OCCURRENCE AND PATHOGENICITY OF COMMON SCAB AND SOFT ROT POTATO IN AZAD JAMMU AND KASHMIR (PAKISTAN)

Abstract

Potato (Solanum tuberosum L.) is an important cash and vegetable crop in Pakistan. Azad Jammu Kashmir (AJK) Pakistan being important area in potato cultivation is vulnerable to many pathological problems. Diseases like common scab and soft rot caused colossal losses in potato production. The objective of this study was the field survey of major potato growing areas in AJK and to isolate, identify and characterize bacteria. It was observed that the bacterial diseases were present in the area. The disease incidence indicated that common scab ranges between 20–70%, was severe at Muzzafarabad (70%) followed by disease at Kutan in Neelum valley and Bagh i.e., 20%, respectively. The disease incidence of soft rot range between 20-80%, disease was very severe at Bagh (80 %), moderate at most of the places and lowest at Muzzafarabad (20%). The diseased potato samples collected were subjected to various physiological and biochemical tests for identification and characterization of the pathogen. All isolates of both the bacteria were pathogenic and have shown a hypersensitive response. The results showed that both the Streptomyces scabies and Ervinia carotovora subsp. carotovora were present and established as the causal organism of common scab and soft rot of potato, respectively.  The present study guides about the bacterial diseases prevalent in the area, crop losses occurring and facilitates in development of disease management strategy.