IT has been shown by S. D. Garrett (Ann. App. BioL., 35, No. 14-17 March 1948) that the severity of root attack by the take all fungus, Ophiobolus grapuinis, is reduced by applications of nitrogen, and by commed dressings of phosphate and potash. This slate of affairs was observed in field experiments, but not in pot cultures where the fungus was in-oculated on the crowns of barley plants. The discrepancy is interpreted by assuming that in the field the added fertilizers stimulate the plant to make new roots faster than the fungal parasite can attack them, and so the host 'escapes' from the fungus.