Geospatial mapping and distribution analysis of common scab disease in core potato-growing districts of Punjab, Pakistan

Among vegetables, the potato is the only crop that serves as a staple food for millions of people worldwide due to its rich nutritional profile. However, the sustainable production of potatoes is significantly challenged by various pathogens and pests. Among major viral, fungal, and bacterial diseases, common scab has emerged as a primary concern for potato crops. Streptomyces scabies, a phytopathogenic species of the Streptomyces genus, is considered the key pathogen in alkaline soils of Pakistan. There is a lack of reliable information regarding the incidence of common scab and the scab index in potato-growing areas of Punjab. To address this, a survey was conducted across four major districts to assess disease incidence, severity, and establish baseline data. A total of 110 locations were surveyed, of which 73 were found to be scab-infected. In Sahiwal, the scab index ranged from 10% to 52.5%; in Okara, from 10.25% to 55.8%; in Kasur, from 10% to 47.81%; and in Pakpattan, from 11.66% to a maximum of 46.6%. The highest disease severity was observed in Okara, while the lowest was recorded in Kasur. The relatively lower scab index compared to previous studies may be attributed to various management strategies implemented at farms during the crop season. This survey provides policymakers with critical data to develop effective strategies for combating common scab in the future.