Abstract: A rotating blowout preventor having a spring-steel reinforced stripper rubber removably mounted in a rotating inner housing, wherein the stripper rubber is sealed against the drill pipe by well bore pressure and externally-applied hydraulic pressure. In a preferred embodiment the externally-applied hydraulic pressure is maintained against the middle and upper portion of the stripper rubber by using a pump at a level of about ten percent above the well bore pressure to insure rotation of the stripper rubber with the drilling string and minimize rotation of the drill pipe inside the stripper rubber. A bayonet-type locking mechanism is attached to the stripper rubber for selectively removing the stripper rubber from the rotating inner housing and changing or repairing the stripper rubber.

Abstract: A method for biological control of pest grasses such as crabgrass using two species of a fungus selected from the genus Curvularia. The fungus is applied to the grass in amounts effective to produce typical plant lesions which kill or suppress, and thus control, the grass. The fungus may be administered with a surfactant or as granules, either of which may include additives such as glucose to enhance the pathogenic action of the fungus. Two species of the fungus are on deposit with the Department of Biological Sciences, Louisiana Tech University in Ruston, La. and with the International Mycological Institute in Surrey, UK and have been assigned the numbers MT-5 and CG-L.