BROWN ROT BLOSSOM BLIGHT AND FRUIT ROT INCIDENCES OF APRICOT IN TWO DIFFERENT GEOGRAPHICAL REGIONS IN HUNGARY

The aim of our two-year study was to assess the incidence of brown rot blossom blight and fruit rot caused by Monilinia laxa in 2003 and 2004. Assessments of incidence were made on cultivar ‘Bergeron’ (susceptible to brown rot) in a flatland and a hilly growing area (at Cegléd and Gönc, respectively). In both locations, plant protection was performed according to the integrated fruit production guidelines and small untreated plots were set up for each cultivar in both years. In 2003, when weather conditions were dry and hot, brown rot incidence was low (less than 10%) on both blossoms and fruits. Monilinia laxa did not cause significantly different blossom blight and fruit rot at the hilly (Gönc) area compared to the flatland, even in untreated plots. However, in 2004, when spring and summer weather conditions were wet and cold, incidence reached 95% for blossom blight and 33% for fruit rot in the untreated plots. Blossom blight incidence was 1.5-2 times higher in the flatland area compared to the hilly growing area. During the blooming period of apricot, two (at the flower-bud stage and at full bloom) and three (at the flower-bud stage, at full bloom and at petal fall) fungicide applications were necessary for successful control at Gönc and Cegléd, respectively. The difference between the two orchards was due to the fact that blooming started one week later in the hilly region (at Gönc) than in the flatland region (at Cegléd); therefore, the critical weather period coincided only partially with blooming in the orchard in the hilly region. Fruit rot incidence was similar in both regions, since the amount and distribution of rainfall were similar during the fruit-ripening period.