Recent studies have reported S. sclerotiorum (Lib.) de Bary as an emerging pathogen of sugar beet (Beta vulgaris L.) causing leaf blight, seedling damping-off and root necrosis, becoming a fundamental production problem in the Red River Valley of North Dakota and Minnesota. The continuous spread of this pathogen's damaging impact across sugar beet-producing states necessitates proactive management measures to reduce the risk of potential outbreaks. This study aimed to (1) assess inoculation methods for sugar beet reaction to S. sclerotiorum, varietal response and cross-infectivity, and (2) evaluate fungicide efficacy against Sclerotinia diseases in three sugar beet varieties. Disease evaluation was measured as lesion size. Results from this study indicated that colonized barley inoculum was particularly effective in causing leaf blight on sugar beet plants (P= 0.05). Crystal M837 variety showed reduced susceptibility to Sclerotinia leaf blight. ACH 166 and Beta 7029 were moderately susceptible to leaf blight, but for root infection, they showed reduced susceptibility which was significant at all stages during the fungicide efficacy study (P= 0.05). Proline and Priaxor provided the most effective control against Sclerotinia leaf blight and root necrosis in sugar beet (P= 0.05). These findings offer critical insights into sugar beet variety and fungicide selection for effective control of S. sclerotiorum. Also, vital information about the cross-infectivity status of major host crops (soybean, sunflower and canola) provides valuable information for crop rotation decisions towards mitigating losses caused by S. sclerotiorum. This study gives a first look into managing S. sclerotiorum, an emerging pathogen of sugar beet and a potential threat to the sugar beet industry.