Effect of mannich bases on some plant pathogenic fungi

3-(2-Pyridyl)-3-iminoisatin, 1-piperidinomethyl-3-(2-pyridyl)-3-iminoisatin and 1-acetyl-3-(2-pyridyl)-3-iminoisatin affect spore germination of Alternaria alternata, A. carthemi, Curvularia lunate, Fusarium oxysporum f.sp. ciceri and F. udum and influence the development of powdery mildew (Erysiphe pisi) on pea under glasshouse condition as well as conidial germination of E. pisi on excised pea leaves. Spore germination was inhibited in the sequence 1-acetyl-3-(2-pyridyl)-3-iminoisatin > 1-piperidinomethyl-3-(2-pyridyl)-3-iminoisatin > 3-(2-pyridyl)-3-iminoisatin followed the order accordingly The powdery mildew development and conidial germination of E.pisi 1-piperidinomethyl-3-(2-pyridyl)-3-iminoisatin > 1-acetyl-3-(2-pyridyl)-3-iminoisatin > 3-(2-pyridyl)-3-iminoisatin. The chemicals were compared with commonly used antifungal fungicides.