STUDY ON PEACH AND NECTARINE CULTIVARS SUSCEPTIBILITY TO THE MAIN FUNGUS AND BACTERIA

In both plots 2 trees for each variety were planted. In one field a normal spray program was applied (insecticides and fungicides) while in the other field only insecticides were used.

For 4 years data on the following parasites attacks were recorded:

• Coryneum beijerinckii Oud. (Peach blight)
• Monilia laxa (Aderh. Ruhl.) Honey (Brown rot)
• Sphaerotheca pannosa (Wallr.: Fr.) Lev. (Powdery mildew)
• Tranzschelia pruni-spinosae (Pers.) Diet. (Rust)
• Taphrina deformans (Berk.) Tul. (Peach leaf curl)
• Xanthomonas campestris p v. pruni (E. F. S.) Dows. (Bacterial leaf spot).

Sensitivity of the cultivars to the parasites was estimated by observing macroscopic symptoms on trunks, branches, flowers and leaves. Evaluation of the susceptibility was carried out scoring symptoms from 0 to 5. (0= no symptoms, 5= maximum sensitivity).

All peach and nectarine varieties were highly susceptible to the parasites. Only 4 peach varieties and 3 nectarines were evaluated little sensitive to X. pruni.

Only one nectarine variety showed to be resistant to Tranzschelia pruni-spinosae, and to Coryneum beijerinckii.