Resistance of Different Tomato Varieties against Tomato Powdery Mildew during Different Growth Stages

The pathogen of tomato powdery mildew (Oidium neolycopersici Kiss) was simultaneously inoculated into four varieties during seedling,flowering and fruiting stages under the same environmental conditions by inducing inoculation method,so as to study the resistance during different growth stages.Different varieties of plants and the plants during different growth stages were investigated after inoculation for 12 d,and disease epidemic curves were drawn according to survey data.The results showed that different varieties performed different resistance against powdery mildew and the same variety also showed different resistance during different growth stages.The susceptible extent of Lujia was the heaviest during seedling and flowering sages,while it showed the strongest resistance during fruiting stage ;improved 96-8 showed the highest resistance during seedling stage,but performed the lowest resistance during fruiting stage.