Phytophthora root and stem rot (PRSR), caused by Phythophthora sojae, is infrequently encountered in Kentucky. However, where it does occur, the disease can be quite destructive. Soon after planting, P. sojae can cause damping-off of germinating seeds and/or young seedlings. Severe stand loss often necessitates replanting. Alternately, this pathogen can infect and kill established plants of susceptible soybean varieties any time during the season. Varieties that have some resistance to P. sojae may be stunted, but rarely die. PRSR is primarily a problem in poorly drained fields (due to high clay content, "hard pan," and/or soil compaction) or areas of fields that are prone to flooding.