In vitro efficacy of fungicides against Alternaria alternata (Fr.) Keissler, causing Leaf Blight disease of Chrysanthemum

Abstract

Chrysanthemum {Dendranthema indicum (= Chrysanthemum indicum L.)}, crop is being affected by several fungal, bacterial, viral and nematode induced diseases. However, leaf blight, caused by Alternaria alternata (Fr.) Keissler has been common occurrence, causing quantitative as well as qualitative losses in chrysanthemum. Therefore, present in vitro study was planned in CRD with two separate experiments (Contact and systemic and combi-fungicides) in vitro, in 13 treatments replicated thrice, to assess the efficacy of fungicides against Alternaria alternata, at the Department of Plant Pathology, College of Agriculture, Latur (MS), during Rabi, 2019-20. Results revealed that, all of the six systemic (each @ 500, 1000 and 1500 ppm), five contact and two combi-products fungicides (each @ 1000, 2000 and 2500 ppm) evaluated in vitro were found fungistatic and exhibited significant mycelial growth inhibition of A. alternata, causing Alternaria leaf blight of chrysanthemum. However, the systemic fungicides viz., Propiconazole 25% EC and Hexaconazole 5% EC (100%), followed by Difenconazole 25% EC (87.81%), Penconazole 10% EC (86.13%) were found most effective against the test pathogen. Whereas, among contact / combi – fungicides the most effective fungicide found were Carbendazim 12% WP + Mancozeb 63% WP with highest growth inhibition (81.96%), followed by Mancozeb 75% WP (78.05%), Copperoxy chloride 50% WP (69.36%), respectively.