1480 Environment & Ecology 31 (3A) : 1480—1485, July—September 2013 Website: environmentandecology.com ISSN 0970-0420 Molecular and Morphological Characterization of Three Oidium spp. on Ocimum basilicum, Brassica pekinensis and Crotalaria sp. from India P. Baiswar, S. Takamatsu, S. V. Ngachan, Satish Chandra, M. Harada Received 29 April 2013; Accepted 20 May 2013; Published online 28 May 2013 Abstract Powdery mildew was observed on Ocimum basilicum, Crotalaria sp. and Brassica pekinensis. Light and scanning electron microscopy revealed that all the pathogens belonged to Oidium subgenus Pseudoidium (Erysiphe sp.). Molecular phylogenetic analyses based on the 28S rDNA, including the do- mains D1 and D2, and ITS region, including the 5.8S rDNA, also supported the identification based on morphological characteristics. Keywords Phylogenetic, Erysiphe. Introduction In Northeast India many crops are infected by pow- dery mildew disease. Correct identity of the patho- P. Baiswar*, S. V. Ngachan, S. Chandra Division of Plant Pathology, ICAR Research Complex for NEH Region, Umiam 793103, Meghalaya, India S. Takamatsu, M. Harada Graduate School of Bioresources, Mie University, Kurima-machiya 1577, Tsu, Mie Pref. 514-8507, Japan e-mail : pbaiswar@yahoo.com *Correspondence gen is of utmost importance for management as well as quarantine issues. In this study, we have attempted to identify powdery mildews on Ocimum basilicum, Crotalaria sp. and Brassica pekinensis based on criteria suggested by various researchers, i.e. mor- phology of anamorph, germination pattern, scanning electron microscopy and molecular analyses based on ITS and 28S rDNA sequences (1—7). (Authors would like to thank Head, SAIF, Dr Sudeep Dey, Scientific Officer, N. K. Rynjah and Dr R. Chakraborty for scanning electron microscopy (SEM JEOL JSM 6360) at Northeastern Hill University, Shillong, Meghalaya, India. We would also like to thank Dr. D.K. Hore for identification of host plants). Materials and Methods Light and scanning electron microscopy Three percent KOH was used as mounting medium. Latest literature was consulted for identification (2, 3, 8). Voucher specimens have been deposited in MACS Agharkar Research Institute, Pune, India and her- barium collection of ICAR Research Complex for NEH Region, Barapani, Meghalaya, India (Crotalaria sp. AMH No. 9272 and ICARHNEH-49, B. pekinensis AMH No. 9271 and ICARHNEH-51, O. basilicum ICARHNEH-53). Infected leaf samples were cut into 5 mm size and