SUMMARYThe eradicative and protective activities of the salicyl‐, 3‐chlorosalicyl‐, 5‐chlorosalicyl‐ and 3,5‐dichlorosalicyl‐anilides and‐para‐chloroanilides, against cucumber powdery mildew (Erysiphe cichoracearumDC.) and tomato leaf‐mould (Cladosporium fulvumCke.) have been determined byin vivoglasshouse tests on pot plants. No compound was more effective than salicylanilide against either disease at a non‐phytotoxic concentration.In addition, thein vitrofungitoxic activities of these compounds against spores of tomato leaf‐mould have been determined; several were considerably more act