Northern corn leaf blight (NCLB) (Figure 1) has been reported from several fields in southern Iowa. You will remember that this disease was widespread in Iowa in 2014, and severe on susceptible hybrids. Since the fungus survives the winter in corn residue, we likely have above normal inoculum present. Cool weather with frequent precipitation favors infection of corn by the fungus and disease development. New lesions may develop every 4 days (Muiro et al., 2010) when conditions are favorable (susceptible hybrid, cool and wet weather). Warm dry conditions will slow or halt disease development until favorable conditions return.