Disease Mapping of Citrus Greening Disease in District Layyah, Pakistan

Citrus greening disease is one of the established causes of citrus decline in tropical and subtropical areas of the world, including Pakistan. Citrus greening disease is being recognized based on its characteristic symptoms in the field. Symptomatology and Iodo-starch test are the parameters for rapid disease indexing in the field and laboratory and are also helpful for disease mapping. A study was carried out to record the incidence and severity of citrus greening disease within the area of new citrus plantations of Layyah district, including the tehsils viz., Layyah and Karror. The Layyah tehsil showed an incidence of 18%, while Karror showed an incidence of 5.5%. Among the cultivars, the highest disease incidence was attributed to Kinnow (Citrus nobilis x C. deliciosa) at 33% followed by Mosambi (C. sinensis) at 16% and Feutrall’s early at 5%. The highest disease severity was recorded at Layyah with 22.2%. The lowest was observed at Karror with 13.3%. Among the cultivars, Kinnow showed the highest severity, ranging from 27.22% to 36.6% and the least disease severity was recorded in Feutrall’s early of 8.3% at ± 0.05 level of significance. The present study not only helped establish the relationship between the symptomology and quick indexing of disease through iodo-starch test but also provided information through disease mapping in the new citrus plantation of Layyah district for the first time