General Information

General Information

Weedmaster herbicide is a selective postemergence herbicide for controlling a wide spectrum of annual, biennial, and perennia broadleaf weeds and brush in grass forages and selected row crops.

Mode of Action

Weedmaster contains two active ingredients: dicamba and 2,4-D. Weedmaster is readily absorbed by plants through shoot and root uptake, translocates throughout the plant's system, and accumulates in areas of active growth. Weedmaster interferes with the plant's growth hormones (auxins) resulting in death of many broadleaf weeds.

Application Instructions

Apply Weedmaster at the rates and growth stages listed in Table 1 and Table 2 as follows unless instructed differently by Food/Feed Crop-specific Informations or Nonfood/Feed Use-specific Information. Applications can be made to actively growing weeds as aerial, broadcast, band, or spot spray applications. Weedmaster may be applied using water or sprayable fluid fertilizer as a carrier. Sprayable fluid fertilizer may be used as the carrier in preplant or preemergence uses for all crops listed on the label. Postemergence uses with sprayable fluid fertilizer may be made on pasture, hayland, or wheat crops only.

The most effective application rate and timing varies based on the target weeds species (refer to Table 1 and Table 2). In mixed populations of weeds, thte correct rate is determined by the weed species requiring the highest rate.

Delaying application permits weeds to exceed the maximum size stated and will prevent adequate control.

All aerial and ground application eqduipment must be properly maintained and calibrated using appropriate carriers or surrogates.

Susceptible Plants

DO NOT apply under circumstances where spray drift may occur to food, forage, or other plantings that might be damaged or crops thereof rendered unfit for sale, use or consumption. Susceptible crops include, but are not limited to, cotton, okra, flowers, grapes (in growing stage), fruit trees (foliage), soybeans (vegetative stage), ornamentals, sunflowers, tomatoes, beans, and other vegetables, or tobacco. Small amounts of spray drift that might not be visible may injur susceptible broadleaf plants.

Limitations, Restrictions, and Exceptions

Do not graze or harvest for livestock feed prior to crop maturity.

Do not use Weedmaster in wheat underseeded with legumes.


Weedmaster can be used to control weeds that may interfere with harvest of wheat. Apply Weedmaster as a broadcast or spot treatment to annual broadleaf weeds when wheat is in the hard dough stage and the green color is gone from the nodes (joints) of the stem. Best results will be obtained if application can be made when weeds are actively growing but before weeds canopy.

A waiting interval of 7 days is required before harvest.

Do not use preharvest-treated wheat for seed unless a germination test is performed on the seed with an acceptable result of 95% germination or better.

For control of additional broadleaf weeds or grasses, Weedmaster may be tank mixed with other herbicides such as Ally or Roundup Ultra that are registered for preharvest use in wheat.

Preharvest use of Weedmaster is not registered for use in California.

Restricted Entry Interval

48 hours