As I can remember well, You can find two methods for Streptomyces scabies isolation in: Schaad N.W., J.B. Jones, W. Chun, Laboratory Guide for Identification of Plant Pathogenic Bacteria, ed.3; 2001.

I have used both methods for isolation pathogenic Streptomyces but I have obtained many different cultures, mostly not pathogenic. In my research the method with a part of tissue incubated in water bath in 60 deg. C was more effective (greater number of isolates).