Percent recovery of symptomatic leaf populations of strains in plots with a mixture of mutant strains (Mut-A, ▪; Mut-B, Δ; Mut-C, ×; Mut-ABC, ○) and with a WT T1 (⧫) and T3 (•) strain in the field. A, spring 2001; B, fall 2001; C, fall 2002. DAT stands for days after transplanting.