Figure 18. A 1 to 9 scale is used for rating a range of plant reactions to Stewart's wilt (1 = very little movement of E. stewartii from infection sites, 9 = dead plants). Plant breeders and pathologists select materials that have non-systemic reactions (ratings below 3.5 on this scale) in order to develop corn lines with levels of Stewart's wilt resistance that prevent or greatly inhibit yield losses. (Courtesy J.K. Pataky) BACK