ABSTRACT
Observations made for several years in three lemon groves in Patras and Poros areas of Peloponnessus in Greece, showed that Mal secco disease has a rapid and increasing intensity when frosts are preceded, while mild winters reduce disease intensity. Significant negative correlation was found in disease intensity versus yield, reducing yield more than 50% when disease index is over 2,5 in a scale 0-5. With the exeption of cv Lapithos which showed resistance to the disease hut has not good lemon quality, all other cvs tested, Adamopoulou, Karystini, Maglini and Santa Tereza, showed various degrees of sensitivity. Rootstocks, Troyer, Volkameriana and Sour Orange had not found to have any particular influence on disease development; Troyer seems to be more sensitive than other two rootstocks. The combination Maglini on Troyer showed higher disease intensity and development.
