Figure 40. Races of Phytophthora nicotianae present in tobacco-growing regions of the US, can be identified based on a reaction on a set of host differentials. A. Healthy plants, prior to inoculation. B. Race 0, the wild-type, can cause disease only on the susceptible cultivar Hicks. C. Race 1 can cause disease on Hicks (susceptible), NC 1071 (single-gene resistance from N. plumbaginifolia), and KY 14xL8 (single-gene resistance from N. longiflora). D. Race 4 can cause disease only on Hicks (susceptible) and KY 14xL8 (single-gene resistance from N. longiflora). BACK