The benefits of seed treatments to plant emergence and root necrosis were investigated in fields with mixtures of seedling disease pathogens and fields with one seedling disease pathogen (Thielaviopsis basicola). In fields with mixtures of seedling disease pathogens disease control was inadequate, while with T. basicola alone, control was adequate. In growth chamber experiments using naturally infested field soil with either mixtures of pathogens or T. basicola alone, plant emergence was unaffected by seed treatment and emergence was worse for the mixed pathogens than the single pathogen. Root necrosis was reduced in the case of T. basicola alone when seed was treated with Nuflow M, but not with combinations of Captan, Vitavax-PCNB, or Apron. Soil (sterilized) was infested with T. basicola or Pythium or both and emergence, root length, and root necrosis was compared with different seed treatments. An interaction between the two fungi was found with respect to root length and root necrosis, however the nature of that interaction (+/-) was inconsistent between experiments. Composite soil samples were taken during a survey from 102 fields in west Texas and seed treated with fungicides active only on Pythium, or Rhizoctonia solani, or neither were planted in the soil and held under cool, wet conditions. Field samples were divided into categories of low or high root necrosis, and emergence was compared to determine if root necrosis was associated with cotton seedling disease. There was no association of plant emergence with root necrosis.