A series of experiments was conducted to assess the effect of different levels of initial anthracnose inoculum (as transplanted infected seedlings) on final infection and yield of lupins. The influences of environment and cultivar resistance on anthracnose infection were also examined. Anthracnose infection caused significant yield reduction at a range of sites. Disease incidence was higher and yield reduction greater when initial inoculum was increased. Yield reduction was less in cv. Wonga (resistant) than in either cv. Myallie (susceptible) or cv. Kiev Mutant (extremely susceptible). Stem tissue of Wonga was more resistant to infection than pods. Higher rainfall resulted in more anthracnose infection and greater yield reduction. Infection spread further with greater wind strength and was more severe in warmer temperatures. Cultivar resistance and environment influenced the effect of initial anthracnose inoculum on crop infection and yield.