EFFECT OF CERCOSPORA BLIGHT, INDUCED BY CERCOSPORA-CAROTAE, ON DEVELOPMENT, GROWTH AND YIELD OF CARROT

The objective of this study was to quantify the effect of Cercospora b light of carrot (Cercospora carotae) severity on development (vegetati ve stages), growth (dry weight of leaves and roots, leaf area index) a nd yield of carrot (Daucus carota var, sativa). In experiments conduct ed on organic soils during 1990, 1991 and 1992, three levels of diseas e severity were obtained by different number of fungicide applications : no application, two or three applications, and weekly applications. During the three years, significant differences were observed at 60 d ays after sowing for disease severity, at 80 days after sowing for the dry weight of leaves and leaf area index, and at 100 days after sowin g for the dry weight of roots. An increase in the number of fungicide applications resulted in an increase in total yield at final harvest. However, weekly fungicide applications did not result in an increase i n yield of carrots in the regular size classification, it is thus poss ible to maintain an acceptable economic yield even if the number of fu ngicide applications is reduced.