From 1992 through 1997, five different over-the-top grass control materials have been effectively used to control Johnsongrass in test plots established in the Southern Rolling Plains of Texas. The level of Johnsongrass control has been higher than 90 percent when herbicides were applied to unstressed, actively growing plants, less than ten inches in height. Staple® (Pyrithiobac-sodium), an over-the top broadleaf weed control herbicide used in cotton, was tank mixed in 1995 with one of the grass control materials and a ten percent reduction in Johnsongrass control occurred. To alert producers of the reduced Johnsongrass control resulting from tank mixing Staple, tests were established in 1996 and 1997. In the established tests, the reduction in Johnsongrass control was less than expected, ranging from none to nine percent.