Area under disease progress curve and apparent infection rate of Alternaria blight of marigold incited by Alternaria tagetica at different planting time

Effect of different dates of transplanting was studied on area under disease progression curve (AUDPC) and apparent infection rate (r) of Alternaria leaf and flower blight of marigold incited by Alternaria tagetica. The results revealed that maximum AUDPC value was recorded on leaves (540.0 and 598.7) and florets (594.0 and 617.6) in first date of transplanting, respectively in 2013 and 2014. Similarly, maximum apparent infection rate i.e.0.109, 0.108, 0.106 per unit per day occurred on leaves and 0.118, 0.112, 0.119 per unit per day on flowers during November irrespective of date of transplanting. Thus, Alternaria leaf spot and flower blight intensity was highest in early-transplantedas compared to late transplanted crop and can be harnessed for management of disease.