Non-traditional methods of applying Ridomil Gold (mefenoxam) to tobacco for control of black shank, Phytophthora nicotianae var. nicotianae, were explored in four years of field trials in Tennessee. Applications in the transplant water (TPW) at 0.5 pt/acre (A) or in an over-the-top band (OTB) at 0.5 pt/A immediately after planting were tested for crop safety in two black shank-free sites. Leaf yield and quality of burley tobacco and leaf yield of dark tobacco were not adversely affected by either treatment. Leaf quality of dark tobacco was reduced (P = 0.05) by TPW 0.5 pt/A, in one trial. Efficacy trials were conducted on farms. Under severe black shank pressure, a combination of TPW 0.25 pt/A with OTB 0.5 pt/A provided better control (79.2%) than TPW 0.5 pt/A (42.6%) or OTB 0.5 pt/A (4.4%). The incidence of black shank for OTB 0.5 pt/A was 72.1% lower in the presence of TPW 0.25 pt/A than in the absence. The incidence of black shank for TPW 0.25 pt/A was 35.3% lower in the presence of OTB 0.5 pt/A than in the absence. An application of Ridomil supplemental to the TPW is considered necessary in most cases; however, an attempt to determine optimum timing was unsuccessful because of uneven distribution of the disease in the test area. ProPhyt (phosphorous acid) was also tested as a TPW treatment at 3 pt/A and provided a level of black shank control that was almost as good as Ridomil. No visible phytotoxicity occurred in any of the treatments in the eight trials. (Reprinted with permission)