Figure 13. (A) A simple microscopic examination of symptomatic leaf tissue for bacterial ooze can be used to diagnose Stewart's wilt. A section of symptomatic leaf tissue is placed in a drop of water on a microscope slide. (B) When viewed with a compound microscope, bacteria are observed as they ooze from xylem vessels of plants infected with Erwinia stewartii. (Courtesy J.K. Pataky) BACK