Screening of Tuberose Cultivars against Leaf Spot (Alternaria polyanthi) and its Management

Background: Tuberose flower has been found to be affected by various fungal and viral diseases which affect growth cause loss in yield. Among them, leaf spot incited Aternaria polianthi is an important disease tuberose. The incidence of the common both single double-type tuberose varieties due prevalence high rainfall humid conditions. During survey it was that increasing gradually causing economic losses Assam. Methods: field trial carried out during kharif seasons (2015 -18) test efficacy six fungicides against (Var. Local petal) caused Alternaria polyantha. Four sprays with at interval seven days starting from first appearance symptom were done. Per cent (%) parameters recorded one week after last spray. Another experiment for screening resistant genotypes conducted using 11 (2016-17 2017-18). Result: Eleven cultivars (Bidhan Ranjani-1, Bidhan Ranjani-2, Arka Nirantara, GK-TC-4, Prajwal, Phule Rajani, Single, Double, Vaibhav, Suhashini Shringer) screened A.polyanthi under natural condition. None immune or resistant, while three viz., Rajani-1 Nirantara showed moderate reaction per 16.11, 18.17 18.71, respectively. Spraying azoxystrobin, difenoconazole a combo fungicide consisting iprodione (25%) + carbendazim (25%), 0.1% lowest 7.91, 9.83 11.85% compared control (33.62 PDI) reduction 70.59%, 64.61% 76.31%,