SUSCEPTIBILITY OF SOME PLUM VARIETIES TO MAIN DISEASE ATTACKS AT THE VOINESTI STATION DURING 1955–1967
Although they have the best climatic conditions for their development, plum trees loose in most years nearly 17–81 per cent of their yield on account of severe disease attacks.
Fifty-seven plum varieties (tables 1 and 2) have been taken into study at the Voinesti station, in order to be zoned.
Specialists of the biology, selection and breeding laboratory have studied in these orchards the economic and biologic value of each variety (D. Cvasnîi, C. Radulescu, St. Nica, Gh. Moruju and N. Mateescu) (2).
The plant protection laboratory of the Voinesti Station studied the susceptibility of the 57 plum varieties to the main diseases, with a view to differentiating control measures.
Investigations undertaken in the U.S.S.R., France, Germany, Socialist Republic of Romania etc. enabled to put forward the assumption that plant resistance to diseases is strongly correlated with: 1) the pH of cell sap (11); 2) transpiration intensity (12); 3) respiration intensity (10); 4) presence of anthocyan (14); 5) ability of the plant to kill germs (16); 6) osmotic pressure (16); 7) anatomic structure (thickness of cuticle layer in the leaves, size and location of stomata, their number on the limb (16;8) etc.