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Cultural Management
Japanese stiltgrass is introduced into turf stands primarily through transfer of seed on maintenance equipment, shoes, animal fur, in soil used for renovation projects, and by other means. Although there is no practical way to detect seeds in soil, using soils from sites with no previous history of Japanese stiltgrass infestation can lessen the chances of contamination of turfgrass sites. If only a few Japanese stiltgrass plants are infesting a lawn, they can be removed by hand pulling soon after leaf emergence in spring and before seedheads form later in the growing season. Improving turf density through fertilization, removing trees or trimming branches to reduce shading, and use of turfgrasses well-adapted to site conditions will help slow
the spread of Japanese stiltgrass but may not provide effective suppression once this weed is well established. If infestations occur in lawns, mow frequently to prevent seedheads from forming and producing seeds. If seedheads are observed in lawns during late summer and fall, bagging and removing mower clippings from the site may help to reduce further seed dispersal.

Chemical Control
Japanese stiltgrass can be controlled with certain preemergence herbicides if applications are properly timed. Since the seed of this species begins to germinate before crabgrass, preemergence herbicides should be applied 2 to 3 weeks earlier than dates recommended for crabgrass control. Active ingredients that have shown consistent preemergence control of Japanese stiltgrass (86% control or greater) include prodiamine (Barricade and
other prodiamine-containing products), pendimethalin (Pre-M, Pendulum, and other pendimethalin-containing products), and dithiopyr (Dimension and other dithiopyr-containing products) (Judge et al., 2005). As of this writing, dithiopyr products are the only preemergence herbicides labeled for Japanese stiltgrass control (listed on labels as Mary's grass and Microstegium vimineum).

AS WITH ALL HERBICIDES , MAKE SURE YOU FOLLOW THE DIRECTIONS ON THE LABEL

Selective postemergence herbicides are generally less effective in controlling Japanese stiltgrass when compared to preemergence herbicides, but some can provide greater than 50% control if applied to young plants up to the 3- to 4-tiller growth stage.

Fenoxaprop-p-ethyl (Acclaim Extra) and topramezone (Pylex) are the only postemergence herbicides labeled for control of Japanese stiltgrass in cool-season turfgrasses. Be sure to follow label precautionary statements, restrictions, and directions regarding rates and timing of applications when using these herbicides. On infrequently mowed fine fescue
rough areas on golf courses, sethoxydim (Segment II and Sethoxydim SPC) and fluazifop-p-butyl (Fusilade II) can provide good control of Japanese stiltgrass when two applications are made at 4-week intervals to plants that are 6 to 7 inches in height (Judge et al., 2005). However, Japanese stiltgrass is not listed on the labels of these herbicides.

The above information is from Lawn and Turfgrass Weeds: Japanese Stiltgrass [Microstegium vimineum (Trin.) A. Camus] - Penn State University Extension at the link below:

Lawn and Turfgrass Weeds: Japanese Stiltgrass [Microstegium vimineum (Trin.) A. Camus]