Oust^® XP is a preemergence and postemergence herbicide that controls many annual and perennial grasses and broadleaf weeds in forestry and non-crop sites.

Oust XP is a water-dispersible granule containing sulfometuron-methyl (Group 2 herbicide).

Oust XP herbicide is mixed in water and applied as a spray or impregnated on dry, bulk fertilizer. Apply sprays by ground equipment or by helicopter or as otherwise directed by Special Local Need labeling. Apply impregnated fertilizer by ground equipment or by air (helicopter or fixed-wing aircraft). See the product label for application rates and mixing instructions.

When applied as a spray, Oust XP herbicide is absorbed by both the roots and foliage of plants, rapidly inhibiting the growth of susceptible weeds. The active ingredient in Oust XP herbicide blocks cell division in the weed's active growing areas of stems and roots. When applied on dry fertilizer, Oust XP is absorbed primarily by the roots. Two to 3 weeks after application to weeds, leaf growth slows, and the growing points turn reddish-purple. Within 4 to 6 weeks of application, leaf veins and leaves become discolored, and the growing points subsequently die.

Oust XP herbicide can be applied to control many annual and perennial grasses and broadleaf weeds in forestry and non-crop sites. It may be used for general weed control on terrestrial non-crop sites and for selective weed control in certain types of unimproved turf grasses on these same sites. Oust XP may also be used for selective weed control in forest site preparation and in the release of certain conifers and hardwoods.

Oust XP can be applied near or around bodies of water, but not applied directly to water. Do not apply Oust XP herbicide to natural or man-made bodies of water such as lakes, reservoirs, ponds, streams, and canals. Oust XP may be applied on forestry and non-agricultural sites that contain areas of temporary surface water caused by collection of water between planting beds, in equipment ruts, or in other depressions created by management activities. It is permissible to treat intermittently flooded low lying sites, seasonal dry flood plains, and transitional areas between upland and lowland sites when no water is present. It is also permissible to treat marshes, swamps, and bogs after water has receded, as well as seasonally dry flood deltas.

Oust XP herbicide controls tough annual and perennial grasses and broadleaf weeds, including the following. See the product label for a complete list. Do not use on crops.

Broadleaf weeds: Annual sowthistle, chickweed, curly dock, dogfennel and more

Grassy weeds: Annual bluegrass, barnyardgrass, foxtail fescue, Italian ryegrass and more

When applied as spray, Oust XP herbicide controls weeds by both preemergence and postemergence activity, so the best results are obtained when it’s applied before or during the early stages of weed growth, before weeds develop an established root system.

When applied on dry fertilizer, the best results are obtained when the application is made before weed emergence. For preemergence control, moisture is required to move Oust XP into the root zone of weeds, so it must be activated by rainfall or overhead irrigation before weeds become well established.

Oust XP herbicide can be tank-mixed with other herbicides registered for use in forestry and non-crop sites. Read and follow the applicable restrictions and limitations and directions for use on all product labels involved in tank-mixing. Users must follow the most restrictive directions for use and precautionary statements of each product in the tank mixture. It is the user’s responsibility to ensure that all products are registered for the intended use.

Oust XP herbicide will remain active for up to 12 months after application. If non-crop or forested sites treated with Oust XP are to be converted to a food, feed, or fiber agricultural crop, or to a horticultural crop, do not plant the treated sites for at least one year after application. A field bioassay must then be completed before planting crops.