Therefore, early detection and treatment of new invasions is most critical. The native rust pathogen, Puccinia thlaspeos stunts growth and can minimize seed production of dyer's woad. However, this rust is not widespread and may not reach many infestations. Currently, research is being conducted to evaluate the possibility of direct application of rust spores for biological control. Sheep grazing may also provide limited control of dyer's woad.
Sheep readily consume top growth of woad until the flowering stage.
Recent studies suggest that properly timed grazing, repeated several times per season may increase mortality and reduce reproductive performance when at least 60 percent of the plant is removed. Biological controls alone will not eradicate dyer's woad but may provide some control. Conclusions Early recognition and immediate treatment are the most important means of controlling dyer's woad. Awareness is the best defense against future infestations. The Dyer's Woad Awareness and Eradication Program was initiated by MSU in cooperation with the Montana Department of Agriculture to prevent further invasion of dyer's woad.