Management Recommendations for Microstegium Invasions
The most efficient way to manage invasive species is by Early Detection and Rapid Response (EDRR). To do this effectively, property managers need to know where to focus their search efforts for new invaders. This model should help to predict areas with high risk of invasion.
In general, the most likely sites to be invaded are those that are along corridors, such as roads, trails, and streams. Areas where water runs off from existing invasions and disturbed areas are also at high risk.
The surveys we have conducted of harvested sites suggest that the most successful way to minimize invasion of timber harvest sites is to eliminate Japanese stiltgrass in the log yard and other areas near the harvest site. Applying a grass-specific herbicide in these areas the season prior to harvesting could greatly reduce the seed bank and seed spread on machinery into the harvest site. This is a simple low-cost solution since the area to be treated prior to harvest is relatively small.
Other potential methods to reduce invasion are to add an annual seed mix to disturbed areas such as skidder trails and log yards after harvests and cleaning thorourghly cleaning equipment between sites.
Grass-specific herbicides are one of the most effective methods for removal of Japanese stiltgrass. They only affect grasses, so non-target effects are minimal. However, there are currently no grass-specific herbicides registered for use in wetland areas, so other methods may have to be used there. General herbicides, such as glyphosate, are not recommended because they will kill all plants, including natives, and the bare soil is likely to recolonized by invasive species (Flory 2008, 2009. Photo by Luke Flory).
Mowing can be effective if done before plants set seed in the fall. Mowing immediately after plants flower but before seed set is ideal, but mowing at any time in the season will significantly reduce seed production (Shelton, unpublished data).
Hand-pulling is effective for small patches, but recolonization by stiltgrass or other invasive species may happen in the disturbed soil. Because it is labor-intensive and a few missed plants will quickly recolonize the site (Flory & Clay 2009), it is not practical for larger patches. (Photo by Luke Flory)
A more comprehensive fact sheet on management of Japanese stiltgrass written by Luke Flory can be found here.