The work presents data about the behavior in respect to powdery mildew disease (Podosphaera leucotricha Ell. et Ev. Salmon) of Ionatan, Florina, Romus 2, Pionier and Delicios de Voineşti apple varieties. The varieties were chosen so they can be as heterogeneous as possible for the performance to powdery mildew disease. It is necessary to mention that there were other observations performed by the members of the phytopathology department in other years. The orchard in which observations were made is an intensive apple orchard, where in recent years has made minimal treatments against diseases and pests, namely one winter treatment and four treatments in vegetation, but in 2009 were added two vegetation treatments. Observations were made on five trees in three repetitions, it was noted the frequency, intensity and was calculated in the final level of appeal. The frequency was noted by percentile and the intensity was scored by a scoring scale from 0-6. Degree of attack was calculated by well known classical formula. Results were compared with the average experience in the end. At fungus attack, the best performances were registered, as expected, at Romus2 and Florina varieties. The results were satisfactory for Delicios de Voinesti. Ionatan variety confirmed that it has the most sensitive variety at the fungal attach from Podosphaera leucotricha Ell. et Ev. Salmon. After the study we concluded that 7 treatments a year are not enough for having a healthy culture, that the inoculators source is consistent, that at Ionatan variety the disease is chronic. We recommend that a special attention should be given to Ionatan variety for powdery mildew disease even from the first year from planting if there is a desire for a healthy orchard from phythosanitary point of view.

Podosphaera leucotricha; apple powdery mildew; fungal diseases

Presentation: oral