Variable Cultivar Response to Control of Powdery Mildew in Coriander (Coriandrum sativumL.)

Different spray schedules of Dinocap tested for control of powdery mildew (Erysiphe polygoni DC) in coriander (Coriandrum sativum L.) demonstrated that disease control varied with cultivars differing in maturing periods. The late-maturing cultivar had the greatest differnce in disease severity, seed yield, 100-seed weight and oil yield between fungicide treated and untreated plots. Weekly applications of Dinocap provided greater disease control and substantial increase in yield compared to bi-weekly applications in late-maturing cultivars. No such additional yield advantages were obtained on treatment of early-maturing cultivars. These results suggest the importance of frequent applications of fungicide to achieve better disease control and higher yield in late-maturing cultivars but indicate that such tactics may be economical in early-maturing cultivars.