Evaluation of fungicides and bioagent against diplocarpon rosae causing black leaf spot in rose

Abstract

Rose leaves showing typical symptoms of black spot were collected from Horticulture Field, College of Agriculture, Nagpur and used for isolation of pathogen on PDA media. The culture of the pathogen was examined for morphological and cultural characteristics. On the basis of hyphae, shape of spore produced, colour and type of colony, the fungus was identified as Diplocarpon rosae and it proved the Koch’s postulates. The fungicides viz., Azoxystrobin (Amistra), Mancozeb+Carbendazim (Bendaco), Thiophenate methyl (Topsin-M), Mycobutanil (Systhane), Tebuconazole (Folicure), Chlorothalonil (Daconil) and control were evaluated against Diplocarpon rosae. Results revealed that, after third spray, minimum per cent disease intensity was recorded by chlorothalonil 0.2 per cent (11.23 PDI) and topsin M 0.05 per cent (13.50 PDI) and both these treatments were at par with each other. Next promising treatment was myclobutanil (0.1%) followed by mancozeb+carbendazim (0.2%), azoxystrobin (0.1%), T. viride (0.2%) and tebuconazole (0.1%), respectively.