A survey was made of certain wild and cultivated grasses in Alberta in order to ascertain to what extent they are harboring fungi capable of causing foot rots of wheat. Quack grass, Agropyron repens, and western rye grass, Agropyron tenerum, were found to be particularly important in this respect. Both were found heavily attacked under natural conditions with strains of the take-all fungus, Ophiobolus graminis, which proved capable of causing as severe damage to wheat as strains from wheat. Strains of Helminthosporium sativum which proved highly pathogenic to wheat were also isolated from these two grasses. Strains of Fusarium obtained from A. repens and A. richardsonii caused little or no damage to wheat.Agropyron repens is already an important weed in central Alberta. It was found infesting cultivated fields in summerfallow as well as those in crop. In summerfallow this weed appears to encourage the survival of Ophiobolus graminis, while in wheat fields infected quack grass was found associated with severe take-all damage to the crop. Agropyron tenerum is one of our most popular forage grasses and occurs commonly as a wild native plant in Alberta. Observations indicate that in the moister parts of the province wheat following this grass in rotations may be severely injured by take-all. In a rotation at the University of Alberta, wheat showed little or no take-all damage after timothy and alfalfa, moderate damage after brome grass and severe damage after western rye grass. In this experiment western rye grass itself was almost killed out prematurely in all replicates, apparently by the take-all fungus.Artificial inoculation of the various grasses was made with wheat strains of foot-rotting fungi by adding inoculum to the soil. All species of Agropyron tested including crested wheat grass, Agropyron cristatum, proved highly susceptible to Ophiobolus graminis, moderately susceptible to Helminthosporium sativum, but only slightly susceptible to Fusarium graminearum, though the latter was responsible for considerable non-emergence of the seedlings. Bromus inermis and B. ciliatus proved quite susceptible to all three pathogenes. Hordeum jubatum was heavily attacked by Ophiobolus graminis but not by the other two fungi. Avena sativa was not attacked by O. graminis and only slightly by H. sativum and F. graminearum, while timothy, Phleum pratense, appeared immune from all three fungi.