Journal of Phytology 2010, 2(10): 01-05 ISSN: 2075-6240 An Open Access Journal Available Online: www.journal-phytology.com REGULAR ARTICLE PATHOGENICITY AND HOST RANGE OF XANTHOMONAS CAMPESTRIS PV. CAMPESTRIS – INCITANT OF BLACK ROT OF CRUCIFERS Nazir A. Bhat 1* , Nusrath Syeed 2 , K. A. Bhat 1 and S. A. Mir 1 1 Faculty of Agriculture, Sher-e-Kasmir University of Agricultural Sciences & Technology of Kashmir, Wadura, Sopore – 193 201, J&K, India 2 Government College for Women, Maulana Azad Road, Srinagar, J&K, India SUMMARY Black rot caused by Xanthomonas campestris pv. campestris (Pammel) Dowson is a serious disease of cabbage in Jammu and Kashmir. Amongst different inoculation methods tested, ‘Vein inoculation’ method gave quicker symptom expression and highest lesion progression followed by ‘Hydathode inoculation’ and ‘Clip inoculation’ methods, respectively. Spray inoculation for stomatal penetration of the pathogen failed to express any symptoms. Host range studies under conditions of artificial inoculation revealed that the bacterium infected almost all the crucifer crops cultivated in Kashmir, besides some cruciferous weeds but failed to infect any of the non-cruciferous plant species tested. Key words: Black rot, cabbage, host range, pathogenicity, Xanthomonas campestris pv. campestris Nazir A. Bhat et al. Pathogenicity and Host Range of Xanthomonas campestris pv. campestris – Incitant of Black Rot of Crucifers. J Phytol 2/10 (2010) 01-05. *Corresponding Author, Email: nazirpathology@gmail.com 1. Introduction It is often very difficult to reproduce a disease artificially while attempting to prove pathogenicity of its suspected pathogen. Besides providing an environment favourable for the disease development after inoculation of the pathogen, it is essential to adopt an inoculation technique, which is easy to perform and gives good results. Various methods and techniques, based on mode of penetration of pathogens are therefore, developed from time to time to test their pathogenicity. Similarly, knowledge of the host spectrum of a pathogen is of immense value as it helps to earmark various cultivated plants endangered by its infection. These studies also help to understand the mode of survival of a pathogen, particularly during the off-season, when its main host is absent. Black rot is a major disease of cabbage in Kashmir valley where it has been reported to prevail with an incidence and intensity of 26.7–63.3 and 5.8-32.7%, respectively (Bhat and Masoodi, 1999). Although some work on its management in Kashmir has already been conducted (Bhat and Masoodi, 2000 ;Bhat, et al., 2000) but no work has so far been done to study the danger posed by the disease to other vegetable crops cultivated in the valley. Present studies were therefore taken up to compare different techniques for inoculation of Xanthomonas campestris pv. campestris into cabbage for inciting black rot disease and using the most efficient technique for inoculation of other plant species to study the host range of the pathogen. 2. Materials and Methods Four techniques used for inoculating 48 h old culture of X. campestris pv. campestris into 40 days old cabbage (Brassica oleracia var. capitata L.) cv. Golden Acre seedlings, raised in 25 cm earthen pots containing sterile soil, were compared for their efficiency and quick symptom expression. The techniques used were: Hydathode inoculation Potted seedlings were watered in the evening and covered under mist chambers, which were lifted in the morning and a