Studies on some New and Interesting Foliar Diseases of <I>Sterculia urens</I> and their Control

Abstract

The foliar diseases of Sterculia urens Roxb. Caused by Cercoseptoria sterculiae Mehrotra, Alternaria macrospora Zimm. Var. sterculiae Mehrotra, Phoma jobyana Pirozynski & Morgan Jones, P.macrostoma Mont., Myrothecium rotidum Tode ex Fr., Macrophomina phaseolina (Tassi) Gold., and Cercospore stercu1iae Agarwal & Hasija are recorded. Cereoseptoria sterculiae and A. macrospora var. stercu1iae are described as new species and new variety respectively. The other pathogens except Cercospora sterculiae have not been recorded on this host earlier. An account of the disease situation in the nursery and natural forests is given. Both dithana M-45 and cupramar+unizeb applied as foliar spray (0.2%) at fortnightly intervals effectively controlled the diseases in the nursery. Unizeb alone ranked amongst the treatments as the next best. Cupramar was, however, mildly effective.