The effect of seeding rate and seed treatment of the systemic insecticide Gaucho 480 (imidacloprid) on aphid abundance, incidence of barley yellow dwarf infection, and yield of winter wheat was studied. Trials were conducted near Tifton, Plains, and Griffin, GA in 2004 and 2005. Aphid numbers per unit area were similar among seeding rates but were greater per plant at lower seeding rates. Likewise, BYD incidence was greater at lower seeding rates. Gaucho ST reduced aphid numbers at 30 days after planting at all locations but only suppressed BYD incidence at Griffin. Yield declined at the lowest seeding rate (10 seeds/ft2) but wheat compensated by producing more tillers per plant at seeding rates of 20 – 40 seeds/ft2. Seeding rates of winter wheat can be reduced without affecting yield potential, but reducing seeding rate increases the potential risk of BYD infection. Gaucho insecticide was not effective in suppressing BYD incidence but may be useful in controlling aphids and suppressing BYD at Griffin and areas northward.