3 pt/a + Metribuzin/others 75DF at 1.5 lb/a: Either combination provides excellent control of seedling johnsongrass, browntop millet, vaseygrass, Italian ryegrass, many annual grasses, and broadleaf weeds. They also provide good control of itchgrass and suppression of bermudagrass. Command can cause bleaching of sugarcane if soil cover is less than two inches.

Pendimethalin at 3 qt/a + Metribuzin/others 75DF at 2.5 lb/a: This combination provides excellent control of seedling johnsongrass, browntop millet, many annual grasses, and broadleaf weeds. It also provides good control of itchgrass and morningglories. Bermudagrass suppression is fair.

Pendimethalin at 3 qt/a + Atrazine/others 4L at 3 qt/a: This combination provides excellent control of seedling johnsongrass, browntop millet, many annual grasses, and broadleaf weeds. It also provides good control of itchgrass and morningglories but doesn’t control bermudagrass.

Metribuzin/others 75 DF at 3 lb/a: This herbicide provides excellent control of seedling johnsongrass, many annual grasses, and broadleaf weeds. Provides around 50% suppression of bermudagrass and unacceptable control of itchgrass.

Velpar at 1 qt/a or Velossa at 1.6 pt/a + Diuron/Direx/others 4L at 2.5 qt/a or Velpar at 1 qt/a or Velossa at 1.6 pt/a + Metribuzin/others 75 DF at 2 lb/a: Either combination provides excellent control of seedling johnsongrass, browntop millet, vaseygrass, many annual grasses, and broadleaf weeds. Provides suppression of itchgrass and bermudagrass. Crop injury can occur on course-textured soils with less than 1% organic matter and under heavy rainfall when applied to dry soil.

Dual II Magnum/Dual Magnum/others at 1 qt/a: This herbicide provides excellent control of browntop millet, vaseygrass, Italian ryegrass, and other annual grasses, divine nightshade, and other small-seeded broadleaf weeds. Provides yellow nutsedge and seedling johnsongrass suppression. This herbicide doesn’t provide acceptable control of itchgrass.

Treflan/Trifluralin/others at 2 qt/a: This herbicide provides excellent control of seedling johnsongrass, itchgrass, browntop millet, vaseygrass, and other annual grasses. Provides bermudagrass suppression. It must be incorporated within 24 hours after application. If incorporated too deep, damage may occur to sugarcane.

Spartan/others at 10-12 oz/a, Spartan Charge at 12.8-15.2 oz/a, Authority MTZ at 16-33 oz/a or Valor/others at 6-8 oz/a: These products control divine nightshade and many other broadleaf weeds. Spartan, Spartan Charge, and Authority MTZ will also provide nutsedge control.

For additional information, please refer to the Louisiana Suggested Chemical Weed Control Guide or the herbicide label.