Effects of exogenously supplied cAMP on sclerotial development in S. sclerotiorum (S. s.) 1980, 192, 222, and 278, S. trifoliorum (S. t.) 246, S. minor (S. m.) 240, and R. solani (R. s.) PR45. All cultures were grown on PDA amended with 10 mM cAMP in 24-well culture plates as described in Materials and Methods.